Communicable Diseases Watch

Communicable Diseases Watch (CDW) is an online bi-weekly on communicable diseases published by the Centre for Health Protection (CHP). The publication aims at providing healthcare professionals with up-to-date infectious disease news and knowledge relevant to . It is also an indication of CHPʼs commitment to responsive risk communication in addressing the growing com- munity interest on infectious diseases.

Communicable Diseases Watch 2018 Compendium © Government of the Hong Kong Special Administrative Region, the Peopleʼs Republic of Copyright 2019

ISSN 1818-4111

Produced and published by Communicable Disease Division Surveillance and Epidemiology Branch Centre for Health Protection Department of Health Government of the Hong Kong Special Administrative Region 147C Argyle Street, Kowloon, Hong Kong Communicable Diseases Watch

2018 Editorial Board Content

Editor-in-chief Volume 15 Number 1 Weeks 1-2 (December 31 2017 - January 13, 2018) Dr. SK Chuang 2017/18 Winter Influenza Season Underway in Northern Hemisphere 1 Members Review of Pneumococcal Vaccination and Invasive Pneumococcal Disease in Dr. Yonnie Lam Hong Kong 4 Dr. Albert Au Two epidemiologically linked cases of invasive pneumococcal Dr. TY Wong Dr. Philip Wong CA-MRSA cases in December 2017 Dr. Benjamin Fung Scarlet update (December 1, 2017 - December 31, 2017) Dr. Gladys Yeung Simon Wong Volume 15 Number 2 Weeks 3-4 (January 14 - January 27, 2018) KK So Sheree Chong Review of Legionnaires’ Disease (LD) in 2017 7 Dr. Shirley Tsang Update on bacillary dysentery in Hong Kong, 2013 to 2018 9 Doris Choi Two sporadic cases of psittacosis Chloe Poon Production Assistants Volume 15 Number 3 Weeks 5-6 (January 28 - February 10, 2018) Yoyo Chu Personal and environmental hygiene during peak season for influenza 11 This publication is produced by the Review of acute outbreaks associated with sapovirus in Hong Centre for Health Protection of the Kong 13 Department of Health, Hong Kong Interim estimates of 2017/18 seasonal influenza vaccine effectiveness in local Special Administrative Region primary healthcare setting Government Two probable cases of sporadic Creutzfeldt-Jakob disease 147C, Argyle Street, Kowloon Hong Kong SAR CA-MRSA cases in January 2018 update (January 1, 2018 – January 31, 2018) ISSN: 1818-4111 ! Volume 15 Number 4 Weeks 7-8 (February 11 - February 24, 2018) All rights reserved 2017 Year in Review 15 Please send enquiries to A probable case of sporadic Creutzfeldt-Jakob disease [email protected]

Volume 15 Number 5 Weeks 9-10 (February 25 - March 10, 2018) Content Highlights Update on Psittacosis 19 Review of hantavirus infection in Hong Kong 20 ‣ Feature articles A cluster of pertussis in a public hospital ‣ News Two local sporadic cases of

Volume 15 Number 6 Weeks 11-12 (March 11 - March 24, 2018) CDW Website Update on the situation of chikungunya fever 22 http://www.chp.gov.hk/cdw Management of scabies outbreak in institutional settings 24 A sporadic case of psittacosis Workshop on Application of Molecular Diagnostics on Clinical Microbiology on March 20 and 21, 2018 CA-MRSA cases in February 2018 Scarlet fever update (February 1, 2018 – February 28, 2018)

i Volume 15 Number 7 Weeks 13-14 (March 25 - April 7, 2018) The Wholesale Supply Data of to Various Sectors in 2014-2016 26 Review of HIV/AIDS epidemiology in 2017 28 Two domestic clusters of pertussis A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection A sporadic case of psittacosis

Volume 15 Number 8 Weeks 15-16 (April 8 - April 21, 2018) Summary of the 2017/18 winter influenza season in Hong Kong 31 Celebrating the World Immunization Week 2018 (April 24 to 30, 2018) 34 A sporadic case of necrotising fasciitis caused by Vibrio vulnificus CA-MRSA cases in March 2018 Scarlet fever update (March 1, 2018 – March 31, 2018)

Volume 15 Number 9 Weeks 17-18 (April 22 - May 5, 2018) Review of measles in Hong Kong (2013-2017) 36 Hand Hygiene Awareness Day (May 5, 2018): It’s in your hands - prevent in healthcare 38 A local sporadic case of Hantavirus infection Two sporadic cases of necrotising fasciitis caused by Vibrio vulnificus A local sporadic case of listeriosis A sporadic confirmed case of

Volume 15 Number 10 Weeks 19-20 (May 6 - May 19, 2018) Scientific Committee’s Recommendations on Seasonal Influenza Vaccination for the 2018/19 Season in Hong Kong 41 Infection control for ambulatory healthcare facilities 42 Two local confirmed cases of human myiasis A local sporadic case of listeriosis CA-MRSA cases in April 2018 Scarlet fever update (April 1, 2018 – April 30, 2018)

Volume 15 Number 11 Weeks 21-22 (May 20 - June 2, 2018) Updated situation of Ebola Virus Disease in Democratic Republic of Congo 45 Updated Guidelines on Malaria Chemoprophylaxis for Travellers from Hong Kong 47 A sporadic confirmed case of brucellosis A local sporadic case of listeriosis A probable sporadic case of Creutzfeldt-Jakob disease A sporadic case of necrotising fasciitis caused by Vibrio vulnificus A sporadic case of psittacosis A domestic cluster of measles

ii Volume 15 Number 12 Weeks 23-24 (June 3 - June 16, 2018) Update on Nipah Virus Infection in India 50 Update on Global and Local Epidemiology of 52 Two sporadic cases of listeriosis A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection A sporadic case of suis infection Infection Disease (ID) Forum "Human Papilloma Virus (HPV) - Next Steps" on June 11, 2018 CA-MRSA cases in May 2018 Scarlet fever update (May 1, 2018 - May 31, 2018)

Volume 15 Number 13 Weeks 25-26 (June 17 - June 30, 2018) Review on non-typhoidal Salmonella food poisoning in Hong Kong, 2013-2018 56 Exercise "Sunstone" tests government response to novel disease 57 A sporadic case of Listeriosis A sporadic case of Streptococcus suis infection A sporadic case of necrotising fasciitis caused by Vibrio vulnificus

Volume 15 Number 14 Weeks 27-28 (July 1 - July 14, 2018) Review of Human Metapneumovirus Infection in Hong Kong 59 Update on Diphtheria in Hong Kong 60 An imported confirmed case of brucellosis A sporadic case of psittacosis A local sporadic case of listeriosis A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection CA-MRSA cases in June 2018 Scarlet fever update (June 1, 2018 – June 30, 2018)

Volume 15 Number 15 Weeks 29-30 (July 15 - July 28, 2018) Review on Dengue Fever in Hong Kong, 2008-2018 63 Review of acute infectious conjunctivitis (ACJ) in Hong Kong, 2014-2018 (as of July 31, 2018) 64 A domestic cluster of pertussis A sporadic case of listeriosis A sporadic case of psittacosis

Volume 15 Number 16 Weeks 31-32 (July 29 - August 11, 2018) Consensus Recommendations on School Closure due to Seasonal Influenza 67 The 18th Tripartite Meeting on Prevention and Control of Infectious Dis- eases and Joint Emergency Response Exercise 69 An imported case of A sporadic case of necrotising fasciitis caused by Vibrio vulnificus A probable case of sporadic Creutzfeldt-Jakob disease IMPACT Mobile APP: Interactive Media Awards 2018 CA-MRSA cases in July 2018 Scarlet fever update (July 1, 2018 – July 31, 2018)

iii Volume 15 Number 17 Weeks 33-34 (August 12 - August 25, 2018) Latest situation of dengue fever in Hong Kong 72 Stay Vigilant Against Communicable Diseases in the New School Year 74 A sporadic case of psittacosis A domestic cluster of pertussis A sporadic case of necrotising fasciitis caused by Vibrio vulnificus A possible sporadic case of Creutzfeldt-Jakob disease A sporadic case of listeriosis A sporadic confirmed case of acute

Volume 15 Number 18 Weeks 35-36 (August 26 - September 8, 2018) Update on the dengue fever outbreak in Hong Kong in 2018 77 among Educational Institutions in Hong Kong in 2017 78 A local case of Streptococcus suis infection Four sporadic cases of necrotising fasciitis caused by Vibrio vulnificus Ad Hoc Infectious Disease Forum: An Update on Dengue Fever A sporadic case of psittacosis CA-MRSA cases in August 2018 Scarlet fever update (August 1, 2018 – August 31, 2018)

Volume 15 Number 19 Weeks 37-38 (September 9 - September 22, 2018) 2018/19 New Initiatives to Promote Seasonal Influenza Vaccination Among School Children 82 Review of grayanotoxin poisoning in Hong Kong, 2012-2018 83 A sporadic case of listeriosis A probable case of sporadic Creutzfeldt-Jakob disease A sporadic local case of Streptococcus suis infection Three domestic clusters of pertussis Two local cases of human myiasis

Volume 15 Number 20 Weeks 39-40 (September 23 - October 6, 2018) Review of hepatitis E infection in Hong Kong 85 Review of Leptospirosis in Hong Kong, 2008-2018 87 A sporadic case of listeriosis A possible sporadic case of Creutzfeldt-Jakob disease Two sporadic cases of necrotising fasciitis due to Vibrio vulnificus infection

Volume 15 Number 21 Weeks 41-42 (October 7 - October 20, 2018) Update of hand, foot and mouth disease (HFMD) activities in Hong Kong 89 Updated situation of Ebola Virus Disease in Democratic Republic of Congo 90 Field Epidemiology Training Programme (FETP) training course 2018 A sporadic case of psittacosis Two local cases of listeriosis A local sporadic case of leptospirosis A domestic cluster of pertussis CA-MRSA cases in September 2018 Scarlet fever update (September 1, 2018 – September 30, 2018)

iv Volume 15 Number 22 Weeks 43-44 (October 21 - November 3, 2018) Update on the global situation of monkeypox infection in humans 94 Update on Norovirus-associated Acute Gastroenteritis Outbreaks in Hong Kong 97 A local case of Streptococcus suis infection A sporadic case of psittacosis Patient Engagement in Hand Hygiene Promotion: The Keys of Success on October 25 and 26, 2018

Volume 15 Number 23 Weeks 45-46 (November 4 - November 17, 2018) Human infection of rat hepatitis E virus (HEV) 100 Regional Symposium on Antimicrobial Resistance 101 A local sporadic case of listeriosis A sporadic case of psittacosis A sporadic case of Streptococcus suis infection CA-MRSA cases in October 2018 Scarlet fever update (October 1, 2018 – October 31, 2018)

Volume 15 Number 24 Weeks 47-48 (November 18 - December 1, 2018) New series of Guidance Notes on Stewardship in Primary Care 104 HPV Vaccination for Cervical Cancer Prevention 105 A sporadic case of Listeriosis infection A sporadic case of psittacosis

Volume 15 Number 25 Weeks 49-50 (December 2 - December 15, 2018) Second dose of measles-containing vaccine for children in Hong Kong to be advanced 108 A sporadic case of Listeriosis A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection A sporadic case of psittacosis A domestic cluster of pertussis CA-MRSA cases in November 2018 Scarlet fever update (November 1, 2018 – November 30, 2018)

Volume 15 Number 26 Weeks 51-52 (December 16 - December 29, 2018) Review of cryptosporidiosis in Hong Kong 111 Update on the situation of listeriosis in Hong Kong 113 A possible case of sporadic Creutzfeldt-Jakob disease A sporadic case of Streptococcus suis infection A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection A domestic cluster of pertussis

v Author Index

Au, Queenie KM Hand Hygiene Awareness Day (May 5, 2018): It’s in your hands - prevent sepsis in healthcare May 2018 Vol 15 No 9 p. 38

Chak, Michelle MY Review of HIV/AIDS epidemiology in 2017 April 2018 Vol 15 No 7 p. 28

Chan, CK Tuberculosis among Educational Institutions in Hong Kong in 2017 September 2018 Vol 15 No 18 p. 78

Chan, Desmond Review of Pneumococcal Vaccination and Invasive Pneumococcal Disease in Hong Kong January 2018 Vol 15 No 1 p. 4

Chan, Hong-lam Update on diphtheria in Hong Kong July 2018 Vol 15 No 14 p. 60

Chan, Kenny CW Review of HIV/AIDS epidemiology in 2017 April 2018 Vol 15 No 7 p. 28

Cheung, Betty WY Hand Hygiene Awareness Day (May 5, 2018): It’s in your hands - prevent sepsis in healthcare May 2018 Vol 15 No 9 p. 38

Choi, Doris Update on bacillary dysentery in Hong Kong, 2013 to 2018 January 2018 Vol 15 No 2 p. 9 Review of cryptosporidiosis in Hong Kong December 2018 Vol 15 No 26 p. 111

Chong, Sheree Update on Nipah Virus Infection in India June 2018 Vol 15 No 12 p. 50 Update on the global situation of monkeypox infection in humans November 2018 Vol 15 No 22 p. 94

Chow, Vera 2017/18 Winter Influenza Season Underway in Northern Hemisphere January 2018 Vol 15 No 1 p. 1 Summary of the 2017/18 winter influenza season in Hong Kong April 2018 Vol 15 No 8 p. 31

Communicable Disease The 18th Tripartite Meeting on Prevention and Control of Infectious Diseases Surveillance and Intelligence and Joint Emergency Response Exercise Office August 2018 Vol 15 No 16 p. 69

vi Emergency Response and Exercise "Sunstone" tests government response to novel disease Information Branch June 2018 Vol 15 No 13 p. 57 The 18th Tripartite Meeting on Prevention and Control of Infectious Diseases and Joint Emergency Response Exercise August 2018 Vol 15 No 16 p. 69

Fong, Ashley Update on Psittacosis March 2018 Vol 15 No 5 p. 19 Review of Human Metapneumovirus Infection in Hong Kong July 2018 Vol 15 No 14 p. 59

Ho, Billy CH Review of HIV/AIDS epidemiology in 2017 April 2018 Vol 15 No 7 p. 28

Ho, Fanny WS Celebrating the World Immunization Week 2018 (April 24 to 30, 2018) April 2018 Vol 15 No 8 p. 34 Review of measles in Hong Kong (2013-2017) May 2018 Vol 15 No 9 p. 36 Second dose of measles-containing vaccine for children in Hong Kong to be advanced December 2018 Vol 15 No 25 p. 108

Ho, King-man HPV Vaccination for Cervical Cancer Prevention December 2018 Vol 15 No 24 p. 105

Kong, Wai-chi Review of acute gastroenteritis outbreaks associated with sapovirus in Hong Kong February 2018 Vol 15 No 3 p. 13 Update of hand, foot and mouth disease (HFMD) activities in Hong Kong October 2018 Vol 15 No 21 p. 89 Update on Norovirus-associated Acute Gastroenteritis Outbreaks in Hong Kong November 2018 Vol 15 No 22 p. 97

Lam, Albert Review of grayanotoxin poisoning in Hong Kong, 2012-2018 September 2018 Vol 15 No 19 p. 83

Lam, Edman TK Infection control for ambulatory healthcare facilities May 2018 Vol 15 No 10 p. 42

Lam, Eric Review of hantavirus infection in Hong Kong March 2018 Vol 15 No 5 p. 20 Updated situation of Ebola Virus Disease in Democratic Republic of Congo June 2018 Vol 15 No 11 p. 45 Review of Leptospirosis in Hong Kong, 2008-2018 October 2018 Vol 15 No 20 p. 87 Updated situation of Ebola Virus Disease in Democratic Republic of Congo October 2018 Vol 15 No 21 p. 90

vii Lam, Karen Updated Guidelines on Malaria Chemoprophylaxis for Travellers from Hong Kong June 2018 Vol 15 No 11 p. 47

Lau, Ka-wing The Wholesale Supply Data of Antibiotics to Various Sectors in 2014-2016 April 2018 Vol 15 No 7 p. 26

Law, WS Tuberculosis among Educational Institutions in Hong Kong in 2017 September 2018 Vol 15 No 18 p. 78

Leung, Hyeon Update on the situation of listeriosis in Hong Kong December 2018 Vol 15 No 26 p. 113

Leung, YH Update on diphtheria in Hong Kong July 2018 Vol 15 No 14 p. 60 Consensus Recommendations on School Closure due to Seasonal Influenza August 2018 Vol 15 No 16 p. 67 Human infection of rat hepatitis E virus (HEV) November 2018 Vol 15 No 23 p. 100 Review of cryptosporidiosis in Hong Kong December 2018 Vol 15 No 26 p. 111

Lui, Leo New series of Guidance Notes on Antibiotic Stewardship in Primary Care December 2018 Vol 15 No 24 p. 104

Man, Emily 2018/19 New Initiatives to Promote Seasonal Influenza Vaccination Among School Children September 2018 Vol 15 No 19 p. 82

Ng, Anthony NM Personal and environmental hygiene during peak season for influenza February 2018 Vol 15 No 3 p. 11 Infection control for ambulatory healthcare facilities May 2018 Vol 15 No 10 p. 42

Ng, Ken The Wholesale Supply Data of Antibiotics to Various Sectors in 2014-2016 April 2018 Vol 15 No 7 p. 26 Regional Symposium on Antimicrobial Resistance November 2018 Vol 15 No 23 p. 101

Ngai, Jonathan Regional Symposium on Antimicrobial Resistance November 2018 Vol 15 No 23 p. 101

Poon, Chloe Management of scabies outbreak in institutional settings March 2018 Vol 15 No 6 p. 24

viii Poon, Cindy Scientific Committee’s Recommendations on Seasonal Influenza Vaccination for the 2018/19 Season in Hong Kong May 2018 Vol 15 No 10 p. 41 Update on Global and Local Epidemiology of Meningococcal Disease June 2018 Vol 15 No 12 p. 52

SS/CDD/SEB/CHP 2017 Year in Review February 2018 Vol 15 No 4 p. 15 Stay Vigilant Against Communicable Diseases in the New School Year August 2018 Vol 15 No 17 p. 74

Tsang, Shirley Review of acute infectious conjunctivitis (ACJ) in Hong Kong, 2014-2018 (as of July 31, 2018) July 2018 Vol 15 No 15 p. 64

Wong, Ambrose Management of scabies outbreak in institutional settings March 2018 Vol 15 No 6 p. 24 Review of grayanotoxin poisoning in Hong Kong, 2012-2018 September 2018 Vol 15 No 19 p. 83

Wong, Francis Review of Legionnaires’ Disease (LD) in 2017 January 2018 Vol 15 No 2 p. 7

Wong, Philip Updated situation of Ebola Virus Disease in Democratic Republic of Congo June 2018 Vol 15 No 11 p. 45

Wong, TY Personal and environmental hygiene during peak season for influenza February 2018 Vol 15 No 3 p. 11 Hand Hygiene Awareness Day (May 5, 2018): It’s in your hands - prevent sepsis in healthcare May 2018 Vol 15 No 9 p. 38 Infection control for ambulatory healthcare facilities May 2018 Vol 15 No 10 p. 42

Wu, Zenith Update on the situation of chikungunya fever March 2018 Vol 15 No 6 p. 22 Review on non-typhoidal Salmonella food poisoning in Hong Kong, 2013-2018 June 2018 Vol 15 No 13 p. 56 Review on Dengue Fever in Hong Kong, 2008-2018 July 2018 Vol 15 No 15 p. 63

Yim, Jess Latest situation of dengue fever in Hong Kong August 2018 Vol 15 No 17 p. 72 Update on the dengue fever outbreak in Hong Kong in 2018 September 2018 Vol 15 No 18 p. 77 Review of hepatitis E infection in Hong Kong October 2018 Vol 15 No 20 p. 85

ix Dec 31 2017 - Jan 13 2018 WEEKS 1 - 2 VOL 15 ISSUE NO 1

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrY onnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / Simon Wong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C, Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected]

FEATURE IN FOCUS 2017/18 Winter Influenza Season Underway in Northern Hemisphere Reported by Ms Vera CHOW, Scientific Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP.

Overview The 2017/18 winter influenza season has already started in most areas in the northern hemisphere and the influenza activity continued to increase or reached a high level. Locally, after the 2017 summer influenza season, the activity of seasonal influenza in Hong Kong had remained at a low level from September to mid-December 2017. It started to increase steadily in late December and exceeded the baseline level in early January, indicating the arrival of the 2017/18 winter influenza season in Hong Kong. The overall seasonal influenza activity has shown a continual increase in the past two weeks with notable increases in laboratory detection of influenza viruses among respiratory specimens, institutional influenza-like illness (ILI) outbreaks and influenza-associated hospitalisation rate in public hospitals. It is anticipated that the local influenza activity may further increase in the coming weeks and remain at an elevated level for some time.

Local seasonal influenza activity Laboratory surveillance The weekly percentage tested positive for seasonal influenza viruses among respiratory specimens received by the Public Health Laboratory Services Branch (PHLSB) of the Centre for Health Protection (CHP) of the Department of Health has increased steadily from 3.93% in the week ending December 16 to 15.13% in the week ending January 6, which exceeded the baseline threshold (Figure 1). It has then increased to 16.73% in the week ending January 13. In typical winter seasons in the past few years, the positive percentage would reach a peak level around 25% to 40%.

Unlike the past three influenza seasons (2016 summer season, 2016/17 winter season and 2017 summer season) predominated by influenza A(H3N2) viruses, influenza B became the most commonly detected virus type in this season (Figure 2). Among the influenza viruses detected in the past four weeks (December 17, 2017-January 13, 2018), the majority were influenza B (76.5%), followed by influenza A (H1) (9.7%), influenza A(H3) (8.4%) and influenza C (5.5%). Among the positive influenza B Figure 1 - Percentage of respiratory specimens tested positive for influenza viruses, 2014-2018. detections from December 17 to (Note: The baseline threshold is 1.96 standard deviation above the average weekly positive percentage during non-season January 6, 88.1% belonged to the periods from 2014-2017.) Yamagata lineage which is included only in the quadrivalent seasonal influenza vaccine (SIV) recommended for the 2017/18 northern hemisphere season but not the trivalent SIV including the Victoria lineage. The last season predominated by influenza B viruses in Hong Kong was the 2015/16 winter season when 43.5% of the positive detections was influenza B. Antigenic characterisation by PHLSB showed that the circulating influenza viruses so far remained Figure 2 - Percentage of respiratory specimens tested positive for influenza virus subtypes, 2014-2018. similar to the components in the COMMUNICABLE DISEASES WATCH 1 Dec 31 2017 - Jan 13 2018 WEEKS 1 - 2 VOL 15 ISSUE NO 1 SIV recommended for the 2017/18 northern hemisphere season and there were no significant antigenic changes. Overseas health authorities also reported that the circulating viruses including influenza A and influenza B viruses remained similar to the vaccine components. Influenza-like illness (ILI) outbreaks in schools and institutions The weekly number of institutional ILI outbreaks reported to CHP increased sharply in the past two weeks. Twenty-six outbreaks in schools and institutions were reported in the week ending January 13, as compared to five outbreaks in the previous week (Figure 3). In the first four days of this week, the number of ILI outbreaks further increased to 49. From January 7 to 17, the reported ILI outbreaks Figure 3 - Weekly number of institutional ILI outbreaks reported to CHP, 2014-2018. occurred in primary schools (50.7%), kindergartens/child care centres (37.3%), residential care homes for the elderly (6.7%), residential care home for people with disabilities (2.7%) and others (2.6%). Influenza-associated hospital admissions in public hospitals The admission rate with principal diagnosis of influenza in public hospitals has increased steadily since mid-December to 0.27 Figure 4 - Weekly admission rates with principal diagnosis of influenza in public hospitals, 2014-2018. admitted cases (per 10 000 (Note: The baseline threshold is 1.96 standard deviation above the average weekly admission rate during non-season periods population) in the last week of from 2014-2017.) December, which was above the baseline threshold (Figure 4). It further increased to 0.45 and 0.52 in the following two weeks. Similar to previous seasons, the rate was highest among young children and elderly (Figure 5). Among children aged below five years, the rate has increased to 3.83 in the week ending January 13. The rate among children aged between five and nine years and elderly aged 65 years or above increased to 2.31 and 0.99 respectively in the same week. Figure 5 - Weekly admission rates with principal diagnosis of influenza in public hospitals by age groups, 2014-2018. Severe influenza cases Since 2018, CHP has collaborated with the Hospital Authority and private hospitals to monitor intensive care unit (ICU) admissions and deaths with laboratory confirmation of influenza among adult patients regularly as a routine surveillance throughout the year. For surveillance purpose, the cases refer to laboratory-confirmed influenza patients who required ICU admission or died within the same admission of influenza infection. Their causes of ICU admission or death may be due to other acute medical conditions (e.g. stroke, acute myocardial infarction, etc.) or underlying diseases (exacerbation of chronic obstructive airway disease, renal failure, malignancy, etc.).

Since the start of the winter influenza season in the week of January 7, a total of 41 adult cases of ICU admissions or deaths with laboratory confirmation of influenza Figure 6 - Weekly number of severe influenza cases by age groups, 2014-2018 (the percentage positive for were recorded (including 23 deaths) influenzas viruses is also shown). (as of January 17) (Figure 6). Among (Note: The surveillance system for severe influenza cases among adult patients aged 18 years or above was only activated them, 34 patients had infection with intermittently during influenza seasons before 2018.)

COMMUNICABLE DISEASES WATCH 2 Dec 31 2017 - Jan 13 2018 WEEKS 1 - 2 VOL 15 ISSUE NO 1 influenza B, five patients with influenza A(H1N1)pdm09, one patient with influenza A(H3N2) and one patient with influenza A pending subtype. 65.9% were aged 65 years or above. Majority of them (94.3%) had underlying medical diseases. Only seven out of the 41 adult cases (17.1%) were known to have received the 2017/18 SIV.

Separately, three paediatric cases of influenza-associated severe /death among patients aged below 18 years were reported to CHP in 2018. All of them had influenza B infection. The first case affected a three-year-old girl with good past health. She was complicated with encephalopathy, and had passed away. The second case affected a three-year-old boy with history of congenital brain malformation and epilepsy. He was complicated with pneumonia and septic shock. Both children did not receive the 2017/18 SIV. The third case affected a 15-year-old girl with history of right middle fossa arachnoid cyst. She was complicated with encephalopathy. She had received SIV for this season.

Seasonal influenza activity in Northern Hemisphere According to the latest update by the World Health Organization, influenza activity continued to increase in the temperate zone of the northern hemisphere. Worldwide, influenza A(H3N2) and B viruses accounted for the majority of influenza detections although influenza A(H1N1)pdm09 viruses were predominant in some countries.

North America In the , the proportion of out-patient visits for ILI reached 2.3% in the week ending November 25, which exceeded the national baseline of 2.2%. It increased to 5.8% in the two weeks from December 30 to January 6. In this season, 87.2% of the positive influenza detections by public health laboratories were influenza A, with the majority (89.9%) being influenza A(H3N2). In Canada, the 2017/18 winter season started in early November last year, which was earlier than previous seasons. So far, 71% of positive influenza detections have been influenza A with H3N2 representing 94% of subtyped influenza A detections.

Europe In , influenza activity was increasing in countries in northern, southern and western Europe. The percentage of respiratory specimens collected at sentinel primary healthcare sites tested positive for influenza viruses has increased from 7% in the week ending November 26 to 44% and 41.8% in weeks ending December 31 and January 7 respectively. Both influenza A and B viruses were co-circulating and mixed patterns were observed across the Region. From October 2 to January 7, 65% of influenza virus detections in sentinel-source specimens were influenza B (mostly Yamagata) while 35% were influenza A (60% H1 and 40% H3).

In the , influenza activity continued to increase in January for all surveillance indicators with notable increases for respiratory outbreaks and influenza confirmed hospitalisations. The overall weekly ILI consultation rates have increased and were above their respective baseline thresholds for England, Wales, Scotland and Northern Ireland. In the first week of January, 28.6% of respiratory specimens were tested positive for influenza viruses. Influenza A and B are co-circulating in this season (47% and 53% in the week ending January 7 respectively). Of note, the weekly ICU influenza admission rate and the weekly influenza hospitalisation rate have greatly exceeded the respective peak levels recorded in the 2016/17 season.

Neighbouring areas In , the winter influenza season arrived earlier this year. In early January, the influenza activity in both Southern and Northern China was still on an increasing trend. The proportion of ILI cases in emergency and outpatient departments reported by sentinel hospitals was higher than that reported in the corresponding period in 2014-2016 in both Southern and Northern China. The most common influenza virus detected currently was influenza B (70.1% in Southern China and 47.5% in Northern China). In Guangdong, the influenza activity has been increasing since December. The ILI consultation rate has exceeded the baseline level of about 4% in mid-December and continued to increase to 6.36% and 5.79% in the first two weeks of January. The laboratory positive percentage of influenza viruses was 41.73% in the week ending January 14 with 96% being influenza B viruses. In , the influenza season has arrived in late December 2017 with increasing influenza activity. The proportions of ILI cases in emergency department were 13.87% and 13.18% in the first two weeks of January, which was above the threshold of 11.4%. The predominating virus was influenza B which constituted about 70% of the influenza detections.

In Japan, the average number of reported ILI cases per sentinel site increased to 1.47 in the week ending November 26, which was above the baseline of 1.00. It then continued to increase to 17.88 and 16.31 in the weeks ending December 31 and January 7 respectively.

Preventive measures It is anticipated that the local seasonal influenza activity will stay at an elevated level for some time. CHP will continue to closely monitor the influenza situation in Hong Kong and overseas countries. All persons aged six months or above except those with known contraindications are recommended to receive SIV for personal protection as soon as possible. During the influenza season, the public, particularly children, the elderly and chronic disease patients, should observe strict personal, hand and environmental hygiene. They should promptly seek medical advice if influenza-like symptoms develop so that appropriate treatment can be initiated as early as possible to prevent potential complications. Parents and carers are reminded to render assistance in prevention, care and control for vulnerable people.

COMMUNICABLE DISEASES WATCH 3 Dec 31 2017 - Jan 13 2018 WEEKS 1 - 2 VOL 15 ISSUE NO 1 Review of Pneumococcal Vaccination and Invasive Pneumococcal Disease in Hong Kong Reported by Mr Desmond CHAN, Scientific Officer, Vaccine Preventable Disease Office, Surveillance and Epidemiology Branch, CHP.

Pneumococcal diseases The bacterium (also known as pneumococcus) is a common causative agent for such as acute otitis media and pneumonia. It also causes various forms of invasive pneumococcal disease (IPD) such as and sepsis. IPD can occur in persons of any age but the mortality is substantially higher among people at extremes of age (children under two years of age and elders aged 65 years or above). Persons who have history of clinical IPD, are immunocompromised, have underlying chronic illnesses, or have cochlear implants are at higher risk of IPD.

Pneumococcal vaccines There are two types of pneumococcal vaccines available on the market, namely the 23-valent pneumococcal polysaccharide vaccine (23vPPV) and pneumococcal conjugate vaccines (PCV) (Figure 1). There are more than 90 serotypes of pneumococci and not all serotypes are covered by the vaccines. 23vPPV consists of pneumococcal capsular polysaccharides for 23 serotypes. PCV consists of pneumococcal capsular polysaccharides conjugated to carrier proteins. There are three types of PCV consisting of antigens against seven, ten and 13 serotypes (PCV7, PCV10 and PCV13 respectively). With the increasing use of PCV10 and PCV13, PCV7 Figure 1 - Serotypes covered by different pneumococcal vaccines. has been gradually phased out from the market.

Pneumococcal vaccination in Hong Kong Following the recommendation of the Scientific Committee on Vaccine Preventable Diseases (SCVPD) under the Centre for Health Protection (CHP) of the Department of Health (DH), PCV7 was incorporated into the Hong Kong Childhood Immunisation Programme (HKCIP) in September 2009. regimen of PCV in the HKCIP includes a three-dose primary series given at the age of two months, four months and six months, and a booster dose given at 12 to 15 months of age. PCV7 used initially was later replaced by PCV10 and PCV13 in October 2010 and December 2011 respectively. According to the 2015 immunisation survey on preschool children conducted by DH, high PCV coverage was achieved for local-born children eligible for the standard PCV programme1.

SCVPD also recommended elders aged 65 years or above to receive 23vPPV in 2009. The Government has provided 23vPPV to elders aged 65 years or above through the Elderly Vaccination Subsidy Scheme (EVSS) and the Government Vaccination Programme (GVP) since 2009. In December 2015, SCVPD updated its recommendation of pneumococcal vaccination for elders and high-risk individuals. The updated recommendation includes either a single dose of PCV13 or a single dose of 23vPPV for elders aged 65 years or above without high risk conditions. High-risk individuals aged two years or above should receive a single dose of PCV13, followed by a single dose of 23vPPV one year later. Eligible elders can receive free or subsidised PCV13 under GVP and EVSS respectively starting in October 2017.

Surveillance and epidemiology of IPD in Hong Kong To monitor the local trend of IPD, serotype replacement and antimicrobial resistance, microbiology laboratories of public and private hospitals in Hong Kong started to send pneumococcal isolates to the Public Health Laboratory Services Branch (PHLSB) of CHP since 2007 via the laboratory surveillance system for IPD. To enhance surveillance, IPD was listed as a notifiable infectious disease under the Prevention and Control of Disease Ordinance (Cap 599) in 2015. Since then, medical practitioners are required to notify DH of any laboratory confirmed cases of IPD (either by detection of DNA by polymerase chain reaction [PCR] or isolation of the bacteria by culture). As such, the surveillance of IPD has extended to include cases diagnosed only by PCR.

From 2007 to 2017, there were 1 734 cases of IPD recorded under the above laboratory surveillance system and statutory notification. The annual IPD incidence ranged from 1.7 to 2.9 per 100 000 population from 2007 to 2017 (Figure 2), which was lower than that recorded in overseas countries that have introduced PCV in their childhood immunisation programmes such as the United States2, Australia3 and New Zealand4 (with a range of eight to 10 per 100 000 population).

IPD incidence was highest among children aged under five years and elderly aged 65 years or above (Figure 3). The incidence among young children aged under two years has decreased gradually from about 10 per 100 000 population in 2007 and 2008 to less than three per 100 000 population in recent years (2015 to 2017) (Figure 3). The reduction is most noticeable for the seven serotypes covered by PCV7/10/13 (PCV7 serotypes) (Figure 4).

On the other hand, the incidence of IPD among children aged two Figure 2 - IPD incidence in Hong Kong, 2007-2017. (Source of data: 2007-2014: PHLSB laboratory surveillance (bacterial culture only); 2015 to four years and those aged five to 17 years apparently increased in onwards: IPD notification to CHP (bacterial culture + PCR)) COMMUNICABLE DISEASES WATCH 4 Dec 31 2017 - Jan 13 2018 WEEKS 1 - 2 VOL 15 ISSUE NO 1 recent years, which may be partly due to an increase in the number of cases detected only by PCR since 2015 (Figure 3). Similar to children aged under two years, IPD incidence caused by PCV7 serotypes has also decreased among children aged two to four years in recent few years. However, for children aged two to four years and those aged five to 17 years, most cases (78%, or 87 of 112) recorded in the recent few years (2015-2017) were caused by serotypes covered by PCV13 but not by PCV7 (PCV13, non-PCV7 serotypes), with the majority (89%, or 77 of 87) being serotype 3 (Figure 4). Incidence caused by these serotypes appeared stable for other age groups.

For adults, IPD incidence increased with age and was the highest among those aged 65 years or above. For elders aged 65 years or above, the overall IPD Figure 3 - Age-specific incidence of IPD in Hong Kong, 2007-2017. (Source of data: 2007-2014: PHLSB incidence remained stable in recent laboratory surveillance (bacterial culture only); 2015 onwards: IPD notification to CHP (bacterial culture + PCR)) years (Figure 3). The incidence caused by PCV7 serotypes had decreased from about three per 100 000 population in 2007 and 2008 to about one per 100 000 population from 2015 to 2017 (Figure 4). This reduction was likely contributed by both the direct effect of 23vPPV in vaccinated elderly and an indirect effect of the PCV vaccination in children.

Serotype 3 pneumococci (one of the PCV13, non-PCV7 serotypes, Figure 4) was the most frequently detected among IPD cases in recent years, accounting for 68% and 40% in children and adults respectively from 2015 to 2017. Although serotype 3 is covered by PCV13 and 23vPPV, the level of immune response against serotype 3 was lower compared to other vaccine serotypes in an immunologic non-inferiority study5 and the vaccine effectiveness against this serotype was reported to be lower Figure 4 - IPD incidence by vaccine serotypes, 2007-2017. (Source of data: 2007-2014: PHLSB laboratory compared to other vaccine serotypes in surveillance (bacterial culture only); 2015 onwards: IPD notification to CHP (bacterial culture + PCR)) overseas vaccine effectiveness studies6,7.

As no existing pneumococcal vaccines can confer protection against all strains of pneumococci, IPD can still occur in vaccinated individuals. In addition to age-appropriate pneumococcal vaccination, there are other measures in preventing . First, personal and environmental hygiene should be observed, such as maintaining good indoor ventilation and wearing masks when having respiratory symptoms. People should seek medical attention early if they have fever and respiratory symptoms. Second, as co-infection with influenza will lead to more severe illness caused by IPD, members of the public except those with known contraindications should receive seasonal influenza vaccine (SIV) as recommended by SCVPD. Dual vaccination of SIV and pneumococcal vaccines may offer further protection particularly among the elderly.

References 1Centre for Health Protection, Department of Health, Hong Kong SAR, Immunisation Coverage for Children Aged Two to Five: Findings of the 2015 Immunisation Survey. Communicable Diseases Watch, 2017. 14(6). 2Centers for Disease Control and Prevention. Surveillance and Reporting. Accessed on September 6, 2017; Available at: https://www.cdc.gov/pneumococcal/surveillance.html. 3Department of Health & Ageing, Australian Government. Invasive pneumococcal disease in Australia, 2011 and 2012. Accessed on January 15, 2017; Available at: http://www.health.gov.au/internet/main/publishing.nsf/content/cda-cdi4002k.htm. 4Ministry of Health, New Zealand. Immunisation Handbook 2017. Accessed on January 15, 2018; Available at: https://www.health.govt.nz/system/files/documents/publications/imm-handbook-15-pneumococcal-disease-may17_1.pdf. 5Kieninger, D.M., et al., Safety, tolerability, and immunologic noninferiority of a 13-valent pneumococcal conjugate vaccine compared to a 7-valent pneumococcal conjugate vaccine given with routine pediatric vaccinations in Germany. Vaccine, 2010. 28(25): p. 4192-203. 6Andrews, N.J., et al., Serotype-specific effectiveness and correlates of protection for the 13-valent pneumococcal conjugate vaccine: a postlicensure indirect cohort study. Lancet Infect Dis, 2014. 14(9): p. 839-46. 7Andrews, N.J., et al., Impact and effectiveness of 23-valent pneumococcal polysaccharide vaccine against invasive pneumococcal disease in the elderly in England and Wales. Vaccine, 2012. 30(48): p. 6802-8. COMMUNICABLE DISEASES WATCH 5 Dec 31 2017 - Jan 13 2018 WEEKS 1 - 2 VOL 15 ISSUE NO 1 NEWS IN BRIEF

Two epidemiologically linked cases of invasive pneumococcal infection

The Centre for Health Protection (CHP) recorded two linked cases of invasive pneumococcal infection in December 2017. The first case was a three-year-old girl with good past health. She developed fever, cough and shortness of breath on December 11. She was admitted to a private hospital on December 17 and was transferred to the paediatric intensive care unit of a public hospital for further management on the same day. Her culture collected on December 17 was tested positive for Streptococcus pneumoniae serotype 3, while her nasopharyngeal swab collected on the same day was tested positive for both enterovirus/ rhinovirus and parainfluenza virus type 1.

The second case was another three-year-old girl with good past health. She studied in the same kindergarten (KG) as the first patient but in a different class. She developed similar symptoms on December 10. She was admitted to a private hospital on December 13 and was transferred to a public hospital for further management on December 15. Her pleural fluid collected on December 16 was tested positive for Streptococcus pneumoniae serotype 3, while her nasopharyngeal aspirate collected on December 15 was tested positive for enterovirus/ rhinovirus. Her sister had upper respiratory tract symptoms before and had recovered.

Both patients remained in stable condition. They have been immunised with Pneumococcal Conjugate Vaccine according to the Hong Kong Childhood Immunisation Programme. Other home contacts remained asymptomatic. There was an upper respiratory tract infection outbreak in the KG attended by the two patients. All affected students remained in stable condition. Officers of the CHP have conducted site visit and provided health advice to the school.

CA-MRSA cases in December 2017

In December 2017, CHP recorded a total of 97 cases of community-associated methicillin resistant (CA- MRSA) infection, affecting 47 males and 50 females with ages ranging from 28 days to 80 years (median: 34 years). Among them, there were 69 Chinese, 10 Filipinos, 2 Caucasian, 2 Indian, 2 Korean, 2 Pakistani, 2 Sri Lankan, 1 Indonesian and 7 of unknown ethnicity. All cases presented with uncomplicated skin and soft tissue infections.

The CA-MRSA isolate of one case was found to be resistant to mupirocin. The patient was a 10-year-old girl who presented with perianal in mid-December 2017. She recovered after treatment with antibiotics and surgical drainage. She previously had an uncomplicated episode of CA-MRSA infection in April 2017. Her isolate at the time was also found to be resistant to mupirocin.

Among the 97 cases, two sporadic cases involved healthcare workers. One was a nurse working in a public hospital while the other was a care worker working in an Integrated Home Care Services Centre. Investigation did not reveal any epidemiologically linked cases. Besides, five household clusters, with each affecting two persons, were identified in December.

Scarlet fever update (December 1, 2017 – December 31, 2017)

Scarlet fever activity in December markedly increased as compared with that in November. CHP recorded 414 cases of scarlet fever in December as compared with 263 cases in November. The cases recorded in December included 247 males and 167 females aged between three months and 49 years (median: six years). There were 15 institutional clusters occurring in eight kindergartens/child care centres and seven primary schools, affecting a total of 33 children. No fatal cases were reported in December. Of note, scarlet fever activity in Hong Kong has increased since late October and currently remains at a high level. Parents have to take extra care of their children in maintaining strict personal, hand and environmental hygiene. Scarlet fever can be effectively treated with antibiotics. People presenting with symptoms of scarlet fever (such as fever, sore throat and skin rash) should consult a doctor promptly for early diagnosis and treatment. Besides, children suffering from scarlet fever should refrain from attending school or child care setting until fever has subsided and they have been treated with antibiotics for at least 24 hours.

COMMUNICABLE DISEASES WATCH 6 Jan 14 - Jan 27 2018 WEEKS 3 - 4 VOL 15 ISSUE NO 2

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrY onnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / Simon Wong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C, Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected]

FEATURE IN FOCUS Review of Legionnaires’ Disease (LD) in 2017 Reported by Dr Francis WONG, Medical and Health Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP.

Legionnaires' Disease (LD) is a type of bacterial pneumonia caused by legionella, most commonly Legionella pneumophila serogroup 1 (Lp1). Legionellae are ubiquitous in aqueous environments including fresh water environment as well as man-made water systems such as potable water supplies systems.

Since 2016, the Centre for Health Protection (CHP) of the Department of Health has adopted a revised risk-based strategy for environmental investigation and sampling for LD cases according to recommendations by CHP's Scientific Committee on Emerging and Zoonotic Diseases after reviewing the local epidemiology as well as drawing reference to prevention and control practices overseas. This article reviews the LD cases reported to CHP in 2017.

Epidemiology of LD cases in 2017 CHP recorded a total of 72 LD cases in 2017 with an incidence rate of 0.97 per 100 000 population (Figure 1), as compared with 75 cases (1.02 per 100 000 population) and 66 cases (0.90 per 100 000 population) in 2016 and 2015 respectively. The local incidence rate in 2017 was within the range of about 0.5 to 2.0 cases of LD or legionellosis per 100 000 population observed in recent years in some overseas or neighbouring countries/areas including Australia, Europe, Japan, Taiwan, the United Kingdom and the United States.

Among the 72 LD cases recorded in 2017, 70 were Chinese and the remaining two cases involved an Australian and a British. Their ages ranged between 39 and 99 years (median: 68 years). The majority (65, 90.3%) of the cases affected persons aged 50 years or above. Males were predominately affected with a male to Figure 1 – Annual number and incidence rate of reported LD cases in female ratio of 5:1. Hong Kong, 2013-2017. The main presenting symptoms included fever (86.1%), cough (75.0%), shortness of breath (61.1%) and malaise (25.0%). All patients developed pneumonia requiring hospitalisation. Twenty-nine patients (40.3%) required intensive care. Nine patients died within the same admission for LD (seven due to LD and the other two due to concomitant diseases).

Regarding the positive test leading to the initial diagnosis of LD, 61 (84.7%) and 10 (13.9%) cases were initially diagnosed by urinary antigen test (UAT) and polymerase chain reaction (PCR) of respiratory specimens respectively, while only one case (1.4%) was initially diagnosed by culture of respiratory specimen.

Fifty-one cases (70.8%) and 10 cases (13.9%) were classified as locally acquired and imported infections respectively, while the place of infection of the remaining 11 cases (15.3%) could not be determined because the patients had stayed both inside and outside Hong Kong during their Figure 2 – Geographic distribution of the residential places of the 51 locally- incubation periods (IP). acquired LD cases during the IP. (Source: Communicable Disease Information System) COMMUNICABLE DISEASES WATCH 7 Jan 14 - Jan 27 2018 WEEKS 3 - 4 VOL 15 ISSUE NO 2 Among the imported cases, there were three epidemiologically linked imported cases involving three patients who had stayed in or visited the same hotel in Macau during the IP and their Lp1 isolates were of the same sequence base type (ST2338).

The residential places of the 51 local cases during the IP were distributed in various districts in Hong Kong (Figure 2). Two patients with onset in late November resided in the same residential care home for the elderly (RCHE). The remaining local cases were sporadic cases.

LD cases with environmental investigations undertaken and environmental samples collected According to CHP’s current investigation strategy, environmental investigations were undertaken and environmental samples were collected for 12 locally acquired cases. Except for a nosocomial case found to be related to tap water in the hospital ward, the sources of infection of the remaining 11 cases could not be confirmed/determined after environmental investigations. The details of the 12 cases are as follows:

Two cases staying in hospital for the whole or majority of the IP One nosocomial case involved a patient with underlying medical conditions who was hospitalised in a public hospital during the whole IP. In the initial investigation, a total of 12 water samples were collected from the hospital. Five water samples (four collected from water taps and one from a shower) were tested positive for Legionella species ranging from 0.1 to 1.4 colony forming units per millilitre (cfu/ml). Chemical disinfection of the relevant water system was performed by the concerned hospital. Post-disinfection water samples were below the action level (i.e. 1 cfu/ml). Sequence-based typing showed that the Lp1 isolates from a water sample collected from the water tap in the toilet of the patient’s room and the patient’s respiratory specimen belonged to the same sequence type (ST1).

Another case involved a patient with underlying medical conditions who was hospitalised in a private hospital during most of the IP (for nine days before onset). In the initial investigation, a total of 11 water samples were collected from the hospital. Seven water samples (three from a shower, two from a water tap and two from a water dispenser) were tested positive for Legionella species ranging from 0.1 to 5.6 cfu/ml. The hospital was advised to carry out disinfection of the water system(s) concerned before resumption of clinical services. No positive respiratory specimens were available from the patient for matching. The source of infection of this case could not be confirmed.

Three cases involving RCHEs Two patients with underlying medical conditions lived in the same RCHE in Aberdeen. Both had onset of symptoms in late November. A total of 12 water samples and six environmental swabs were collected from the washroom used by both patients. Water samples were also collected from a fresh water cooling towers (FWCT) in a nearby building facing the restaurant patronised by both patients during the IP. All water and environmental samples were tested negative for legionella. The source of infection of these two epidemiologically linked cases could not be confirmed.

One patient with underlying medical conditions lived in another RCHE in . In the initial investigation, a total of 12 water samples were collected from the room where the patient had stayed. Four water samples collected from a water dispenser were tested positive for Legionella species ranging from 0.2 to 40.5 cfu/ml. The RCHE was advised to stop using the water dispenser. Sequence based typing of the Lp1 isolates from the patient’s tracheal aspirate and one positive water sample showed that they were of different sequence types. The source of infection of this case could not be confirmed.

One case with undetermined onset date who had prolonged hospitalisation The patient had stayed in a private hospital for management of her underlying medical conditions and was later diagnosed to have LD after being discharged from the hospital. However, due to the complicated disease course and her underlying medical conditions, the onset date and the exposure period could not be determined. A respiratory specimen taken 17 days after her admission was tested positive for Lp1 upon testing. One water sample taken from a cold water dispenser on a floor where the patient had stayed before the collection of first available positive respiratory specimen was tested positive for Lp1 at 0.2 cfu/ml. Sequence based typing of the Lp1 isolates from a respiratory specimen of the patient and the positive water sample of the water dispenser showed that they were of the same sequence type (ST1). The hospital had suspended the use of the concerned water dispenser. The source of infection of this case could not be confirmed.

One community-acquired case involving use of spa The case involved a patient with underlying medical conditions who had visited a spa during the IP. A pair of water samples was taken from the warm water spa pool and were tested negative for legionella species. The source of infection of this case could not be determined.

Cases with onset within six months and common exposure to the same potential sources during IP (two clusters involving five cases) The first cluster involved three patients with common exposure to two sets of FWCTs. Among them, two patients lived in the same housing estate in Kwun Tong but in different blocks and one patient lived in another housing estate. They had onset of illness during the period from June to August. Respiratory specimens collected from one patient in the first estate and another patient in the second estate were tested positive for the same sequence type of Lp1 (ST507) while no respiratory specimen was collected from the remaining patient. Epidemiological investigations revealed that there were two sets of FWCTs, comprising eight FWCTs in total, common to the residences of the three patients. One set of six FWCTs were under the Electrical and Mechanical Services Department’s FWCT Scheme and had monthly water samples collected in May to July tested negative for legionella species. One water sample collected from a FWCT of the second set was tested positive for Legionella pneumophila serogroup 2-14 (Lp2-14) at 200 cfu/ml, which was different from Lp1 detected in the patients. A post-disinfection water sample was below the action level (i.e. less than 10 cfu/ml). COMMUNICABLE DISEASES WATCH 8 Jan 14 - Jan 27 2018 WEEKS 3 - 4 VOL 15 ISSUE NO 2 The second cluster involved another two patients living in the same building in Sai Kung. Both cases had onset in August. Two water samples taken from water tanks in the building were tested negative for legionella species. Another water sample taken from a decorative waterfall with pond located in the vicinity of the building was tested positive for Lp2-14 at 0.1 cfu/ml (below action level of 10 cfu/ml), which was different from Lp1 detected in the two patients. The source of infection of these two clusters could not be determined.

Discussion In summary, the number of LD cases recorded in 2017 was similar to that in 2016. The increasing trend observed in the past decade brought about by the increasing use of sensitive diagnostics tests (UAT and PCR) apparently stabilised. The epidemiological features were similar to the cases reported in previous years. Environmental investigations in 2017 highlighted that water dispensers with water supplied directly from mains water might be contaminated with legionella. This will pose a risk to people with weakened immunity, especially those with chronic illnesses (such as cancer, diabetes mellitus, chronic lung or kidney diseases) and those taking corticosteroids or drugs that suppress body immunity. For prevention of LD, immunocompromised persons must not consume water from water dispensers with direct water supply from mains water. They should use sterile or boiled water for drinking, tooth brushing and mouth rinsing. They should also avoid using humidifiers, or other mist- or aerosol-generating devices. Shower may also generate small aerosols. Further information on LD is available from the designated webpage of CHP (http://www.chp.gov.hk/en/view_content/24307.html).

Update on bacillary dysentery in Hong Kong, 2013 to 2018 Reported by Ms Doris CHOI, Scientific Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Bacillary dysentery, or , is an acute enteric infection caused by bacteria of the genus Shigella. It is transmitted via the faecal-oral route, either directly from person-to-person contact or sexual contact or indirectly through consumption of contaminated food, water or fomites1. The incubation is usually one to three days but could be up to seven days. There are four species of Shigella, namely, Shigella dysenteriae (S. dysenteriae), S. flexneri, S. boydii and S. sonnei. The illness is characterised by sudden onset of fever, diarrhoea with abdominal cramps and or vomiting. The stool may contain blood and mucus. The severity of the illness varies according to the species. S. sonnei infections often result in a short clinical course and the case-fatality rate is almost negligible, except in immunocompromised hosts1. The serotype S. dysenteriae serotype 1 (Sd1) causes epidemic dysentery and is often associated with serious disease and complications such as toxic megacolon, intestinal perforation and haemolytic ureamic syndrome2.

In Hong Kong, bacillary dysentery is a notifiable infectious disease. From 2013 to 2018, as of January 29, the Centre for Health Protection (CHP) of the Department of Health recorded a total of 238 confirmed cases. A decreasing trend of the disease was observed with the annual number of reported cases decreasing from 66 cases in 2013 to 37 cases in 2017 (Figure 1). Fifty-five percent of the patients were females (Figure 2). All age groups were affected, with the age of the patients ranging from two years to 84 years (median: 30 years). Patients aged between 21 and 40 years accounted for over half (52.9%) of the cases (Figure 2). The patients commonly presented with fever (74.8%), followed by abdominal pain (71.4%), watery diarrhoea (70.2%) and diarrhoea (68.5%). Most of the cases (N=179, 75.2%) required hospitalisation and the length of stay in hospitals ranged from one to 34 days (median: three days). No fatal case was recorded.

While bacillary dysentery cases were recorded throughout the year, Figure 1 – Annual number of confirmed bacillary dysentery in more cases were recorded between July and December (Figure 3). One Hong Kong, 2013 to 2018* (N=238). * hundred and forty-two (59.7%) and 88 (37.0%) cases were classified as Provisional figures as of January 29, 2018. locally acquired and imported infections respectively while the places of infection of the remaining eight cases could not be ascertained as the patients had stayed both locally and overseas during (Figure 3). Among the 88 imported cases, the most common countries/ areas of infection were Thailand (15), India (13) and Mainland China (13), followed by Cambodia (8), Pakistan (8), Indonesia (6), the Philippines (6), Vietnam (4), Nepal (3) and others (12). As for clustering, the majority (92.9%) were sporadic cases while eight clusters affecting a total of 17 persons were recorded. The size of the clusters ranged from two to three persons (median: two persons). Seven clusters were related to locally acquired infection and one cluster was acquired the infection from Thailand. Five clusters (62.5%) were foodborne and the suspected incriminated food items included dairy products, , and sandwiches. For the remaining three home clusters, the Figure 2 - Number of confirmed bacillary dysentery reported to source of infection could not be identified as the patients could not CHP by age group and gender, 2013 to 2018* (N=238). recall any relevant exposure history. *Provisional figures as of January 29, 2018.

COMMUNICABLE DISEASES WATCH 9 Jan 14 - Jan 27 2018 WEEKS 3 - 4 VOL 15 ISSUE NO 2 Similar to the pattern of circulating species in developed countries such as England and the United States3,4, S. sonnei was predominant in Hong Kong and caused 67.7% of the cases recorded during this period, followed by S. flexneri (29.4%). Cases caused by S. boydii (1.3%) and S. dysenteriae (1.3%) were uncommon. Based on the available antibiotic sensitivity tests, 46.8% of S. sonnei isolates were resistant to , and 26.6% were resistant to ciprofloxacin. The majority (85.7%) of S. flexneri isolates were resistant to ampicillin but 61.2% were susceptible to ceftriaxone, which was considered as a second line treatment.

Maintenance of good personal hygiene, especially hand hygiene, and adherence to food and water safety are the mainstay of prevention of the Figure 3 - Monthly number of bacillary dysentery cases by disease. People are advised to wash hands properly, especially after going importation status, 2013 to 2018* (N=238). *Provisional figures as of January 29, 2018. to toilet, and before preparing and eating food. Travellers are advised to observe food hygiene and drink water only from safe sources, especially when going to places with poor sanitation.

Protect yourself against bacillary dysentery

1. Maintain good personal, food and environmental hygiene. Adopt the Five Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases. 2. Wash hands properly with liquid soap and water before eating or handling food, and after going to toilet or handling faecal matter. 3. Drink only boiled water from the mains or bottled drinks from reliable sources. 4. Avoid drinks with ice of unknown origin. 5. Purchase fresh food from hygienic and reliable sources. Do not patronise illegal hawkers. 6. Eat only thoroughly cooked food. 7. Wash and peel fruit by yourself and avoid eating raw vegetables. 8. Exclude infected persons and asymptomatic carriers from handling food and from providing care to children, elderly and immunocompromised people. 9. Refrain from work or school, and seek medical advice if suffering from gastrointestinal symptoms such as diarrhoea.

Please visit the website of the Centre for Food Safety (http://www.cfs.gov.hk) for more information on food safety.

References 1David L. Heymann. Control of Communicable Diseases Bowen A, editor: American Public Health Association; 2015. 2Anna Bowen. CDC Yellow Book 2018 - Shigellosis: Centers for Disease Control and Prevention; 2017 (Accessed on January 26, 2018). Available at: https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/shigellosis. 3Centers for Disease Control and Prevention. National Enteric Disease Surveillance: Shigella Annual Report, 2011 : Centers for Disease Control and Prevention; 2013 (updated January 14, 2013). Accessed on January 26, 2018. Available at: https://www.cdc.gov/ncezid/dfwed/pdfs/shigella-annual-report-2011-508c.pdf. 4Shigella cases: 1992 to 2013 [Internet]. Public Health England. Accessed on January 25, 2018. Available at: https://www.gov.uk/government/publications/shigella-cases-1992-to-2013.

NEWS IN BRIEF

Two sporadic cases of psittacosis

On January 19 and 25, 2018, the Centre for Health Protection recorded two cases of psittacosis. The first case affected a 49-year-old woman with unremarkable past health. She presented with fever, , , cough and shortness of breath on January 7 and was admitted to a public hospital on January 14. Her sputum and nasopharyngeal swab were tested positive for Chlamydophila psittaci DNA. She was treated with antibiotics and was discharged on January 17. She had travelled with her family members to Huizhou during the incubation period.

The second case affected a 77-year-old man with underlying illnesses. He presented with fever, headache, myalgia, anorexia, cough with blood-stained sputum and shortness of breath on January 10 and was admitted to another public hospital on January 15. His sputum collected on January 20 was tested positive for Chlamydophila psittaci DNA. He was treated with antibiotics and was discharged on January 23. He had travelled with his wife to Macau during the incubation period.

Investigation did not identify epidemiological linkage between the two cases. Both cases reported no history of contact with birds or their excreta. Their home contacts and travel collaterals were asymptomatic.

COMMUNICABLE DISEASES WATCH 10 Jan 28 - Feb 10 2018 WEEKS 5 - 6 VOL 15 ISSUE NO 3

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrY onnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / Simon Wong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C, Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected]

FEATURE IN FOCUS Personal and environmental hygiene during peak season for influenza Reported by Mr Anthony NG, Senior Nursing Officer and Dr TY WONG, Head, Infection Control Branch, CHP.

Seasonal influenza is an acute illness of the respiratory tract caused by influenza viruses. It is usually more common in periods from January to March and from July to August in Hong Kong. Three types of seasonal influenza viruses are recognised to cause human infection, namely A, B and C. Influenza A viruses can further be subtyped on the basis of two surface antigens: haemagglutinin (H) and neuraminidase (N).

Influenza viruses mainly spread through droplets when infected people cough, sneeze or talk. The infection may also spread by direct contact with the secretions of infected persons via mucosal surfaces of eyes, nose and mouth. It can cause serious illnesses in high-risk individuals and even healthy persons. Given that seasonal influenza vaccines are safe and effective, all persons aged six months or above, except those with known contraindications, are recommended to receive influenza vaccine for personal protection (Details of Vaccination Schemes: https://www.chp.gov.hk/en/features/17980.html).

Meanwhile, adopting personal and environmental hygiene practices are also equally important to protect individuals and the public against seasonal influenza and other respiratory illnesses during peak season.

Personal hygiene Since influenza can be transmitted through droplet or contaminated items, performing hand hygiene properly, maintaining respiratory hygiene and adopting healthy lifestyle are prerequisites for the prevention of influenza infection.

Perform hand hygiene properly Hand hygiene is a simple habit for sanitation. When done properly, hand hygiene is the best way to prevent infections from spreading. In general, we should wash hands with soap and water when hands are visibly dirty or visible soiled with blood, body fluid, after using the toilet or changing the diapers. When hands are not visibly soiled, 70 to 80% alcohol-based handrub (either containing ethanol, isopropanol or n-propanol, or a combination of two of these products) is also an effective alternative. Individuals should perform hand hygiene in the following situations: (1) Before and after touching eyes, nose and mouth; (2) Before eating and preparing food; (3) After using the toilet; (4) After coughing or sneezing; (5) After touching public equipment; or (6) Before and after visiting hospitals, residential care homes or caring for the sick (Figure 1).

Proper hand hygiene technique, either hand washing with liquid soap or using alcohol-based handrub, should follow the seven steps and rub all surfaces of hands and fingers for at least 20 seconds (Figure 2).

1. Clean hands with liquid soap and water: a) Wet hands under running water; b) Apply liquid soap and rub hands together to make a soapy lather; c) Away from the running water, rub the palms, back of hands, between fingers, back of fingers, thumbs, finger tips and wrists. Do this for at least 20 seconds; d) Rinse hands thoroughly under running water; Figure 1 - When to wash our hands. e) Dry hands thoroughly with a clean cotton towel, a paper towel, or a hand dryer; and (Source: Centre for Health Protection (CHP) of the Department of Health (DH). Available from https:// f) The cleaned hands should not touch the water tap directly again. The tap may be www.chp.gov.hk/files/jpg/08657-doh-pr2-r05.jpg.) turned off by using the paper towel wrapping the faucet; or after splashing water to clean the faucet. (Video available from https://www.chp.gov.hk/files/media/hand_washing_eng.mp4 )

COMMUNICABLE DISEASES WATCH 11 Jan 28 - Feb 10 2018 WEEKS 5 - 6 VOL 15 ISSUE NO 3 2. Clean hands with alcohol-based handrub: a) Apply a palmful of alcohol-based handrub and cover all surfaces of the hands; b) Rub the palms, back of hands, between fingers, back of fingers, thumbs, finger tips and wrists; and c) Rub for at least 20 seconds until the hands are dry. (Video available from https://www.chp.gov.hk/files/media/hand_rubbing_eng.mp4 )

Maintain respiratory hygiene Respiratory hygiene can be maintained by observance of cough manners, and proper use of face mask (Figure 3). Face mask provides a physical barrier to fluids and large particle droplets. Surgical mask is a type of face mask commonly used. When used properly, masks can prevent infections transmitted by respiratory droplets. Individuals should wear a mask when (1) they have respiratory infection; (2) need to care for a person with respiratory infection; or (3) when visiting clinics or hospitals during peak season for influenza in order to reduce the risk of infection spread.

Points to note on wearing and removing a surgical mask: ✦ Choose the appropriate mask size. Child size is available for selection as indicated; Figure 2 - Hand Hygiene Technique. ✦ Perform hand hygiene before putting on a mask; (Source: CHP of DH. Available from ✦ The mask should fit snugly over the face: https://www.chp.gov.hk/en/resources/ 1. The coloured side of the mask face outwards with the metallic strip uppermost. For e_health_topics/images/2867.html? those masks without a coloured side, the side with folds facing downwards on the imageid=37394.) outside, and with the metallic clip uppermost (Image 1). 2. For tie-on surgical mask, secure upper tie at the crown of head. Then secure lower tie at the nape (Image 2). For ear-loops type, position the elastic bands around both ears. 3. Extend the mask to fully cover mouth, nose and chin (Image 3). 4. Mould the metallic strip over nose bridge and mask should fit snugly over the face (Image 4). ✦ Avoid touching the mask after wearing. Otherwise, should perform hand hygiene before and after touching the mask; ✦ When taking off tie-on surgical mask, unfasten the tie at the nape first; then unfasten the tie at the crown of head (Image 5). For ear-loops type, hold both the ear loop and take-off gently from face. Avoid touching the outside of face mask during taking-off as it may be covered with germs; ✦ After taking off the surgical mask, discard in a lidded rubbish bin and perform hand hygiene; and ✦ Change surgical mask at least daily. Replace the mask immediately if it is damaged or soiled. (Video available from https://www.chp.gov.hk/files/media/surgical_mask_eng.mp4 )

Figure 3 - Maintain Cough Manner. (Source: CHP of DH. Available from https://www.chp.gov.hk/files/her/ maintain_cough_manner.pdf.)

(Source: CHP of DH. Available from https://www.chp.gov.hk/files/pdf/use_mask_properly.pdf.)

Adopt healthy lifestyle Building up host immunity by having a well-balanced diet, adequate rest and sleep, regular exercise, being a non-smoker and avoiding alcohol consumption are vital to prevent influenza infection. When influenza is prevalent, individuals are advised to avoid going to crowded or poorly ventilated public places. High-risk individuals may consider putting on surgical masks in such places. Last but not the least, individuals should seek medical advice promptly if influenza-like symptoms develop so that appropriate treatment can be initiated as early as possible.

Environmental hygiene Since influenza viruses can survive in the environment for a period of time, it is essential to maintain good environmental hygiene in order to minimise the transmission of influenza through contaminated environment.

The environmental surfaces (e.g. floor) should be cleaned regularly. For frequently touched surfaces (e.g. furniture, toys, utensils), it should be cleaned and disinfected at least daily by using appropriate disinfectant (e.g. one part of household bleach containing 5.25% sodium hypochlorite in 99 parts of water for non-metallic surfaces or 70% alcohol for metallic surfaces), wait for 15 to 30 minutes, and then rinse with water and wipe dry. If places are contaminated by respiratory secretions, vomitus or excreta, use strong absorbent disposable towels to wipe them away. Then the surface and the neighbouring area should be disinfected with

COMMUNICABLE DISEASES WATCH 12 Jan 28 - Feb 10 2018 WEEKS 5 - 6 VOL 15 ISSUE NO 3 appropriate disinfectant (e.g. one part of household bleach containing 5.25% sodium hypochlorite in 49 parts of water for non-metallic surfaces or 70% alcohol for metallic surfaces), leave for 15 to 30 minutes, and then rinse with water and wipe dry.

To maintain good indoor ventilation, windows can be kept open for good indoor ventilation as far as possible. Fans or exhaust fans can be used to improve indoor ventilation. The air-conditioners should also be well-maintained by cleaning the dust-filters of air-conditioners regularly.

For more detail information on seasonal influenza, please visit CHP website: https://www.chp.gov.hk/en/healthtopics/content/24/29.html.

Review of acute gastroenteritis outbreaks associated with sapovirus in Hong Kong Reported by Dr KONG Wai-chi, Scientific Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Facts on sapovirus Sapovirus is primarily transmitted through the faecal-oral route. Sapovirus can be transmitted by food or water contaminated with the virus, by contact with the vomitus or faeces from infected persons or by contact with contaminated objects. Shedding of sapovirus in faeces may continue for weeks after symptoms disappear2. The incubation period usually ranges from less than one day to four days2. Symptoms include vomiting, diarrhoea, nausea, abdominal cramps, chills, headache, myalgia and malaise. Gastroenteritis symptoms are self-limiting and patients usually recover within a few days2. Sapovirus infection could sometimes result in hospitalisation. Patients should be managed with supportive treatment and they should take adequate fluids to prevent dehydration.

Sapovirus was named after an outbreak of acute infectious diarrhoea that occurred in an infant home in the city of Sapporo, Japan in 19771. Sapovirus is a single-stranded RNA virus that belongs to the family Calicivirida2. It has been detected in and environmental water samples2. Sapovirus can cause acute gastroenteritis (AGE) in children and adults. AGE outbreaks due to sapovirus have been reported in various settings such as child care centres (CCCs), kindergartens (KGs), nursing homes, restaurants and schools2.

Although AGE outbreaks associated with sapovirus were less common than that associated with norovirus, sapovirus AGE outbreaks have been reported in various countries and areas worldwide. Suspected foodborne sapovirus outbreaks have also been reported2.

In Hong Kong, the Centre for Health Protection (CHP) of the Department of Health recorded a total of 182 outbreaks of AGE in 2017 based on voluntary reporting by institutions and schools. Sapovirus was associated with two (1.1%) institutional AGE outbreaks in 2017. No AGE outbreak associated with sapovirus was recorded in 2018 (as of February 12).

The two outbreaks recorded in 2017 involved a KG and a special CCC which provided services for children with disabilities. The outbreak in the KG affected eight students and one staff member. The stool specimen collected from one affected student was tested positive for sapovirus. The outbreak in the special CCC affected nine students and eight staff members. The stool specimens collected from two affected students were tested positive for sapovirus. The ages of the 26 patients in the two outbreaks ranged from three to 50 years and 15 (58%) of them were female. Among all patients, the majority (19, 73.1%) presented with diarrhoea, followed by vomiting (12, 46.2%) and fever (1, 3.8%). None of the patients in the two outbreaks required hospitalisation and no death was recorded.

The Public Health Laboratory Services Branch of CHP undertakes laboratory testing for gastroenteritis viruses. Laboratory data showed that from May 2017 to January 2018, the monthly percentage of faecal specimens tested positive for sapovirus ranged from 0.74% to 6.33% (https://www.chp.gov.hk/en/statistics/data/10/641/717/3957.html).

No vaccine for sapovirus infection is available. To prevent sapovirus infection, members of the public are reminded to observe good personal, food and environmental hygiene as follows:

Maintain good personal hygiene ✦ Wash hands thoroughly with liquid soap and water before handling food or eating, and after using the toilet or handling vomitus or faecal matter; ✦ Refrain from work or school, and seek medical advice if suffering from fever, vomiting or diarrhoea; and ✦ Exclude infected persons and asymptomatic carriers from handling food and from providing care to children, elderly and immunocompromised people.

Maintain good food hygiene ✦ Adopt the Five Keys to Food Safety in handling food: 1. Choose (Choose safe raw materials); 2. Clean (Keep hands and utensils clean); 3. Separate (Separate raw and cooked food); 4. Cook (Cook thoroughly); and 5. Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases.

COMMUNICABLE DISEASES WATCH 13 Jan 28 - Feb 10 2018 WEEKS 5 - 6 VOL 15 ISSUE NO 3 Maintain good environmental hygiene ✦ Maintain good indoor ventilation; ✦ Cleanse vomitus/ faeces and disinfect the contaminated areas properly and immediately. Keep other people away from the contaminated areas during cleansing; ✦ Wear gloves and a surgical mask while disposing of or handling vomitus and faeces, and wash hands thoroughly afterwards; ✦ Maintain proper sanitary facilities and drainage system; and ✦ Cleanse and disinfect toilets used by infected person and the soiled areas. Further information on sapovirus is available on the CHP website at https://www.chp.gov.hk/en/resources/464/100203.html.

References 1Chiba S, Sakuma Y, Kogasaka R, et al. An outbreak of gastroenteritis associated with calicivirus in an infant home. J Med Virol 1979;4:249-54. 2Oka T, Wang Q, Katayama K, Saif LJ. Comprehensive review of human sapoviruses. Clin Microbiol Rev 2015;28:32-53.

NEWS IN BRIEF Interim estimates of 2017/18 seasonal influenza vaccine effectiveness in local primary healthcare setting Starting from the 2017/18 influenza season, the Centre for Health Protection (CHP) of the Department of Health has collaborated with private medical practitioners (PMPs) participating in our sentinel surveillance system to estimate the effectiveness of seasonal influenza vaccine (SIV). PMPs are encouraged to collect respiratory specimens from patients presenting with influenza-like illness (ILI) attending their clinics and obtain their vaccination history for the 2017/18 SIV. The respiratory specimens are sent for testing of influenza and other respiratory viruses by the Public Health Laboratory Services Branch (PHLSB). Test-negative case control method is used to estimate the vaccine effectiveness. During the period from November 2017 to January 2018, 313 ILI patients had respiratory specimens collected and analysed, with 179 (57%) tested positive for influenza by PHLSB. About 10% (19/179) of the cases (i.e. patient tested positive for influenza) and 16% (22/134) of the controls (i.e. patients tested negative for influenza) had received the 2017/18 SIV respectively. This gave an interim vaccine effectiveness of about 40% against laboratory-confirmed influenza infection in local primary care setting. CHP will continue to work with PMPs to monitor the effectiveness of SIV. Two probable cases of sporadic Creutzfeldt-Jakob disease CHP recorded two probable cases of sporadic Creutzfeldt-Jakob disease (CJD) in early February, 2018. The first case was a 67-year-old woman with underlying illnesses. She presented with progressive memory loss since mid-January and was admitted to a public hospital on January 25. She was found to have progressive dementia, visual and cerebellar disturbance and extrapyramidal dysfunction. Findings of magnetic resonance imaging of the brain and electroencephalography were compatible with CJD. The second case was a 65-year-old woman with underlying illness. She presented with progressive cognitive decline and delusion since early January 2018 and was admitted to a public hospital on January 10. She was found to have myoclonus, truncal ataxia, dysdiadochokinesia, rigidity and akinetic mutism. Findings of magnetic resonance imaging of the brain and electroencephalography were compatible with CJD. Both cases had no known family history of CJD and no risk factors for either iatrogenic or variant CJD were identified. Both were classified as probable cases of sporadic CJD.

CA-MRSA cases in January 2018 In January 2018, CHP recorded a total of 86 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 53 males and 33 females with ages ranging from 16 days to 92 years (median: 33.5 years). Among them, there were 60 Chinese, 9 Filipinos, 4 Pakistani, 3 Caucasian, 2 Indonesian, 1 African and 7 of unknown ethnicity. Eighty-four cases presented with uncomplicated skin and soft tissue infections while the remaining two cases had severe CA-MRSA infections. The first severe case affected an 89-year-old man with underlying medical illnesses. He presented with productive cough since December 29, 2017. He attended a private hospital on January 5 and was diagnosed to have pneumonia. He was treated with antibiotics in outpatient setting. On January 10, he was admitted to the private hospital for management of underlying illnesses. A chest X-ray taken after admission showed pneumonic changes. His sputum collected after disease onset was cultured positive for CA-MRSA. He remained in a stable condition and was discharged on January 11.

The second severe case affected a 12-year-old boy with good past health. He presented with right middle finger swelling since January 3 after a crush injury. He attended the Accident & Emergency Department of a public hospital on January 7 and was admitted on the same day. X-ray of his right middle finger showed features of osteomyelitis. He was treated with antibiotics, incision and drainage of abscess and debridement of necrotic tissue of his right middle finger. Pus from the deep abscess and necrotic bone tissue of his right middle finger were both cultured positive for CA-MRSA. He was discharged on January 24. Among the 86 cases, one was a nurse working in a private hospital. Investigation did not reveal any epidemiologically linked cases. Besides, four household clusters, with each affecting two persons, were identified in January.

Scarlet fever update (January 1, 2018 – January 31, 2018) Scarlet fever activity in January was similar to that in December and still remained at a high level. CHP recorded 410 cases of scarlet fever in January as compared with 412 cases in December. The cases recorded in January included 239 males and 171 females aged between nine months and 38 years (median: six years). There were 16 institutional clusters occurring in 14 kindergartens/child care centres and two primary schools, affecting a total of 40 children. No fatal cases were reported in January. In view of the high level of scarlet fever activity, parents have to take extra care of their children in maintaining strict personal, hand and environmental hygiene. Scarlet fever can be effectively treated with antibiotics. People presenting with symptoms of scarlet fever (such as fever, sore throat and skin rash) should consult a doctor promptly for early diagnosis and treatment. Besides, children suffering from scarlet fever should refrain from attending school or child care setting until fever has subsided and they have been treated with antibiotics for at least 24 hours.

COMMUNICABLE DISEASES WATCH 14 Feb 11 - Feb 24 2018 WEEKS 7 - 8 VOL 15 ISSUE NO 4

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected]

FEATURE IN FOCUS 2017 Year in Review Reported by Surveillance Section, Communicable Disease Division, Surveillance and Epidemiology Branch, CHP. In this issue, we reviewed communicable diseases and issues of public health concern in 2017... Avian influenza In 2017, the Centre for Health Protection (CHP) of the Department of Health (DH) has recorded three human cases of avian influenza A(H7N9), including a 10 year-old boy and two males aged 62 and 76 years. All were imported infections from Mainland China (two from Guangdong province (廣東省 ) and one from Fujian province (福建省) ). They had onset of illness between January and March during which the activity of avian influenza A(H7N9) in the Mainland was high. The two adult patients had pneumonia while the 10-year-old boy presented with upper respiratory tract infection. The 62-year–old man who had history of chronic obstructive airway disease, diabetes and other pre-existing chronic medical illnesses died while the other two patients had recovered. Epidemiological investigation revealed that two patients had visited wet markets or exposure to environments with poultry during the incubation period while the exposure history of the fatal case remained unknown. Extensive contact tracing did not identify any secondary cases.Apart from human infections, there were three local reports of detection of avian influenza A(H5N6) in dead birds, including a red-whiskered bulbul found in Kowloon City in April, an Oriental magpie robin found in Tseung Kwan O and a black-faced spoonbill found in the Hong Kong Wetland Park in Tin Shui Wai in December. Contact tracing of the persons with unprotected exposure to the dead birds did not identify any human infection.

Chickenpox In 2017, a total of 9 353 cases of were recorded by CHP, slightly more than 8 747 and 8 879 cases recorded in 2015 and 2016 respectively. In the past, the annual incidence exhibited a cyclical pattern with peaks observed every four to five years. The incidence remained stable from 2015 to 2017 (120 to 127 per 100 000 population) after the introduction of the varicella vaccine into the Hong Kong Childhood Immunisation Programme (HKCIP) in July 2014 for children born in 2013 or after (Figure 1). The universal varicella vaccination has brought about Figure 1 - Annual incidence of varicella in Hong Kong, 1999 to 2017. an upward shift of the age of the cases. Before 2014, the incidence among children aged one to five years was much higher than other age groups, but a substantial decrease was noted from 2015 to 2017. However, increase in incidence was observed in children aged six to 11 years with the present cohort not eligible for universal varicella vaccination, surpassing that among children aged one to five years in the past two years. Similar to 2016, the highest incidence in 2017 was observed in children aged six to 11 years (1 285 per 100 000), followed by children aged one to five years (708 per 100 000). The gap between the incidences in these two age groups has further widened in 2017 (Figure 2a). For adults, there was also an apparent increase in incidence, although incidence remained much lower than children (Figure 2b).

Figure 2a - Age-specific incidence of varicella among children (aged less Figure 2b - Age-specific incidence of varicella among adults (aged 18 than 18 years) in Hong Kong, 1999 to 2017. years and above) in Hong Kong, 1999 to 2017. COMMUNICABLE DISEASES WATCH 15 Feb 11 - Feb 24 2018 WEEKS 7 - 8 VOL 15 ISSUE NO 4 Dengue fever CHP recorded 102 dengue fever cases in 2017 as compared with a range of 103 to 124 cases per year between 2013 and 2016 (Figure 3). The cases involved 58 males and 44 females, with ages ranging from six to 84 years (median: 34 years). Among them, fever was the most common symptom (100, 98.0%), followed by headache (68, 66.7%) and myalgia (63, 61.8%). Other symptoms included rash (42, 41.2%), eye pain (32, 31.4%) and (28, 27.5%). Eighty-two patients (80.4%) required hospitalisation and one of them had severe dengue. All patients recovered and no fatal case was recorded. Figure 3 - Annual number of dengue fever cases from 2008 to 2017. One hundred and one cases were imported infections. Among the 92 imported cases with place of infection determined, the patients had travelled to dengue affected countries and areas including Thailand (20), the Philippines (13), Sri Lanka (12), Vietnam (12), Indonesia (8), India (6), Malaysia (5), the Maldives (5), Mainland China (3), Myanmar (3), Cambodia (2), Laos (1), Nepal (1) and Singapore (1).Among the remaining nine imported cases, the patients had travelled to multiple countries during the incubation period. One locally acquired infection was recorded in August affecting a 45-year-old man who lived in Prince Edward and worked in a construction site in West Kowloon. No epidemiologically-linked case was identified.

Hantavirus infection In 2017, CHP recorded two cases of hantavirus infection, affecting two males, aged 22 and 32. One case was classified as locally acquired infection whereas the infection source for the other could not be determined as he spent part of the incubation both in and outside Hong Kong but no high risk exposure was identified in both places. For the locally acquired infection, rodent activities were detected in the vicinity of the patient’s residence and school. Both patients presented with fever, vomiting and abdominal pain, and were found to have acute renal failure and thrombocytopenia.They remained in stable condition and had recovered after treatment.

Hepatitis A outbreak among men who have sex with men An outbreak of hepatitis A among men who have sex with men (MSM) in Hong Kong started in September 2015 and continued through 2016 and 2017. As of December 31, 2017, a total of 54 hepatitis A cases affecting MSM aged from 20 to 55 had been recorded since September 2015, with 37 known to be positive for human virus (HIV).To control the outbreak, hepatitis A vaccination was arranged in early 2017 for some 2 000 MSM who were followed up at the HIV clinics of DH and the Hospital Authority. Hepatitis A vaccination was also offered to MSM attending designated Social Hygiene Clinics.This vaccination campaign had led to a marked decrease in the number of hepatitis A cases among MSM to a low level in the second half of 2017. Only four cases were reported since August 2017 as compared with about six cases per month during the first quarter of 2017.

Invasive Pneumococcal Disease CHP recorded 186 cases of invasive pneumococcal disease (IPD) in 2017, which was comparable to that in 2016 (189). Under CHP’s laboratory surveillance and statutory notification systems1, the overall annual incidence of IPD ranged from 1.7 to 2.9 per 100 000 from 2007 to 2017 (Figure 4). Since introduction of pneumococcal conjugate vaccines (PCV) into HKCIP, the incidence of IPD caused by the seven serotypes covered in PCV7/10/132 has been on a decline. On the other hand, the Figure 4 - IPD incidence in Hong Kong by serotype groups, 2007 to 2017. incidence of IPD caused by the six serotypes that are covered by (Note: 2007 to 2014: Public Health Laboratory Services Branch laboratory PCV13 but not by PCV7 have increased since 2010. surveillance (bacterial culture only);2015 onwards:IPD notification to CHP (bacterial culture + PCR)). Japanese In 2017, CHP recorded five cases of Japanese encephalitis (JE) as compared with a range of two to six cases per year between 2013 and 2016. All the cases in 2017 were locally acquired infection (Figure 5). All five patients were male and their ages ranged from 38 to 69 years (median: 59 years). Four cases were mosquito-borne and one blood-borne.

Figure 5 - Annual number of JE cases from 2008 to 2017.

1IPD was listed as a notifiable infectious disease under the Prevention and Control of Disease Ordinance (Cap 599) in 2015. 2There are more than 90 serotypes of pneumococci and existing pneumococcal vaccines covered different serotypes.

COMMUNICABLE DISEASES WATCH 16 Feb 11 - Feb 24 2018 WEEKS 7 - 8 VOL 15 ISSUE NO 4 Among the four mosquito-borne cases, two patients lived in Tin Shui (I) Estate and Tin Shui (II) Estate in Tin Shui Wai respectively, where there were pig farms within two km of their homes.The other two patients lived in Sai Kung and Eastern District respectively, where there was no pig farm within two km of their homes.

The blood-borne case recorded in July 2017 involved a 52-year-old man who was admitted to a public hospital in May 2017 for organ transplant for his underlying disease. He developed fever and decreased consciousness on July 6 and was tested positive for JE on July 20. He received multiple blood transfusions during the incubation period. Laboratory investigation revealed that the residual sample of the blood transfused to the patient on June 22 was tested positive for JE virus. The patient passed away due to JE in October. The concerned blood was donated by a man on May 29. He resided in Kingswood Villas in Tin Shui Wai and remained asymptomatic all along before and after the blood donation.

Legionnaires’ disease In 2017, CHP recorded a total of 72 cases of Legionnaires’ disease (LD) as compared with 76 cases and 66 cases in 2016 and 2015 respectively. The characteristics of the cases remained similar to those recorded in the past. Among the 72 cases, 70 were Chinese and the remaining two cases involved an Australian and a British. Their ages ranged between 39 and 99 years (median: 68 years). Males were predominately affected with a male to female ratio of 5:1. All patients developed pneumonia requiring hospitalisation and 29 patients (40.3%) required admission to intensive care unit. Nine patients died within the same admission for LD (seven due to LD and the other two due to concomitant diseases). Most cases were initially diagnosed by urinary antigen test (61, 84.7%) and polymerase chain reaction of respiratory specimens (10, 13.9%), while the remaining case (1.4%) was initially diagnosed by culture of respiratory specimen. Fifty-one cases (70.8%) and 10 cases (13.9%) were classified as locally acquired and imported infections respectively, while the place of infection of the remaining 11 cases (15.3%) could not be determined because the patients had stayed both inside and outside Hong Kong during their incubation periods (IP). Among the imported cases, there were three epidemiologically linked cases involving three patients who had stayed in or visited the same hotel in Macau during the IP. Among the 51 local cases, their residential places during the IP were distributed in various districts in Hong Kong. Environmental investigations were undertaken and environmental samples were collected for 12 locally acquired cases according the latest strategy. Except for a nosocomial case found to be related to tap water in the hospital ward, the sources of infection of the remaining 11 cases could not be confirmed after environmental investigations.

Leptospirosis In 2017, CHP recorded a total of five cases of leptospirosis, affecting two males and three females, with ages ranging from 23 to 68 years. All of the cases were classified as locally acquired infection. Signs of rat infestation were observed in the vicinity of the residence or workplace of all the patients. One patient who worked as an outdoor coach reported to have an abrasion injury while swimming in countryside during the incubation period. The other four patients could not recall any high risk exposure (such as water sports, hiking, etc.) during the incubation period. No fatalities were recorded in 2017.

Pertussis In Hong Kong, pertussis follows a cyclic pattern with peaks occurring every three to five years. During 2017, a total of 69 laboratory confirmed cases of pertussis were recorded by CHP, surpassing the previous peak of 50 cases in 2015 (Figure 6). Similar increases were also observed in other areas such as Mainland China and New Zealand. Among the 69 cases, 62 (94%) were classified as locally acquired infection while five were imported infection from Mainland China (4) and India (1). The place of infection of two cases was undetermined as the patients had stayed both in and outside Hong Kong during the incubation period. No pertussis-related deaths were recorded. Overall, the cases ranged in age from 20 days to 81 years with a median age of five years. Forty of them were female (58%). Children aged below Figure 6 - Number of pertussis notifications by year,2004 to 2017. 18 years remained the most affected age group (35 cases, 51%), particularly those less than six months of age (30 cases, 43%) who had either not yet received or completed the three-dose primary series of diphtheria, and pertussis (DTaP) vaccination, including 17 (25%) who were under two months old and had not reached the recommended age for the first dose of DTaP vaccine under HKCIP. During 2017, an increasing proportion of pertussis cases (34 cases, 49%) has been observed among adults, compared with an average of 34% in 2015 and 29% in 2016. Most of them were either unvaccinated or had uncertain immunisation status. Nearly one-third of these adult cases (10 cases, 29%) were identified during investigation following the diagnosis of an infant pertussis case in the same household.There were seven clusters of pertussis reported during 2017, involving 17 cases. The clusters were generally small in size (each affecting two to three persons) and all occurred in household settings, mostly among infants, their family members and other household contacts.

COMMUNICABLE DISEASES WATCH 17 Feb 11 - Feb 24 2018 WEEKS 7 - 8 VOL 15 ISSUE NO 4 Scarlet fever (SF) In 2017, CHP recorded a total of 2 354 cases of SF which was the highest annual number ever recorded and a significant increase as compared with a range of about 1 100 and 1 500 cases per year between 2012 and 2016. Unlike the seasonal pattern in the past few years in which the activity of SF was higher from May to June and from November to March, SF activity remained at an elevated level most of the time in 2017 with low activity recorded only during August and September (Figure 7). Although there was a marked increase in the number of reported cases in 2017, the epidemiological characteristics were similar to those reported in previous years. Their ages ranged from two months to 49 years (median: five years) with the majority (96%) affecting children aged ten years or below.The male-to-female ratio was 1.5:1. Eight hundred and Figure 7 - Monthly number of scarlet fever cases recorded in 2017. ten cases (34%) required hospitalisation. Two cases aged five and ten years developed severe complications ( and septic shock respectively). No fatal cases were recorded in 2017. Most cases (91%) were sporadic infection while 221 cases were involved in a total of 96 clusters. These included 71 school/ institutional clusters (46 kindergartens/ child care centres, 24 primary schools and one special school) and 25 home clusters.The number of persons affected in each cluster ranged from two to six persons (median: two persons).

Seasonal influenza The epidemiological pattern of seasonal influenza in 2017 was atypical. In Hong Kong, the major influenza season was usually the winter season occurring in the first few months. In 2017, the winter influenza season was a mild season with a modest increase in influenza activity between late February and early April, which lasted about seven weeks. It was shorter than the 2014/15 and the 2015/16 winter seasons which lasted about four months.The predominating circulating virus was influenza A(H3N2).

In contrast, the summer influenza season was an unusually severe season. It arrived in mid-May, which started earlier than typical summer seasons in the past.After several weeks of steady increase, the influenza activity sharply increased in early July and reached a very high level in mid-July with some surveillance parameters (e.g. influenza-associated hospitalisation rates in public hospitals) exceeding the highest levels recorded in recent years. This summer season lasted for about 16 weeks until late August. Influenza A(H3N2) continued to be the predominating virus.

CHP recorded 66 (including 41 deaths) and 582 cases (including 430 deaths) of intensive care unit admissions or deaths with laboratory confirmation of influenza among adult patients through the enhanced surveillance during the winter and summer season respectively. Among these 648 cases, 514 (79.3%) affected elderly aged 65 years or above. Most (83.2%) had pre- existing chronic medical diseases. The characteristics were similar to those recorded in previous seasons predominated by influenza A(H3N2).

In 2017, 27 cases (including four deaths) of paediatric influenza-associated severe complication/ death were recorded among patients aged below 18 years, as compared to 31 and 25 cases in 2016 and 2015 respectively. The cumulative incidences (per 100 000 population) among children aged zero to five years, six to 11 years and 12 to 17 years were 5.59, 1.16 and 0.61 respectively.Among these 27 paediatric cases, eight cases (29.6%) had pre-existing chronic diseases.Twenty-four cases (88.9%) did not receive the season influenza vaccine for the 2016/17 season.

NEWS IN BRIEF

A probable case of sporadic Creutzfeldt-Jakob disease

The Centre for Health Protection recorded a probable case of sporadic Creutzfeldt-Jakob disease (CJD) on February 13, 2018, affecting a 63 year-old woman with underlying illnesses. She presented with dizziness, vertigo and blurred vision on December 6, 2017. Later, she developed right-sided numbness and slurred speech and was hospitalised at a public hospital on December 23 to 27, 2017 where she was treated as ischemic stroke. Subsequently, she was admitted to the same public hospital on January 16, 2018 for rapidly progressive dementia and impaired coordination. After admission, she was noted to have cerebellar signs, myoclonus and akinetic mutism. Findings of electroencephalography were compatible with CJD. Her condition was stable. No risk factors for either iatrogenic or variant CJD were identified. She was classified as a probable case of sporadic CJD.

COMMUNICABLE DISEASES WATCH 18 Feb 25 - Mar 10 2018 WEEKS 9 - 10 VOL 15 ISSUE NO 5

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Update on Psittacosis Reported by Dr Ashley FONG, Medical and Health Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP.

Psittacosis, also known as parrot fever or ornithosis, is an infectious disease caused by the bacteria Chlamydophila psittaci (C. psittaci), which primarily affect birds.The infection is usually transmitted to humans through inhalation of C. psittaci from dried droppings or secretions of infected birds.Although all birds can transmit the disease to human, pet birds (e.g. parrots, cockatiels, parakeets and macaws) and poultry (turkeys and ducks) are most frequently involved. Psittacosis is not normally transmitted from person to person. In humans, psittacosis commonly presents as influenza-like illness or pneumonia. Symptoms include fever, headache, rash, muscle pain, chills and dry cough. Occasionally, complications such as encephalitis, endocarditis, myocarditis, hepatitis or sepsis may occur. The incubation period typically ranges from five to 14 days, but may be up to four weeks. Psittacosis can be effectively treated with appropriate antibiotics. In birds, infection with C. psittaci is known as avian chlamydiosis. It can cause conjunctivitis, enteritis, air sacculitis, pneumonitis, and hepatosplenomegaly in psittacine birds. Symptoms in birds may include eye or nasal discharge, diarrhoea, loss of appetite and emaciation. However, apparently healthy birds can be carriers and shed the bacteria, particularly when they are subjected to stress through crowding and shipping.

In Hong Kong, psittacosis has been listed as a notifiable disease under the Prevention and Control of Disease Ordinance (Cap 599) since July 14, 2008.We reviewed the confirmed cases recorded by the Centre for Health Protection (CHP) of the Department of Health in the past five years. Since 2013, CHP recorded a total of 32 cases of psittacosis (as of March 10, 2018). Between 2013 and 2017, the annual number of cases ranged from two to nine cases (Figure 1). So far, five cases have been recorded in 2018 (as of March 10). All the 32 cases were diagnosed by polymerase chain reaction (PCR). The male-to-female ratio was 2.2:1.Their ages ranged from 34 to 80 years with a median of 61.5 years (Figure 2). Among them, 20 (62.5%) were locally acquired infections and seven (21.9%) were imported infections. The remaining five patients (15.6%) had stayed both inside and outside Hong Kong during their incubation period and no obvious contact with birds could be identified so the places of infection were undetermined.

The most common clinical presentations included cough (29, 90.6%), fever (28, 87.5%) Figure 1 - Annual number of psittacosis cases recorded and shortness of breath (17, 53.1%). All patients had pneumonia and required in Hong Kong, 2013-2018 (as of March 10, 2018). hospitalisation with 15 patients (46.9%) requiring admission to intensive care units (ICU) and one (3.1%) to high dependency unit. Seven patients (21.9%) developed other complications, including acute renal failure, deranged liver and/or renal functions and shock.There was one death due to psittacosis in 2014. Seventeen patients (53.1%) had pre-existing medical conditions. Regarding risk exposure, 14 patients (43.8%) had contact with birds/ bird droppings or history of visiting pet bird shop during the incubation period.Among them, swabs from birds and environment were available for testing in four cases. All were tested negative for C. psittaci except for two cases involved in a cluster in 2018 detailed below. The remaining 18 patients (56.3%) could not recall any known exposure to birds prior to Figure 2 – Age distribution of psittacosis cases recorded their disease onset. in Hong Kong, 2013-2018 (as of March 10, 2018). Thirty cases (93.8%) were sporadic cases without epidemiological linkage.Two cases in 2018 were involved in a household cluster affecting a couple aged 51 and 54 years old. Both patients had good past health. The 51-year-old woman presented with fever, productive cough, shortness of breath and malaise in late January. Her 54-year-old husband presented with fever, headache and myalgia on February 4.They had no travel history within the incubation period. Investigation revealed that they had visited the bird market on January 14 and 21, and bought a parrot from a bird shop there on January 21. A cloacal swab and a conjunctival swab

COMMUNICABLE DISEASES WATCH 19 Feb 25 - Mar 10 2018 WEEKS 9 - 10 VOL 15 ISSUE NO 5 taken from the parrot and an environmental swab taken from the box used to keep the parrot were all tested positive for C. psittaci by PCR.Their household contacts and the persons who had contact with the parrot and the workers of the bird shop all remained asymptomatic. To prevent psittacosis, the public is advised to: ❖ Maintain good personal and environmental hygiene; ❖ Wash hands thoroughly after handling birds; and ❖ Seek medical treatment if symptoms develop. People keeping birds as pets are advised to: ❖ Purchase birds from licensed animal traders; never buy pets from suspicious or unknown sources; ❖ Position cages so that food, feathers, and faeces cannot spread between them (i.e. do not stack cages, use solid-sided cases or barriers if cages are next to each other); ❖ Disinfect bird cage and surfaces contaminated by bird droppings or secretions regularly; ❖ Avoid over-crowding of birds; ❖ Isolate and treat infected birds; ❖ Avoid close contact with infected birds; and ❖ Wear gloves and a surgical mask when handling droppings or secretions of infected birds. Review of hantavirus infection in Hong Kong Reported by Dr Eric LAM, Medical and Health Officer, Communicable Disease Surveillance and Intelligence Office, Surveillance and Epidemiology Branch, CHP.

Hantavirus infection is a zoonotic disease caused by hantaviruses which belong to the bunyavirus family1. Hantaviruses are present throughout the world and are normally carried by rodents, such as rats, mice and moles2. Hantavirus is mainly transmitted to humans through inhalation of the virus in aerosolised excreta of infected rodents, which will carry and secrete infectious virus for prolonged periods, probably for life2. It could also be transmitted indirectly through contact with the urine, droppings or saliva of infected rodents, consumption of the food contaminated by these matters, touching the eyes, nose or mouth after contacting articles contaminated likewise, or through bites by infected rodents. Some occupations pose an increased risk of contracting hantavirus, such as forestry workers, farmers and those that involve handling of rodents, entering and cleaning long abandoned buildings, etc3. Human-to-human transmission is extremely rare. Hantavirus can cause a range of diseases in humans, from mild, flu-like illness to severe respiratory illness or haemorrhagic disease with kidney involvement, known as Hantavirus Pulmonary Syndrome (HPS) and Haemorrhagic Fever with Renal Syndrome (HFRS) respectively. Symptoms may start to develop around one to eight weeks after exposure1. Early symptoms include fever, fatigue and muscle-ache. There may also be headache, dizziness, chills and gastrointestinal symptoms such as nausea, vomiting, diarrhoea and abdominal pain. There is no specific treatment for hantavirus infection and supportive therapy is the mainstay of care for patients. HFRS is caused by the Old World Hantaviruses and is reported mostly in Asia and Europe. It could manifest as severe renal impairment, with mortality ranging from less than 1% to 15%1. On the other hand, HPS is caused by the New World Hantaviruses and is largely reported in America. Patients with HPS may develop severe respiratory distress.The disease can be fatal, with a case fatality rate of up to 38%1.

Hantavirus infection has been included in the list of notifiable diseases under the Prevention and Control of Disease Ordinance (Cap 599) since July 14, 2008.All registered medical practitioners are required to notify the Centre for Health Protection (CHP) of the Department of Health of any suspected or confirmed cases of hantavirus infection. Since hantavirus infection became a notifiable disease, CHP recorded a total of six confirmed cases (as of February 28, 2018). The number of cases ranged from zero to two per year (Figure 1) with no obvious seasonality (Figure 2). Five cases (83%) were males.Their ages ranged from 22 to 76 years (median: 37 years) (Figure 3).The majority (4 cases, 67%) acquired the infection locally. One case was an imported infection from Mainland China. For the remaining case, the source of infection could not be determined, as the patient had spent Figure 1 - Number of hantavirus infection reported in Hong Kong part of the incubation period both in and outside Hong Kong. (July 2008* - February 2018^). All of the six cases were HFRS. They all presented with fever. Other symptoms include nausea/vomiting (67%), abdominal pain (67%), diarrhoea (33%), chills and rigor (50%), headache (17%), malaise (17%) and myalgia (17%) (Table 1). All required hospitalisation and one (17%) of them required admission to intensive care unit. Hantavirus infection was confirmed by the detection of hantavirus-specific IgM in blood sample in four cases and a four-fold rise in hantavirus-specific antibody titres between acute and convalescent sera in the remaining two cases. Laboratory investigation revealed that all these patients had deranged renal function and three (50%) of them required haemodialysis. Four patients (67%) developed thrombocytopenia. Other abnormalities include deranged liver function (17%), deranged clotting profile (17%) and haematuria (17%) (Table 2). No fatality was recorded. COMMUNICABLE DISEASES WATCH 20 Feb 25 - Mar 10 2018 WEEKS 9 - 10 VOL 15 ISSUE NO 5 In all four locally acquired infection, rodent activity was found in the places frequented by Table 1 - Clinical presentation of the reported cases the patients concerned during field investigation, including the vicinity of patients’ of hantavirus infection (July 2008 - February 2018).

residence, their workplaces or schools. Health advice on prevention of Hantavirus Flu-like symptoms infection was given to the patients. Rodent control and preventive measures, environmental cleansing and disinfection were stepped up in the concerned areas by the Number of cases % Food and Environmental Hygiene Department, in liaison with relevant parties as Fever 6 100 appropriate.All of the cases were sporadic cases without epidemiological linkage identified. Chills and rigors 3 50

Headache 1 17

Malaise 1 17

Myalgia 1 17

Gastrointestinal symptoms

Nausea/vomiting 4 67

Abdominal pain 4 67

Diarrhoea 2 33 Table 2 - Laboratory findings of the reported cases Figure 2 - Monthly distribution of hantavirus infection in Figure 3 - Age distribution of hantavirus infection in Hong of hantavirus infection (July 2008 - February 2018). Hong Kong (July 2008 - February 2018). Kong (July 2008 - February 2018). Number of % Currently there is no vaccine available for hantavirus.To prevent hantavirus infection, it is cases important to eliminate rodent infestation and maintain good personal and environmental Deranged renal 6 100 hygiene. Members of the public should: function ❖ Wash hands regularly, especially before preparing or eating food and after contact with Thrombocytopenia 4 67 animals; Proteinuria ❖ Store food properly; 2 33 ❖ Keep all refuse and food remnants in rubbish bins fitted with cover; Deranged clotting 1 17 profile ❖ Inspect regularly all flowerbeds and pavements for rodent infestation; Deranged liver 1 17 ❖ Avoid visiting places with poor environmental hygiene when travelling to places with function reported cases of hantavirus infection; and Haematuria ❖ Avoid high-risk activities such as handling rodents with bare hands, entering enclosed 1 17 space infested by rodents, disturbing rodents excreta or nests and keeping wild rodents Leucocytosis 1 17 as pets, etc.

References 1Hantavirus. United States Centers for Disease Control and Prevention.Available at: https://www.cdc.gov/hantavirus/index.html/. 2The characteristics, diagnosis, epidemiology of hantaviruses. Public Health England.Available at: https://www.gov.uk/guidance/hantaviruses. 3Facts about Hantavirus. European Centre for Disease Prevention and Control.Available at: https://ecdc.europa.eu/en/hantavirus-infection/facts.

NEWS IN BRIEF A cluster of pertussis in a public hospital In March 2018, the Centre for Health Protection (CHP) recorded a cluster of pertussis infection affecting three one-month-old babies (two males and one female).They presented with persistent cough from February 25 to March 4 and were admitted to public hospitals for treatment from March 5 to 6.Their nasopharyngeal swabs were tested positive for Bordetella pertussis and they were treated with antibiotics.They remained in stable condition and two babies were discharged. The three babies were not yet due for the first dose of diphtheria, tetanus, acellular pertussis and inactivated poliovirus (DTaP-IPV) vaccine. Chemoprophylaxis was offered to household contacts of the three affected babies. Epidemiological investigation revealed that the trio were born in and stayed in the same cubicle of a postnatal ward during the incubation period from February 12 to 16. Upon contact tracing of staff, mothers, babies and visitors who had stayed or visited the same cubicle, no other laboratory confirmed case was identified at this moment. Infection control measures of the ward have already been stepped up and all concerned staff, mothers, babies and visitors were under medical surveillance. Investigations are on-going. Two local sporadic cases of listeriosis CHP recorded two sporadic cases of listeriosis in early March.The first case was a 60-year-old woman with underlying illness. She was admitted to a public hospital for management of her underlying illness on February 20. She developed fever and shortness of breath on February 26. Her blood culture collected on February 26 yielded both monocytogenes and Group D Salmonella. She was treated with antibiotics. Her condition deteriorated and she passed away on March 1. The second case was an 81-year-old man with underlying illnesses. He presented with fever and worsening of lower limb edema on March 4 and was admitted to a public hospital on the same day.The clinical diagnoses were sepsis and fluid overload. His blood culture collected on March 4 yielded and he was treated with antibiotics. His condition was stable. Both cases had no travel history and did not consume any high-risk food (including Australian rockmelons) during the incubation period. Their household contacts remained asymptomatic. So far, no epidemiological linkage has been identified among these two cases. Investigations are on-going.

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EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Update on the situation of chikungunya fever Reported by Dr Zenith WU, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP. First described during an outbreak in Tanzania in 1952, chikungunya fever (CF) is an acute viral disease caused by the chikungunya virus1. Chikungunya virus is a mosquito-borne RNA alphavirus that can be transmitted to human by the bites of infected female Aedes mosquitoes. CF is characterised by an abrupt onset of fever frequently accompanied by joint pain, which is often very debilitating and lasts for a few days or up to a few weeks. Other common symptoms include muscle pain, headache, nausea, fatigue and skin rash. Most patients recover fully. In some cases, joint pain may persist for several months or even years.

Global situation Since its first identification in 1952, CF has been reported in over 60 countries in Africa, the Americas, Asia and Europe (Figure 1).Among these countries, the habitat suitability for the existence and development of Aedes aegypti and/or Aedes albopictus varied2. Among these countries considered to be suitable for only Aedes albopictus (a mosquito commonly found in Hong Kong), only France had reported autochthonous transmission of CF2,3. The following section reviews the global situation of CF in the past five years.

In Africa, human infections have been at relatively low levels for a number of years but outbreaks were occasionally reported1. In 2015, Senegal reported an active circulation of chikungunya virus in the region of Kédougou, which resulted in ten confirmed CF cases4. In 2016, Kenya reported a large outbreak in Mandera Figure 1 - Countries and territories where chikungunya cases have been reported (as East sub-county with more than 1 700 suspected of April 22, 2016) (Source: Centers for Disease Control and Prevention) cases5. In early 2018, Kenya reported another CF outbreak in Mombasa County which affected 453 cases (including 32 confirmed and 421 suspected cases) as of February 3, 20186. According to the World Health Organization, this was the first time that active circulation of CF was laboratory confirmed in Mombasa County, which is a popular tourist destination. In the Americas, the first outbreak of CF with local transmission was recorded in December 2013, when France reported two laboratory-confirmed autochthonous cases in the French part of the Caribbean island of St. Martin1. Since then, local transmission has been confirmed in over 43 countries and territories in the Americas. The number of confirmed and suspected cases in the Americas in 2017 had decreased by 18.1% and 82.3% respectively when compared to the same period in 20167. In 2017, more than 123 000 confirmed and 61 000 suspected autochthonous transmission cases were reported as of December 22, 20178, with the majority of both the confirmed and suspected cases (98.9% and 81.5% respectively) reported by Brazil.

In Asia, endemic or epidemic CF has been reported in several countries including Cambodia, India, Indonesia, Laos, Malaysia, Maldives, Myanmar, Pakistan, the Philippines, Thailand and Vietnam9. In December 2016, Pakistan reported its first CF outbreak which occurred in Karachi city in the Sindh province10. Between December 19, 2016 and April 14, 2017, a total of 1 419 suspected CF cases were reported in various districts in Karachi10. In addition, the first outbreak in Balochistan province in Pakistan was confirmed in April 2017. As of April 19, 2017, the number of suspected CF cases reported in Balochistan was 1 96210.

In Europe, outbreaks of CF have been reported in several continental countries. In France, two outbreaks with locally-acquired infection were reported in 2014 and 2017 respectively, with each outbreak affecting four confirmed cases11,12. In Italy, an outbreak was reported in June 2017.As of September 26, 2017, 183 CF cases had been notified to the Lazio Region of Italy (109 of which were confirmed and 74 were suspected cases) and three confirmed cases had been notified from other areas with a travel history to the affected part of the Lazio Region13.

COMMUNICABLE DISEASES WATCH 22 Mar 11 - Mar 24 2018 WEEKS 11 - 12 VOL 15 ISSUE NO 6 Local situation In Hong Kong, CF has been listed as a notifiable infectious disease under the Prevention and Control of Disease Ordinance (Cap 599) since March 6, 2009. In the past five years (from 2013 to 2017), the Centre for Health Protection of the Department of Health recorded a total of 17 confirmed sporadic cases, ranging from one to eight cases per year (Figure 2). The cases involved eight males and nine females, with ages ranging from 25 to 77 years (median: 50 years). The majority of the cases presented with fever (100%), joint pain (88.2%) and rash (58.8%). Sixteen cases (94.1%) were diagnosed by detection of chikungunya virus genomic sequences in clinical specimen by polymerase chain reaction and one case (5.9%) was diagnosed by four-fold or greater rise in antibody titres to chikungunya virus antigen in paired serum samples. All cases were imported infections. Among the 17 cases, the patients had travelled to countries and areas Figure 2 - Number of CF cases in Hong Kong from affected by CF including India (7), Indonesia (5) and the Philippines (2). The 2013 to 2018 (*as of March 27, 2018). remaining three patients had travelled to multiple countries during the incubation period. No locally acquired cases were recorded.

Prevention At present, there is no effective vaccine against CF. The best way to prevent CF is to prevent mosquito bites when travelling to endemic areas. Members of the public are advised to wear loose, light-coloured and long-sleeved clothes and long trousers, use insect repellents containing DEET over the exposed parts of the body and clothes, use mosquito screens or nets when the room is not air-conditioned and place mosquito coils or electric mosquito mat/ liquid near possible entrance, such as windows, to prevent mosquito bites. For details about the use of insect repellents, please refer to 'Tips for using insect repellents’ at the following link: http://www.chp.gov.hk/en/view_content/38927.html. If falling sick upon return from endemic areas, travellers should seek medical advice immediately and inform the doctor of their travel history for prompt medical management, epidemiological investigation and control actions.

Moreover, one of the vectors for CF, Aedes albopictus, is present in Hong Kong and could transmit not only CF, but also dengue fever and Zika virus infection. Mosquito prevention and control is important to prevent these mosquito-borne diseases. The public should prevent accumulation of stagnant water, and control vectors and reservoir of the diseases by: ❖ Changing the water in vases once a week; ❖ Clearing the water in the saucers under potted plants every week; ❖ Covering water containers tightly; ❖ Ensuring air-conditioner drip trays are free of stagnant water; ❖ Putting all used cans and bottles into covered dustbins; and ❖ Storing food and dispose of garbage properly.

References 1World Health Organization (2017).Chikungunya.Available at: http://www.who.int/mediacentre/factsheets/fs327/en/, accessed on March 27, 2018. 2Leta S, Beyene T, De Clercq E,Amenu K, Kraemer M, Revie C. Global risk mapping for major diseases transmitted by Aedes aegypti and Aedes albopictus. International Journal of Infectious Diseases. 2018;67:25-35. 3Geographic Distribution. Chikungunya fever. CDC.Available at: https://www.cdc.gov/chikungunya/geo/index.html, accessed on 27 March 2018. 4World Health Organization. Chikungunya - Senegal. Available at: http://www.who.int/csr/don/14-september-2015-chikungunya/en/, accessed on March 27, 2018. 5World Health Organization. Chikungunya - Kenya. Available at: http://www.who.int/csr/don/09-august-2016-chikungunya-kenya/en/, accessed on March 27, 2018. 6World Health Organization. Chikungunya - Mombasa, Kenya. Available at: http://www.who.int/csr/don/27-february-2018-chikungunya-kenya/en/, accessed on March 27, 2018. 7Pan American Health Organization. Number of reported cases of Chikungunya Fever in the Americas - EW 51 (December 22, 2017). Available at: http://www.paho.org/hq/index.php?option=com_docman&task=doc_download&Itemid=270&gid=43280&lang=en, accessed on March 27, 2018. 8Pan American Health Organization. Number of reported cases of Chikungunya Fever in the Americas - EW 51 (December 23, 2016). Available at: http://www.paho.org/hq/index.php?option=com_docman&task=doc_download&Itemid=270&gid=37567&lang=en, accessed on March 27, 2018. 9World Health Organization. Chikungunya. Available at: http://www.who.int/denguecontrol/arbo-viral/other_arboviral_chikungunya/en/, accessed on March 27, 2018. 10World Health Organization.WHO investigates outbreak of chikungunya in Balochistan province, Pakistan. Available at:http://www.emro.who.int/pandemic-epidemic-diseases/outbreaks/who-investigates-outbreak-of-chikungunya-in-balochistan-province-pakistan.html, accessed on March 27, 2018. 11World Health Organization. Chikungunya - France. Available at: http://www.who.int/csr/don/23-october-2014-chikungunya/en/, accessed on March 27, 2018. 12World Health Organization. Chikungunya - France. Available at: http://www.who.int/csr/don/25-august-2017-chikungunya-france/en/, accessed on March 27, 2018. 13World Health Organization. Chikungunya – Italy. Available at: http://www.who.int/csr/don/29-september-2017-chikungunya-italy/en/, accessed on March 27, 2018. COMMUNICABLE DISEASES WATCH 23 Mar 11 - Mar 24 2018 WEEKS 11 - 12 VOL 15 ISSUE NO 6

Management of scabies outbreak in institutional settings Reported by Dr Ambrose WONG, Senior Medical and Health Officer, Field Epidemiology Training Programme, and Ms Chloe POON, Scientific Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP.

Scabies is a skin infestation caused by a mite called Sarcoptes scabiei, which is a parasite that burrows into, resides and reproduces in human skin. It can affect people of all ages, but people with weakened immunity or the elderly are more likely to have heavy infestation. Scabies can spread rapidly in crowded conditions, hence, outbreaks of scabies have been reported in hospitals, child-care facilities, hostels and elderly homes. Diagnosis of scabies usually is made clinically based upon the appearance and distribution of the rash and the presence of burrows. The diagnosis of scabies could be confirmed by obtaining a skin scraping to examine under a microscope for the presence of mite or mite eggs. Effective treatment for scabies includes topical or oral anti-scabies agents and topical and/or oral drugs to control itchiness.

The Centre for Health Protection (CHP) of the Department of Health encourages institutions to report suspected outbreak of scabies to CHP for investigation and recommendation of appropriate control measures. Upon notification of a suspected scabies outbreak, CHP will carry out investigation which aims to confirm the occurrence of an outbreak, identify the affected and exposed persons, and implement measures for prevention and control.

An outbreak of scabies is defined as two or more cases which are considered to be epidemiologically linked in time and place by CHP.

From January 2017 to February 2018, CHP recorded 58 reports of scabies outbreaks in institutions, affecting a total of 194 persons. The monthly number of reported outbreaks ranged from zero to nine (median: four) (Figure 1). The majority (56, 96.6%) of the outbreaks occurred in residential care homes for the elderly and the remaining two outbreaks occurred in residential care homes for the disabled. Most of the scabies outbreaks (91.4%) were reported by the affected institutions and the remaining were reported by healthcare professionals providing care for the affected persons. Forty outbreaks (69.0%) had laboratory confirmation by microcopy of tissue scraping collected from the affected persons. The number of persons affected in each outbreak ranged from two to 18 with a median of three persons. The male-to-female ratio of the affected persons was 1 to 2. Among the affected persons, 98.5% involved residents while the remaining 1.5% involved staffs working in the Figure 1 - Monthly number of institutional outbreaks of scabies institutions. reported to CHP, 2017–2018 (as of February 2018).

Upon notification of a suspected outbreak, CHP will collect epidemiological information regarding demographics and clinical history of the affected persons, number of persons exposed including both the staff and residents of the concerned institution and potential risk factors (e.g. sharing of personal items) which may contribute to the outbreak, for formulation of appropriate control and prevention actions.

Staff and residents of the concerned institution should maintain good personal and environmental hygiene including having a bath every day, changing of clean clothes every day, and avoid sharing of clothing and personal items with others. Clothing and bed-linen of the affected person should be washed separately from those of other residents and must be washed in hot water (60°C or above for not less than 10 minutes) to get rid of the mites and their eggs. Non-washable personal items such as shoes should be placed in a plastic bag and seal up for at least 14 days before they can be used and cleaned as usual.

Topical use of 5%permethr in is effect ive medic atio n t o k ill the mites. During institut ional ou tb reak , it can be of fer ed to all exposed persons including both staff and residents as preemptive treatment . Clear instructions will be given to the affected institutions on how to apply the medication correctly which include: ❖ After taking a bath, scrub and dry the body thoroughly; ❖ With the help of another person, use latex gloves to thoroughly massage the lotion onto the skin of the whole body down to the soles, then put back the same clothes; and ❖ Leave for eight to 14 hours, take a warm water bath to wash away the medication, then put on clean clothes and change bed linen.

To prevent scabies infestation, members of the public and residents/ staff of institutions could adopt the following measures: ✦ Keep good personal hygiene, perform hand hygiene frequently and daily bathing; ✦ Regularly change into clean clothing, towels and bed linen; ✦ Avoid sharing clothing and personal items with others; and ✦ Perform skin inspection for institutionalised residents regularly for early identification of infestation.

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NEWS IN BRIEF A sporadic case of psittacosis On February 23, 2018, the Centre for Health Protection (CHP) recorded one sporadic case of psittacosis affecting a 68- year-old male with underlying illnesses. He had presented with fever, cough with sputum and shortness of breath since March 3 and was admitted to a public hospital on March 7. The clinical diagnosis was pneumonia. He was treated with antibiotics. He remained stable and was discharged home on March 26. His nasopharyngeal aspirate (NPA) collected on March 7 was tested positive for Chlamydophila psittaci DNA by PCR. He had no travel history and did not report any contact history of birds or their excreta during the incubation period. His home contacts were asymptomatic.

Workshop on Application of Molecular Diagnostics on Clinical Microbiology on March 20 and 21, 2018 A one-and-a-half day “Workshop on Application of Molecular Diagnostics on Clinical Microbiology” was conducted on March 20 and 21, 2018, which consisted of didactic lectures from overseas industry forerunners and local academics as well as round-table discussions on the way forward for Hong Kong. The workshop started with the sharing of novel and emerging technologies in molecular microbiology diagnostic principles and practice. The applications in areas such as point of care testing for HIV and Hepatitis, utilisation of genome sequencing in TB outbreak investigation and future development bioinformatics in the area of geo-positioning to facilitate country- wide or even global disease control were discussed. There were fruitful experiences sharing and exchange by overseas and local experts in particular on the practical utilisation of different methods in genome sequencing and ways to focus on base-pairs of concern in order to reduce the processing Photo of the speakers and moderators taken at the time. Audiences were enlightened on the importance of the further Opening Ceremony of the Workshop. developments in the field. All the information has been uploaded onto the HONG KONG Training Portal on Infection Control and Infectious Diseases (http://icidportal.ha.org.hk/sites/en/Lists/Training%20Calendar/DispForm.aspx?ID=130&Source=http%3A%2F%2Ficidportal%2Eha%2Eorg%2Ehk%2Fsites%2Fen% 2FLists%2FTraining%2520Calendar%2Fcalendar%2Easpx%3FCalendarDate%3D10%252F3%252F2018).

CA-MRSA cases in February 2018 In February 2018, CHP recorded a total of 101 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 61 males and 40 females with ages ranging from eight months to 81 years (median: 40 years). Among them, there were 69 Chinese, 6 Filipinos, 5 Pakistani, 2 Caucasian, 2 Indonesian, 1 Indian, 1 Japanese, 1 Korean, 1 Malaysian, 1 Sri Lankan and 12 of unknown ethnicity.

Ninety-nine cases presented with uncomplicated skin and soft tissue infections while the remaining two cases had severe CA-MRSA infections. The first severe case affected an eight-year-old girl with good past health. She had left ankle sprain in late January and developed pain, swelling and redness over left shin since February 6. She was admitted to a public hospital on February 10. X-ray of her left ankle revealed left ankle fracture. She was treated with antibiotics, incision and drainage of deep abscess, partial ostectomy of left tibia and excisional debridement of necrotic bone tissue. Pus from the deep abscess and necrotic bone tissue of her left leg collected on February 12 and February 14 respectively were both cultured positive for CA- MRSA. Her diagnosis was left tibia osteomyelitis. She remained in a stable condition and was discharged on March 9.

The second severe case affected a ten-year-old boy with good past health. He presented with fever, productive cough and abdominal pain since February 15. He was admitted to a private hospital on February 18 for further management. His chest X-ray taken on the day of admission showed pneumonic changes. His sputum collected on the same day was cultured positive for CA-MRSA. He was diagnosed with CA-MRSA associated pneumonia and was treated with antibiotics. He remained in a stable condition and was discharged on March 2.

Among the 101 cases, three cases involved healthcare workers were recorded, including two nurses and a prosthetist- orthotist working in different hospitals. Investigation did not reveal any cases epidemiologically linked to these three patients. Besides, two household clusters, with each affecting two persons, were identified.

Scarlet fever update (February 1, 2018 – February 28, 2018) Scarlet fever activity in February decreased as compared with that in January. CHP recorded 179 cases of scarlet fever in February as compared with 409 cases in January. The cases recorded in February included 100 males and 79 females aged between 13 months and 53 years (median: six years). Among them, there were two cases requiring admission to intensive care unit. The first case affected a 15-year-old girl with good past health. She presented with fever, productive cough, sore throat, vomiting, diarrhoea and rash on January 22, and was admitted to a public hospital on January 30. She was diagnosed to have scarlet fever and influenza B co-infection. She was complicated with pneumonia and toxic shock syndrome. She was treated with antibiotics and Tamiflu. She recovered and was discharged on February 7. The second case affected an eight-year-old boy with underlying medical disease. He had presented with fever, sore throat, rash over body and painful erythematous swellings over left lower limb since January 23 and was admitted to a public hospital on January 25. He was diagnosed to have left lower limb , surgical scarlet fever and septic shock. He was treated with antibiotics and discharged on February 28. No fatal cases were reported in February. There were seven institutional clusters occurring in four kindergartens/child care centres, two primary schools and a special school, affecting a total of 15 children.

COMMUNICABLE DISEASES WATCH 25 Mar 25 - Apr 7 2018 WEEKS 13 - 14 VOL 15 ISSUE NO 7

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrY onnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / Simon Wong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C, Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS

The Wholesale Supply Data of Antibiotics to Various Sectors in 2014-2016 Reported by Mr LAU Ka-wing, Senior Pharmacist and Dr Ken NG, Consultant (AMR), Infection Control Branch, CHP.

Introduction The Government of the Hong Kong Special Administrative Table 1 - Classification of antibiotics under “Antibacterials for Systemic Use” (J01) of ATC classification system used by WHO. Region attaches great importance to the threat of antimicrobial resistance (AMR) and has launched the Hong Kong Strategy Code Classes of Antibiotics and Action Plan on Antimicrobial Resistance (2017-2022) (Action Plan) in 2017 to combat the problem. The Action Plan set J01A Tetracyclines out monitoring of antibiotics usage as one of the strategic actions. J01B Amphenicols As currently there is no mechanism to obtain territory-wide antibiotics usage data, wholesale supply data of antibiotics may J01C Beta-lactam antibacterials, penicillins serve as a proxy to reflect the usage. Hence, the Department J01D Other beta-lactam antibacterials of Health (DH) conducted an exercise in 2017 to collect the annual wholesale supply quantities of all the registered J01E Sulfonamides and trimethoprim antibiotics classified under the World Health Organization (WHO) Anatomical Therapeutic Chemical (ATC) classification J01F Macrolides, lincosamines and streptogramins code J01 (Table 1), the Antibacterials for Systemic Use, through J01G Aminoglycoside antibacterials licensed drug wholesalers. J01M Quinolone antibacterials Methodology and Analysis J01R Combinations of antibacterials* DH collected wholesale supply data from 2014 to 2016 through standardised questionnaire from licensed wholesalers who J01X Other antibacterials distributed antibiotics. The licensed wholesalers were *There was no registered product under “Combinations of requested to provide wholesale data of relevant antibiotics to Antibacterials” (J01R) in Hong Kong. eight sectors including DH, Hospital Authority (HA), private hospitals, private doctors (mutually exclusive with private hospitals), dentists, veterinary surgeons, community pharmacies and farmers. Only oral and parenteral preparations were included.

Results were analysed and presented as defined daily dose (DDD), a standardised unit adopted by WHO to facilitate comparison. It is defined as “the assumed average maintenance dose per day for a drug used for its main indication in adults”. Annual DDD per 1 000 inhabitants per day (DID) was calculated to estimate drug use adjusted for population. DID is commonly adopted by overseas health authorities to reflect the national consumption trend. Figure 1 - Total amount of antibiotics supplied by wholesalers for human use in Hong Kong (2014-2016). Key Findings Overall local wholesale supply of antibiotics for human use in 2014, 2015 and 2016 were 22.24, 22.63 and 23.74 DID respectively, with an increase of 1.8% (0.39 DID) from 2014 to 2015 and 4.9% (1.11 DID) from 2015 to 2016 (Figure 1).

COMMUNICABLE DISEASES WATCH 26 Mar 25 - Apr 7 2018 WEEKS 13 - 14 VOL 15 ISSUE NO 7 Results by Antibiotics Class The top three classes of antibiotics with the highest volume of wholesale supply in 2014-2016 were: “beta-lactam penicillins”; “macrolides, lincosamines and streptogramins” and “other beta-lactam antibacterials” (Figure 2).

They accounted for 76 to 77% of overall local antibiotics supply to human in 2014-2016.

Results by Sectors The top three sectors supplied with the largest Figure 2 - Proportion of different classes of antibiotics supplied (2014-2016). proportion of overall antibiotics in 2014-2016 were (Remarks: There was no registered product under “Combinations of Antibacterials” (J01R) in Hong Kong. Antibiotics supplied to farmers and veterinary surgeons were included.) private doctors (51.4-51.9%), HA (20.8-21.4%) and community pharmacies (18.2-18.6%) (Figure 3).

Results by Broad Spectrum Antibiotics Broad spectrum antibiotics are usually reserved for treating infection caused by resistant bacteria and some are even recognised as last resort antibiotics, such as carbapenems and colistin.

Eleven locally important broad spectrum antibiotics only accounted for 0.94 to 1.11% of the total supply in Hong Kong in 2014-2016, majority of them (99.2-99.4%) were supplied to Figure 3 - Wholesale supply of antibiotics by sectors. (Remarks: This survey cannot reflect the appropriateness of antibiotic use by different sectors as there is no information on the case mix hospitals (Table 2). and load they have encountered.)

The top three were piperacillin with tazobactam, meropenem and Table 2 - Examples of broad spectrum antibiotics. Some locally-important broad spectrum vancomycin. They only accounted for less than 1% (0.76-0.92%) of the ATC Group total supply and the rest accounted for less than 0.2% (Figure 4). antibiotics Beta-lactam Their yearly DID change was -1.2%-18.3% (2014 to 2015) and 7.9%- Piperacillin with tazobactam antibacterials, 26.0% (2015 to 2016). penicillins (J01C) Cefepime The detailed report of the results can be found at the Centre for Health Protection website as follows: https://www.chp.gov.hk/en/static/100290.html. Cefoperazone with sulbactam Other beta-lactam Ceftazidime antibacterials (J01D) Discussion Imipenem with cilastatin

The top three classes of antibiotics with the highest volume of Meropenem wholesale supply were antibiotic groups that are being used to treat common bacterial infections in both community and hospital Colistin settings. They are usually prescribed as first-line treatment for Daptomycin suspected bacterial infections. Other antibacterials Linezolid (J01X) The locally important broad spectrum antibiotics only accounted for Teicoplanin a very small proportion of the total local supply. The majority of Vancomycin them were supplied to HA and private hospitals. This distribution is expected as these sectors provide secondary and tertiary care, in which more vulnerable patients with resistant infections are being taken care of.

Private doctors, HA and community pharmacies were the three sectors supplied with the highest volume of antibiotics. As private doctors and HA are the major healthcare provider in community and hospital settings, this result is not unexpected. Close monitoring is required as about 18% of total antibiotics were supplied to community pharmacies.

In view of the survey result, DH has launched a series of health promotion and education campaigns to advocate appropriate use of Figure 4 - Wholesale supply of selected broad spectrum antibiotics. antibiotics; together with other experts and stakeholders, DH had

COMMUNICABLE DISEASES WATCH 27 Mar 25 - Apr 7 2018 WEEKS 13 - 14 VOL 15 ISSUE NO 7 updated the Interhospital Multi-disciplinary Programme on Antimicrobial ChemoTherapy (IMPACT) guidelines and launched the Antibiotic Stewardship Programme in Primary Care to promote prudent use of antibiotics in both hospitals and community settings. DH has also stepped up enforcement actions against illegal sales of antibiotics (Table 3). Table 3 - Advice to public, community pharmacies and healthcare workers on antibiotic use. Advice to public ✦ Do not purchase antibiotics without a prescription; ✦ Do not demand antibiotics from your doctor; ✦ Follow your doctor’s advice when taking antibiotics; and ✦ To prevent AMR, maintaining personal hygiene and receiving up-to-date vaccination are equally important. Advice to community pharmacies

✦ Only supply antibiotics in accordance with the law; ✦ Illegal sale of antibiotics is a criminal offence; and - For example, supply of prescription antibiotics to the general public without the authorisation of a prescription ✦ The maximum penalty is a fine of $30 000 and 12 months of imprisonment.

Advice to healthcare workers

✦ Antibiotics are precious resources against infections. Healthcare workers play an essential role in preserving them: • Continue to prescribe antibiotics in accordance with therapeutic guidelines in consideration of clinical situations; • Discuss with your patients about the importance of appropriate antibiotic use and the dangers of AMR; • Apply best practice of infection prevention and control; • Talk to your patients about how to prevent infections and their spread; and - For example, vaccination, maintain personal hygiene and hand hygiene.

Wholesale supply data of antibiotics can only provide part of the information of overall situation of antibiotic use. DH will, in joint effort with other government departments and organisations, initiate other surveillance activities to provide a more comprehensive picture on the overall antimicrobial resistance (AMR) situation in Hong Kong.

Limitations This exercise was based on wholesale supply data, which has not taken into account factors such as natural wastage, disposal of expired products and procurement of non-registered drugs through name-patient basis. Wholesale supply data are neither representative of consumption data nor dispensing data; and contain no information to reflect appropriateness of antibiotic use.

Review of HIV/AIDS epidemiology in 2017 Reported by Dr Michelle MY CHAK, Medical and Health Officer, Dr Billy CH HO, Senior Medical and Health Officer, and Dr Kenny CW CHAN, Consultant, Special Preventive Programme, Public Health Services Branch, CHP.

The Department of Health (DH) implemented a voluntary anonymous case-based HIV and AIDS reporting system with input from both clinicians and laboratories in 1984 following the first report of HIV. The cumulative number of HIV and AIDS reports in Hong Kong reached 9 091 and 1 857 cases at the end of 2017.

The annual number has decreased slightly for the past two years after a record high of 725 cases in 2015. The number of HIV reports decreased by about 1.6% to 681 in 2017 as compared with that of 692 in 2016 (Figure 1).

Similar to previous few years, the HIV situation in Hong Kong in 2017 was still dominated by sexual transmission, which accounted for 79.1% of all reported cases. Men who have sex with men (MSM), which includes homosexual and bisexual contact, was the commonest mode of transmission and accounted for more than half (62.8%) of all HIV reports. In fact, MSM has accounted for a continually expanding proportion among infected male cases, from 58.7% in 2011 to 72.1% in 2017. The number of HIV reports from MSM has been persistently higher than that from heterosexual men since Figure 1 - HIV and AIDS reports (2008 to 2017). 2005, and the trend continued to widen in the past few years (Figure 2).

COMMUNICABLE DISEASES WATCH 28 Mar 25 - Apr 7 2018 WEEKS 13 - 14 VOL 15 ISSUE NO 7 The majority of the HIV reports in 2017 were male (86.9%), Chinese (73.3%) and diagnosed at the age between 20 and 49 (85.0%). The male-to-female ratio was 6.7 in 2017, which had been on an increasing trend in the past five years, a reflection of the increasing contribution of MSM cases in the past few years.

There were 111 cases of heterosexual transmission in 2017, which accounted for 16.3% of newly reported cases and which has remained stable in recent five years. Among them, 56 were male and 55 were female. The male-to-female ratio ranged from 0.9 to 1.23 in the past few years. Chinese ethnicity accounted for 73.2% of heterosexual male cases and 43.6% of heterosexual female Figure 2 - Route of transmission, excluding unknown route (1984 to 2017). cases. The median ages were 46 and 42 respectively, which were older than their MSM counterpart of 32. Cases aged 50 to 59 and 30 to 39 were most commonly reported in heterosexual male and female cases respectively.

In 2017, over half (58.3%) of the reported HIV cases were assessed to have contracted the virus locally, 11.6% in Mainland China and 7.6% in other places respectively. 22.5% had unknown place of infection due to inadequate information. When comparing heterosexual men and MSM, a higher proportion of MSM were infected locally (76.8%) than heterosexual men (53.6%). In contrast, more heterosexual male cases (39.3%) and heterosexual female cases (38.2%) were infected in Mainland China and other places as compared to only 18.0% among MSM. This suggested that non-local infections had an impact on the HIV transmission among heterosexual population.

In 2017, the three commonest sources of HIV notification were public hospitals/ clinics (38.9%), DH’s Social Hygiene Clinic (16.2%) and DH’s AIDS unit (15.6%). The proportion of HIV cases reported from AIDS service organisations (i.e. non-governmental organisations, NGOs) decreased from 16.3% (113 cases) in 2016 to 13.5% (92 cases) in 2017. On the contrary, notifications from DH AIDS Unit increased from 9% (62 cases) in 2016 to 15.6% (106 cases) in 2017.

Since the introduction of highly active antiretroviral therapy (HAART) in Hong Kong in around 1997, the annual number of reported AIDS cases has stabilised and remained at a level of around 90 to 100 cases per year in the past decade. A total of 91 AIDS cases were reported in 2017 as compared with 111 cases in 2016, which brought the cumulative total to 1 857 AIDS cases. The two most common AIDS defining illnesses in Hong Kong continued to be Pneumocystis pneumonia and tuberculosis, and accounted for 67.0% of all new AIDS reports in 2017.

Overall, the number of newly reported HIV infections in Hong Kong stayed at a high level in the past few years and was still in an overall increasing trend. The high number was still dominated by MSM transmission, of which, young MSM infected cases in the recent years remained a major concern. The HIV situation of heterosexual population and injecting drug user was relatively stable in the past decade.

Close monitoring of the HIV situation, sustaining high quality clinical services and close collaboration with community organisations are crucial for the control of HIV epidemic in Hong Kong in the future.

Get early testing for HIV Early diagnosis of HIV infection could facilitate access to and uptake of treatment and care, including HAART. Treatment is highly effective. In addition to reducing morbidity and mortality, it further prevents onward transmission to sexual partners. Anyone with the risk behaviour or interested in knowing his HIV status should get tested for HIV early, either by attending any HIV testing service or by performing HIV self-testing with a reliable, good-quality test kit.

MSM, in particular, should test for HIV at least once per year irrespective of their sexual practice. They are also advised to repeat the HIV test after the window period, which is generally three months since the last time they were at risk.

People can call DH’s AIDS Hotline (2780 2211), Gay Men HIV Testing Hotline (2117 1069) or contact various AIDS NGOs for free and anonymous HIV testing and counselling services. They may also attend Social Hygiene Clinics (free for eligible person), or consult their family doctors for HIV testing.

By providing an opportunity for people to test themselves discreetly and conveniently, HIV self-testing could be an efficient avenue to reach those who are not currently reached by existing HIV voluntary counselling and testing (VCT) services. Self-testing refers to the process by which a person who wants to know his or her HIV status collects a specimen, performs a test and interprets the test result in private. It does not provide a definitive diagnosis. Any positive HIV result must be confirmed by laboratory-based testing with a venous blood sample. More information on HIV testing can be found on www.27802211.com and www.21171069.com.

COMMUNICABLE DISEASES WATCH 29 Mar 25 - Apr 7 2018 WEEKS 13 - 14 VOL 15 ISSUE NO 7

NEWS IN BRIEF

Two domestic clusters of pertussis

From March 27 to April 3, 2018, the Centre for Health Protection (CHP) recorded two domestic clusters of pertussis. The first cluster involved a three-month-old baby girl and her 31-year-old mother. The baby girl, who had good past health, presented with cough, runny nose with reduced appetite on March 10. She was admitted to a public hospital on March 24 and her nasopharyngeal swab collected on March 25 was tested positive for Bordetella pertussis. Her condition was stable and she was discharged on March 26. She was given a course of antibiotics upon follow-up on March 28.

Contact tracing revealed that the baby’s mother had cough on March 18 and her pernasal swab collected on March 28 by CHP was tested positive for Bordetella pertussis. The baby’s father also had cough since early March and his pernasal swab collected on March 28 by CHP was tested negative for Bordetella pertussis. They were given a course of antibiotics and did not require hospital admission. Their condition was stable. The girl had received the first dose of Diphtheria, Tetanus, acellular Pertussis and Inactivated Poliovirus (DTaP-IPV) vaccine while her mother had received four doses of pertussis-containing vaccine.

The second cluster involved a two-month-old girl, her 32-year-old father and 33-year-old mother. The girl, with good past health, presented with cough, vomiting and cyanotic spells on March 14. She was admitted to a public hospital on March 23 and her nasopharyngeal aspirate collected on the same day was tested positive for Bordetella pertussis. She was treated with antibiotics and her condition was stable. She was discharged on April 3.

Upon contact tracing, her mother and father were found to have cough on March 17 and March 25 respectively. They were referred to a public hospital by CHP and their nasopharyngeal aspirates collected on March 27 were tested positive for Bordetella pertussis. They were treated with antibiotics and did not require hospitalisation. Their condition was stable. The girl had received the first dose of DTaP-IPV vaccine and vaccination history of her parents was unsure.

Epidemiological investigation revealed that the five patients had no travel history during the incubation period. Investigations are ongoing.

A sporadic case of necrotising fasciitis due to infection On April 3, 2018, CHP recorded a sporadic case of necrotising fasciitis due to Vibrio vulnificus infection affecting a 53-year-old man with pre-existing medical conditions. He presented with fever, left forearm redness and painful swelling preceded by fish stint on April 1. He was admitted to a public hospital on the same day. The diagnosis was necrotising fasciitis. He was treated with antibiotics and surgical debridement. Necrotic tissue collected was tested positive for Vibrio vulnificus. His current condition was stable. The patient was reported to have fish sting injury while preparing it for meal before symptom onset. He did not travel during the incubation period.

A sporadic case of psittacosis

On April 4, 2018, CHP recorded a sporadic case of psittacosis affecting a 67-year-old woman with good past health. She presented with fever, cough with blood-stained sputum since March 22 and was admitted to a public hospital on March 26. Her chest X-ray showed right lower zone consolidation and the diagnosis was pneumonia. Her sputum collected on March 26 was tested positive for Chlamydophila psittaci DNA by polymerase chain reaction (PCR). She was treated with antibiotics. She remained stable all along and was discharged on March 29. The patient had no travel history and did not report any contact with birds during the incubation period. Her home contacts remained asymptomatic.

COMMUNICABLE DISEASES WATCH 30 Apr 8 - Apr 21 2018 WEEKS 15 - 16 VOL 15 ISSUE NO 8

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Summary of the 2017/18 winter influenza season in Hong Kong Reported by Ms Vera CHOW, Scientific Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP.

The 2017/18 winter influenza season in Hong Kong started in the second week of 2018 and ended in late March, which lasted for about 12 weeks.The duration was shorter than the major seasons in the past three years (about 16 weeks in the 2014/15 and 2015/16 winter seasons, and 2017 summer season).

Laboratory surveillance The weekly positive percentage for influenza among respiratory specimens received by the Public Health Laboratory Services Branch of the Centre for Health Protection (CHP) of the Department of Health started to increase in late December 2017 and rapidly rose to exceed baseline threshold of 10.7% in the first week of 2018 (Figure 1). It reached the peak of 27.21% in week ending February 17 and then decreased steadily to 9.38% and 6.14% (below the baseline threshold of 10.7%) in the last two weeks of March. In this season, the peak percentage was lower than that recorded in the summer season last year Figure 1 - Percentage of respiratory specimens tested positive for influenza viruses, 2014-2018. (Note: The baseline threshold is 1.96 standard deviation above the average weekly positive percentage during (about 41%). non-season periods from 2014-2017.)

About 76% of the positive influenza detections were influenza B (Figure 2), and among the influenza B detections, about 95% belonged to the Yamagata lineage which was included in the quadrivalent seasonal influenza vaccine (SIV) for the 2017/18 Northern Hemisphere season but not the trivalent SIV. The percentage of respiratory specimens tested positive for influenza A(H1N1)pdm09 and influenza A(H3N2) viruses remained at a low level throughout this season. Figure 2 - Percentage of respiratory specimens tested positive for influenza viruses by subtype, 2014-2018.

COMMUNICABLE DISEASES WATCH 31 Apr 8 - Apr 21 2018 WEEKS 15 - 16 VOL 15 ISSUE NO 8 Influenza-like illness (ILI) outbreaks in schools/ institutions Regarding ILI outbreaks in schools and institutions reported to CHP, the number markedly increased to a very high level between late January and early February, with 105 to 115 outbreaks recorded per week from January 21 to February 10 (Figure 3). A total of 600 ILI outbreaks were recorded in this season, which was the highest number recorded during influenza seasons since 2013 (the previous high was 437 outbreaks recorded in the 2015/16 winter season). Figure 3 - Weekly number of ILI outbreaks in schools and institutions, 2014-2018.

Before the Chinese New Year holiday, Table 1 - Number s and percentages of ILI outbreaks in sc hools and institutions dur ing 2017/18 winter season. about 80% of the ILI outbreaks January 7 - February 10 (5 weeks) February 11 - March 31 (7 weeks) Type of institutions occurred in kindergartens/child care (Before Chinese New Year holiday) (After Chinese New Year holiday) centres (KG/CCC) and primary KG/CCC 172 (39.3%) 55 (34.0%) schools (PS) (40.4% and 39.3% in PS PS 177 (40.4%) 33 (20.4%) and KG/CCC respectively), whereas Secondary school 36 (8.2%) 10 (6.2%) only 5.0% took place in residential RCHE 22 (5.0%) 50 (30.9%)

care homes for the elderly (RCHE) Residential care home for persons 9 (2.1%) 6 (3.7%) (Table 1). After the holiday, there was with disabilities significant decrease in the number of Others 22 (5.0%) 8 (4.9%) outbreaks in KG/CCC and PS. Total 438 162

Influenza-associated hospitalisation in public hospitals The overall admission rate with principal discharge diagnosis of influenza in public hospitals among all ages increased steadily since mid-December last year, and reached the peak of 1.52 cases per 10 000 population in the week ending February 17 (Figure 4). It gradually decreased to 0.19 in the last week of March, which was below the baseline threshold of 0.20.

Table 2 shows the peak weekly admission rates by age groups recorded in major influenza seasons Figure 4 - Weekly influenza-associated hospital admission rate in public hospitals, 2014-2018. (Note:The baseline threshold is 1.96 standard deviation above the average weekly admission rate during non-season from 2015 to 2018. The peak weekly periods from 2014-2017.) rate among all ages (1.52) exceeded that for the 2014/15 and 2015/16 winter season (1.17 and 0.67 Table 2 - Peak weekly admission rates (per 10 000 population) recorded dur ing major influenza seasons, 2015-2018. respectively) but was lower than that for the summer season last year Peak weekly admission rate (per 10 000 population) Season (1.91). In the current season, the peak 0-5 6-11 12-17 18-49 50-64 ≥65 All ages weekly rate was highest among young children aged five years or less 2017/18 winter# 8.63 3.81 1.48 0.35 0.87 4.26 1.52 (8.63), followed by elderly aged 65 years or above (4.26) and then 2017 summer* 9.07 1.63 0.61 0.31 0.88 6.40 1.91 children aged six to 11 years (3.81). When comparing with previous 2015/16 winter^ 6.15 1.79 0.38 0.17 0.38 1.04 0.67 seasons, the peak rates among children aged six to 11 years and 12 2014/15 winter* 2.78 1.26 0.42 0.16 0.39 5.34 1.17 to 17 years in this season greatly exceeded the respective highest #Predominated by influenza B levels recorded in previous seasons *Predominated by influenza A(H3N2) ^ by more than one-fold. Predominated by influenza A(H1N1)pdm09 and influenza B COMMUNICABLE DISEASES WATCH 32 Apr 8 - Apr 21 2018 WEEKS 15 - 16 VOL 15 ISSUE NO 8 Severe influenza cases CHP has collaborated with the Hospital Authority and private hospitals to monitor intensive care unit (ICU) admissions and deaths with laboratory confirmation of influenza among adult patients. For surveillance purpose, the cases refer to laboratory-confirmed influenza patients who require ICU admission or die within the same admission of influenza infection. It should be noted that their causes of ICU admission or death may be due to other acute medical conditions or underlying diseases.

During this season, a total of 570 cases (including 382 deaths) of ICU admission or death with laboratory confirmation of influenza were recorded among adult patients aged 18 years or above, as compared with 647 (501 deaths), 409 (211 deaths) and 582 (430 deaths) recorded in the 2014/15 winter, 2015/16 winter and 2017 summer seasons respectively.

The male-to-female ratio was 1:0.87. Their ages Table 3 - Age distr ibution of severe/fatal cases recorded in 2017/18 winter influenza season and ranged from 25 to 104 years (median: 78 years). their vaccination history. Number of severe cases known About 75% had pre-existing chronic medical Number of severe cases Age group Number of deaths (%) to have received 2017/18 SIV (including deaths) (%) diseases. Among the elders aged 65 years or above (coverage %) who lived in RCHE and in the community, 58.6% and 27.2% were known to have received SIV for 0-5 13 (2.2%) 2 (0.5%) 0 (0%) the 2017/18 season respectively. Among the cases 6-11 aged 18 to 64 years, only seven (4.5%) were 5 (0.8%) 0 (0%) 0 (0%) known to have received SIV for the 2017/18 12-17 2 (0.3%) 0 (0%) 1 (50.0%) season (Table 3). 18-49 41 (6.9%) 8 (2.1%) 3 (7.3%) For paediatric cases of influenza-associated severe 50-64 116 (19.7%) 43 (11.2%) 4 (3.4%) complications and deaths, 20 cases (including two deaths) were recorded in this season, as compared Lived in RCHE: 65 (58.6%) with 18 (one death), 27 (three deaths) and 19 ≥65 413 (70.0%) 331 (86.2%) (three deaths) recorded in the 2014/15 winter, Lived in community: 82 (27.2%) 2015/16 winter and 2017 summer seasons Total 590 384 155 (26.3%) respectively. Two of them were imported cases from Mainland China. The cases involved 11 boys and nine girls.Their ages ranged from 19 months to Table 4 - Cumulative incidences of severe influenza cases (per 100 000 population) by age 15 years with a median of 4.5 years. Nineteen groups in major seasons from 2015 to 2018. patients (95%) did not receive any influenza vaccine 2014/15 winter 2015/16 winter 2017 summer 2017/18 winter Age group in this season. (16 weeks) (16 weeks) (17 weeks) (12 weeks)

0-5 2.9 4.1 4.1 3.2 In total, 590 severe cases (including 384 deaths) with laboratory confirmation of influenza were 6-11 1.6 2.1 0.6 1.4 recorded among all ages in this season. The majority of the severe cases affected elderly 12-17 0.6 1.5 0.6 0.6 persons (Table 3). The cumulative incidence of severe cases in this season was 8.0 cases per 18-49 0.6 1.7 0.9 1.2 100 000 population, which was within the historical range of 5.9 (2015/16 winter season) to 50-64 3.7 7.6 5.0 6.5 9.1 (2014/15 winter season) (Table 4). For all age ≥65 50.3 18.7 38.0 33.8 groups, the cumulative incidences recorded in this season were also within the ranges recorded in the All ages 9.1 5.9 8.1 8.0 previous seasons.

Among patients with laboratory confirmation of influenza admitted to public hospitals in this season, 2.5% of the admitted cases died during the same episode of admission. It was also within the historical range between 1.9% (2014/15 winter season) and 3.3% (2015 summer season).

In summary, the 2017/18 winter season was a season predominated by influenza B. Influenza B was rarely the single predominating virus in influenza seasons in Hong Kong in the past few years.The previous seasons with significant circulation of influenza B viruses occurred in the 2013/14 winter season and the 2015/16 winter season in which influenza B constituted 38.3% and 43.5% of the positive influenza detections.

Children were more affected in this season which was expected for an influenza B season. There were large number of institutional ILI outbreaks in KG/CCC and PS. Also, the influenza-associated hospitalisation rates among children were higher than previous seasons. However, the cumulative population incidences of severe cases among different age groups and the proportion of death among hospitalised influenza cases were within the range observed in previous seasons.

COMMUNICABLE DISEASES WATCH 33 Apr 8 - Apr 21 2018 WEEKS 15 - 16 VOL 15 ISSUE NO 8 Celebrating the World Immunization Week 2018 (April 24 to 30, 2018) Reported by Ms Fanny WS HO, Scientific Officer, Vaccine Preventable Disease Office, Surveillance and Epidemiology Branch, CHP. World Immunization Week (WIW), celebrated worldwide annually in the last week of April, is a global initiative led by the World Health Organization (WHO) to urge greater action on immunisation and promote the use of vaccines to protect people of all ages against diseases. This year, the WIW takes place in tandem with the Regional Immunization Week of the WHO Western Pacific Region, focusing on the theme “Protected Together, #VaccinesWork”, to highlight the importance of vaccination throughout life and encouraging people at every level to step up their efforts towards improving immunisation coverage for public good.

#VaccinesWork Vaccination has long been a safe and cost-effective strategy in the control and elimination of infectious diseases, predominantly those affecting infants and children. In the past two centuries, mass immunisation programmes worldwide have been remarkably successful in preventing millions of childhood deaths, eradicating smallpox globally and eliminating circulation of polio and measles from many countries. Regional success in controlling rubella through vaccination in the Americas and some parts of the Western Pacific region also makes this infection the next target for elimination worldwide.

As with many developed countries, the long-established childhood immunisation programme (CIP) in Hong Kong implemented since the 1950s has been effective in preventing many infectious diseases once common in the territory (Figure 1). For example, after global smallpox eradication in 1980, polio was eradicated locally in 2000, and Hong Kong was certified measles-free in 2016. Other vaccine-preventable diseases such as diphtheria, tetanus and rubella have been drastically reduced and maintained at record or near-record low levels in the past decade.

The current immunisation schedule provides children with immunisations for eleven infectious diseases, including tuberculosis, , diphtheria, tetanus, pertussis, poliomyelitis, measles, mumps, rubella, chickenpox and pneumococcal infection. Over the years, Hong Kong has sustained very high coverage levels with at least 95 percent of children getting the recommended immunisations, achieving sufficient herd protection to prevent the spread of these diseases in the community.

Protected Together Ye t , d e s p i t e s u c c e s s o f ro u t i n e i m mu n i s a t i o n , outbreaks may still occur in highly vaccinated populations where immunity gaps exist. One example is the recent resurgence of measles and pertussis in many places including the United States and Europe, as well as the ongoing measles outbreak in Japan and Taiwan which underscore the potential risk of infection among pockets of unvaccinated or under-vaccinated people. This could be in part due to the accumulation of susceptible individuals over time as immunity acquired through vaccination in childhood may wane with increasing age. Additionally, the apparent increase in vaccine hesitancy in these countries may also contribute to under-vaccination, leading to an increased risk of disease Figure 1 - Year of vaccine introduction into the CIP and notification rates of measles, rubella, pertussis, outbreaks. acute poliomyelitis, diphtheria and tetanus in Hong Kong, 1946-2017.

Likewise, with the increasing frequency of international travel and a rapidly expanding world population, there remains a continued risk of exposure to infectious diseases from countries where vaccine uptake is low or immunisation service is lacking. As such, travellers going to endemic areas should keep their vaccinations up-to-date and receive necessary immunisations before departure.

COMMUNICABLE DISEASES WATCH 34 Apr 8 - Apr 21 2018 WEEKS 15 - 16 VOL 15 ISSUE NO 8 As the epidemiology and risk of infectious diseases in other places may be different from Hong Kong, children staying or living other places should follow the vaccination schedule of their residing country. Catch-up vaccinations should be considered for any immigrants, overseas students or workers with uncertain or incomplete vaccination status, preferably prior to arrival. Further, whenever appropriate, consideration should also be given to any vaccinations that may be relevant to one’s underlying medical conditions, occupation or lifestyle for personal protection against diseases (e.g., human papillomavirus, meningococcal disease).

Vaccination is a collective responsibility and everyone has a role to play. For healthcare professionals, every encounter with a child represents an opportunity for vaccination and discussion with parents. The Primary Care Office of the Department of Health (DH) has developed a “Module on Immunisation” under the Hong Kong Reference Framework for Preventive Care for Children in Primary Care Settings to provide evidence-based references. Parents and caregivers also play an important role to ensure children get vaccinated according to the recommended schedule to protect them against vaccine-preventable diseases. Routine immunisations are instrumental to keep our children, families and communities healthy and free of vaccine-preventable diseases. DH, together with our partners, will continue to engage communities to improve vaccine acceptance and uptake, ultimately providing better protection to everyone, everywhere.

Additional information about WIW 2018 is available at the CHP website: https://www.chp.gov.hk/en/features/39340.html.

NEWS IN BRIEF

A sporadic case of necrotising fasciitis caused by Vibrio vulnificus On April 23, 2018, the Centre for Health Protection (CHP) recorded a case of necrotising fasciitis caused by Vibrio vulnificus affecting a 41-year-old male with underlying illnesses. He presented with fever, myalgia, diarrhoea and right lower limb painful swelling on April 16 and was admitted to a public hospital on April 19. Subsequently, he was found to have left lower limb bruising with skin mottling. His clinical diagnosis was necrotising fasciitis in both lower limbs. Above knee amputation for both limbs were performed on April 19 & 21 respectively. He was managed in the intensive care unit postoperatively and was treated with antibiotics. His right leg tissue and wound swab collected on April 19 grew Vibrio vulnificus. He was complicated with septic shock and multi-organ failure and died on April 22. The case was referred to the Coroner’s Court. According to the patient’s sister, he visited a wet market daily and had history of injury to his finger by raw shrimps at home on April 16 and did not know further details. He had no recent travel history and his home contacts were asymptomatic.

CA-MRSA cases in March 2018 In March 2018, CHP recorded a total of 92 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 56 males and 36 females with ages ranging from three months to 79 years (median: 40 years). Among them, there were 71 Chinese, 9 Filipinos, 3 Indian, 2 Nepalese, 1 Caucasian, 1 Pakistani, 1 Sri Lankan, 1 Thai and 3 of unknown ethnicity. Eighty-nine cases presented with uncomplicated skin and soft tissue infections while the remaining three cases had severe CA-MRSA infections. The first severe case affected a 69-year-old man with underlying medical diseases. He presented with fever and productive cough on February 18. He was admitted to a private hospital on February 19 for management. His chest X-ray taken on the day of admission showed pneumonic changes. His sputum was cultured positive for Streptococcus pneumoniae and CA-MRSA. He was diagnosed with pneumonia and was treated with antibiotics. He remained in a stable condition and was discharged on February 26. The second severe case affected a 66-year-old man with underlying medical conditions. He presented with fever and on March 2. He was admitted to a public hospital on the same day. His chest X-ray taken on the day of admission showed bilateral pneumonic changes. His blood specimen collected on March 3 was cultured positive for CA-MRSA. He was diagnosed to have sepsis and was treated with antibiotics. His condition deteriorated and was further complicated by other medical illnesses. He passed away on April 17. The third severe case affected a 65-year-old man with underlying illnesses. He was admitted to a public hospital on March 15 for management of pneumonia and heart disease. He was found to have wet over his right big toe. Wound swab collected from his right big toe on March 16, sputum collected on March 17 and blood collected on April 3 were all cultured positive for CA-MRSA. He was diagnosed to have right big toe gangrene, pneumonia and sepsis. Right below-knee amputation was performed on March 18. He subsequently developed acute kidney injury and metabolic acidosis requiring admission to ICU on April 3 to 5. He was treated with antibiotics and his condition was stable condition. Separately, the isolates of two cases were found to be resistant to mupirocin. The first case involved a 10-year-old girl who had back abscess in mid-February. She recovered after surgical drainage.The second case involved a 42-year-old woman who had right shoulder abscess in late February. She recovered after treatment with antibiotics and wound drainage. Both cases had history of uncomplicated CA-MRSA skin and soft tissue infection in 2017, while the CA-MRSA isolate from the first patient was also found to be resistant to mupirocin at the time. No epidemiological linkage was identified among the two cases. Among the cases, one was a nurse working in a public hospital. Investigation did not reveal any epidemiologically linked cases. Besides, five household clusters, with each affecting two persons, were identified.

Scarlet fever update (March 1, 2018 – March 31, 2018) Scarlet fever activity in March decreased as compared with that in February. CHP recorded 151 cases of scarlet fever in March as compared with 179 cases in February. The cases recorded in March included 98 males and 53 females aged between nine months and 27 years (median: five years).There were no fatal cases or institutional clusters reported in March.

COMMUNICABLE DISEASES WATCH 35 Apr 22 - May 5 2018 WEEKS 17 - 18 VOL 15 ISSUE NO 9

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Review of measles in Hong Kong (2013-2017) Reported by Ms Fanny WS HO, Scientific Officer, Vaccine Preventable Disease Office, Surveillance and Epidemiology Branch, CHP.

Background Measles was a common childhood infection prior to the introduction of measles vaccine. The disease is highly contagious, usually spread through airborne droplets or by direct contact with nasal or throat excretions of infected persons. Infants and immunosuppressed individuals are at a higher risk of complications, severe disease and death following infection, while measles during pregnancy may increase the risk of , stillbirth or preterm delivery.

Global situation Globally, measles elimination continues to be a public health priority. In 2016, an estimated seven million people were affected by measles despite an improved overall vaccine uptake worldwide1. Outbreaks were being reported not only in endemic regions, but also in countries with successful interruption of transmission or approaching elimination. In Europe, the number of reported measles cases had quadrupled from 5 273 cases in 2016 to 21 315 cases in 2017, with large-scale outbreaks occurring in Italy, Romania and Ukraine2. Measles is also an endemic infection in many areas in Asia. In the first two months of 2018, confirmed measles cases continued to be reported in the Philippines (855), Mainland China (689), Malaysia (453),Thailand (274) and Indonesia (254)3. Local outbreaks triggered by imported cases in places with low incidence have also occurred from time to time. For example, recently a traveller who acquired the infection in Thailand triggered outbreaks with spread to more than 100 persons in Okinawa and Aichi prefecture of Japan and a cluster of twelve cases in Taiwan4-6.

Local situation Hong Kong experienced a surge in measles infections from 2013 to 2014 after a period of low incidence in the four years prior to this surge (eight to 25 cases per year between 2009 and 2012). In 2013, 38 measles cases were recorded, and the number further rose to a high of 50 cases (0.69 cases per 100 000 population) in 2014 with six nosocomial and household clusters reported (Figure 1). This resurgence was gradually interrupted and the number of cases had decreased steadily to a low level by the end of 2015. Although there was an increase in the number of confirmed cases in Hong Kong during this upsurge, we managed to stop the ongoing transmissions from the cases. In September 2016, Hong Kong was certified by the World Health Organization as having eliminated measles, i.e. there was absence of endemic measles transmission (defined as existence of continuous transmission of indigenous or imported measles virus that persists for at least 12 months) for a period of at least 36 months. The annual totals had remained low since 2016, with nine, four and seven cases confirmed in 2016, 2017 Figure 1 - Number and notifications rate of reported measles cases in and 2018 (as of May 8) respectively. There have been no Hong Kong, 1990-2017. measles deaths since 1990.

Here we described the epidemiology of measles in Hong Kong in the past five years (2013-2017) and the characteristics of cases reported in this period. During the past five years, a total of 119 measles cases were reported, of which 54 were either imported (51 cases, 43%) or import-related (3 cases, 3%) (i.e. cases with a known epidemiological linkage to another confirmed imported case) (Table 1). Importations mainly occurred among foreign visitors to Hong Kong and local residents exposed to measles while travelling abroad (Table 2). For the remaining 65 cases, most of them were sporadic cases without known source of infection in Hong Kong after thorough epidemiological investigation.

COMMUNICABLE DISEASES WATCH 36 Apr 22 - May 5 2018 WEEKS 17 - 18 VOL 15 ISSUE NO 9 Table 1 - Measles cases by source of infectiona, 2013-2017 (N=119). Table 2 - Measles cases by place of impor tation, 2013-2017 (N=51). Unknown Year Total Endemic* Imported Import-related source# Number of imported cases Year Place of importation (% of total in a year) 2013 38 0 19 (50%) 19 (50%) 0

2014 50 0 23 (46%) 24 (48%) 3 (6%) Mainland China (13), Philippines (4) and 2013 19 (50%) 2015 18 0 14 (78%) 4 (22%) 0 Indonesia (2)

2016 9 0 8 (89%) 1 (11%) 0 Mainland China (14), Philippines (6), 2017 4 0 1 (25%) 3 (75%) 0 2014 24 (48%) India (1), Kenya (1),Taiwan (1) and United States (1) Total 119 0 65 51 3 Notes: 2015 4 (22%) Mainland China (3) and Indonesia (1) aCases are classified according to Guidelines on Verification of Measles and Rubella Elimination in the Western Pacific Region: http://www.wpro.who.int/ immunization/documents/measles_elimination_verification_guidelines_2013/en/. 2016 1 (11%) Indonesia (1) *Endemic cases refer to cases resulting from endemic transmission of measles virus (continuous transmission of indigenous or imported measles virus that persists for ≥12 months). #Unknown source cases refer to cases in which epidemiological or virological 2017 3 (75%) Australia (1), Indonesia (1) and Italy (1) linkage to importation or endemic transmission cannot be established.

Overall, their ages ranged from one month to 56 years with a median of 20 years. Ninety-five (80%) were Chinese, 11 (9%) were Filipino and the remaining 13 cases were of other ethnicities. Figure 2 and Table 3 show the vaccination history by age group and place of birth/residence respectively. Nearly one- third of the cases (36 cases, 30%) were infants less than one year of age who were not yet due for the first dose of Measles, Mumps and Rubella (MMR) vaccine according to the Hong Kong Childhood Immunisation Programme (HKCIP). Among these infant cases, 29 (81%) cases were born in Hong Kong including four who lived in Mainland China at the time of infection, while seven (19%) cases were born elsewhere. Of the 17 cases aged one to four years (14%), six cases had received the first dose of measles-containing vaccine (MCV), while 11 were unvaccinated including six children who were non-resident and hence not Figure 2 - Measles vaccination status by age group, 2013-2017. covered by the local immunisation schedule. Table 3 - Measles vaccination status by place of birth/residence (N=119). Age group Received ≥ 1 Unvaccinated or unknown Place of birth/residence Sixty cases (50%) were adults aged 18 or above, in which 23 (in years) dose of MCV vaccination history (38%) were local-born while the remaining 36 cases (60%) were Local born resident 0 29 born elsewhere including 17 born in Mainland China and nine in the Philippines. One adult case with travel history to the <1 (N=36) Non-local born resident 0 4 Philippines could not be contacted at the time of investigation, Non-resident 0 3 and therefore was excluded from analyses. Among the 36 Local born resident 6 6 foreign-born cases, 31 (86%) were migrants, foreign workers 1-4 (N=17) Non-local born resident 0 3 and overseas students who were all either unvaccinated or Non-resident 0 2 uncertain about their vaccination history. Seven of these cases were domestic helpers from the Philippines and Indonesia, of Local born resident 4 1 which three had travel history to their home country during the 5-17 (N=6) Non-local born resident 0 0 incubation period. Non-resident 0 1 Local born resident 3 20 There were seven small measles clusters (six involving two ≥18 (N=60)* Non-local born resident 0 31 cases and one involving five cases) reported over the review period, including six in 2014 and one in 2015 (Table 4). Five Non-resident 0 5 * were nosocomial clusters and two were household clusters. One case could not be contacted at the time of investigation, and Among the 15 cases affected in these clusters, 11 patients (73%) therefore is not included in the table. had never received measles vaccination. This was mainly because Table 4 - Measles clusters detected in Hong Kong, 2013-2017. the patients were either too young and not due for the first dose of MMR vaccine or they were not covered under the Year 2013 2014 2015 2016 2017 HKCIP. Four clusters had been associated with imported index Total number of cases 38 50 18 9 4 cases with travel history to Mainland China during the Number of clusters 0 6 (10)^ 1 (5) 0 0 incubation period, while the index cases of the remaining three (persons affected) clusters had not travelled outside Hong Kong. As for the five Size of cluster(s) - 2 in each^ 5 - - nosocomial clusters, immediate measures were taken to (i.e. number of cases) strengthen infection control and isolation practices. All clusters Hospital (4) were effectively contained without further spread. Setting - Home (2) Hospital - - ^Two of the measles cases were associated with more than one cluster. COMMUNICABLE DISEASES WATCH 37 Apr 22 - May 5 2018 WEEKS 17 - 18 VOL 15 ISSUE NO 9 Prevention and control measures Vaccination is the most effective measure to prevention measles infection. For years, measles has been successfully controlled in Hong Kong through a sustained high coverage of MMR vaccine of over 95% and well-performing surveillance systems. Besides, seroprevalence rates of measles virus antibodies in the local population have been maintained at a very high level (about 95% or above) among all age groups all along (https://www.chp.gov.hk/en/statistics/data/10/641/701/3536.html), indicating that the majority of the local population already had immunity against measles infection, either through past infection or vaccination.

Similar to other areas where endemic measles transmission has been eliminated, sustaining the elimination status of measles in Hong Kong remains a challenge, as sporadic cases and clusters will continue to appear from time to time until global eradication is achieved. As Hong Kong is an international city, importation of measles can occur at any time.This underscores the importance of timely vaccination for susceptible populations including young children, travellers, migrants and foreign domestic helpers who have not been fully vaccinated.

Travellers are advised to refer to the website of the Department of Health (DH)'s Travel Health Service for the latest outbreak news of the affected areas (https://www.travelhealth.gov.hk/english/travel_related_diseases/news.html#Measles). In addition, if travellers returning from affected areas develop symptoms of measles (e.g. fever and rash), they should seek medical advice immediately and avoid contact with non-immune persons, especially pregnant women and infants. They should also report their symptoms and travel history in advance to the healthcare workers so that appropriate infection control measures can be implemented at the healthcare facilities to prevent any potential spread.

As different places will develop different immunisation programmes in light of their epidemiological profiles, parents should arrange their children to receive vaccines according to the local immunisation programme of their usual place of residence. For instance, children aged under one who frequently travel to or stay in the Mainland should follow the Mainland's schedule of measles immunisation with the first dose of measles containing vaccine at eight months old, followed by another dose at 18 months.

Travellers to other regions where measles outbreaks are reported or endemic transmission occurs should keep their vaccinations up-to-date and receive necessary immunisations at least two weeks before departure. In view of the potential vaccination gaps among foreign domestic helpers, the Centre for Health Protection (CHP) of DH advises that employment agencies and employers should arrange MMR vaccination for foreign domestic helpers who had never been infected with measles or received measles vaccination during their pre-employment medical checkup or prior to arrival.

In view of the recent measles outbreak in Okinawa of Japan, DH had stepped up efforts to raise public awareness through multiple channels including press releases, press conference, radio interviews and social media messages. People who intend to travel to Okinawa are advised to review their vaccination history and past medical history. For those with incomplete vaccination, unknown vaccination history or unknown immunity against measles, they are advised to consult their doctor for advice on measles vaccination at least two weeks before departure. If pregnant women and women preparing for pregnancy are non-immune to measles, they are advised not to travel to Okinawa during the outbreak. As children aged under one year are generally susceptible to measles, they are also advised not to travel to Okinawa during the outbreak. For further information on measles and MMR vaccination, please visit the CHP’s designated webpage on measles: https://www.chp.gov.hk/en/features/100419.html.

References 1World Health Organization. Fact sheet on measles. April 2018. Available at http://www.who.int/immunization/diseases/measles/en/, accessed on May 8, 2018. 2World Health Organization Regional Office for Europe. Press release: Europe observes a 4-fold increase in measles cases in 2017 compared to previous year. February 2018. Available at: http://www.euro.who.int/en/media-centre/sections/press-releases/2018/europe-observes-a-4-fold- increase-in-measles-cases-in-2017-compared-to-previous-year, accessed on May 8, 2018. 3World Health Organization. Measles and Rubella Surveillance Data. Distribution of measles cases by country and by month, 2011-2018. Available at: http://www.who.int/immunization/monitoring_surveillance/burden/vpd/surveillance_type/active/measles_monthlydata/en/, accessed on May 8, 2018. 4Government of Okinawa Prefecture. Update on measles situation in Okinawa (as of May 7, 2018). Available at: http://www.pref.okinawa.jp/site/hoken/eiken/kikaku/kansenjouhou/measles.html, accessed on May 8, 2018. 5Government of Aichi Prefecture. Update on measles cases in Aichi Prefecture (as of May 6, 2018). Available at: http://www.pref.aichi.jp/soshiki/kenkotaisaku/0000013280.html, accessed on May 8, 2018. 6Taiwan Centers for Disease Control. Press release: 5今日新增 (2018-04-18).例麻疹確定病例，疾管署持續監測疫情及接觸者健康情形 Available at: https://www.cdc.gov.tw/Professional/info.aspx?treeid=D3F5DF5A9DA8C3E2&nowtreeid=E10CAEA0BB1DC4B3&tid=1FD7FA7D1C5DDDE2, accessed on May 8, 2018.

Hand Hygiene Awareness Day (May 5, 2018): It’s in your hands - prevent sepsis in healthcare Reported by Dr Betty WY CHEUNG, Medical and Health Officer, Dr Queenie KM AU, Senior Medical and Health Officer, and Dr TY WONG, Head, Infection Control Branch, CHP.

Proper hand hygiene is the key element to infection prevention and control in both the healthcare settings and in the community. Since 2005, Hong Kong has pledged support to the World Health Organization (WHO)’s first Global Patient Safety Challenge: Clean Care is Safer Care, and we have committed to promote good hand hygiene for better infection prevention and control. Starting from 2010, the Hand Hygiene Awareness Day has been marked annually on the May 5 in Hong Kong. It is the

COMMUNICABLE DISEASES WATCH 38 Apr 22 - May 5 2018 WEEKS 17 - 18 VOL 15 ISSUE NO 9 9th Anniversary of the Hand Hygiene Awareness Day in Hong Kong this year. Once again, we are launching the theme as set up by WHO every year and the theme on hand hygiene by WHO in this year is:

It’s in your hands - prevent sepsis in health care

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. If not recognised early and managed promptly, it can lead to severe consequences in term of morbidity and mortality. Sepsis frequently results from infections acquired in the healthcare settings, these infections are also called healthcare associated infections (HAIs). According to WHO, one in every 10 patients is affected by HAIs and HAIs are major safety concern nowadays. HAIs can affect patients in all types of healthcare settings where they receive care, this also includes occupational infection suffered by the healthcare workers. The effects of HAIs are very severe as they result in increased resistance of microorganisms to antimicrobials, prolonged hospital stays, unnecessary suffering of patients and additional costs on the healthcare systems. HAIs are avoidable and hand hygiene is the simplest, most effective way to reduce the chance of catching these infections.

This year, the Centre for Health Protection (CHP) of the Department of Health (DH) developed a series of promotional materials to enhance and sustain hand hygiene practice among healthcare workers and general public. A video named “Great thanks to our cleaned healing hands” has been produced. In the video, importance of hand hygiene to prevent HAIs is highlighted. Healthcare worker representatives across public and private healthcare systems in Hong Kong, including DH, the Hospital Authority, private hospitals, universities and primary care practitioners in Hong Kong took part in this production. This video has been uploaded to the CHP’s website,YouTube channel, Facebook page and broadcasted in various healthcare facilities.

Brand-new designed hand hygiene banners were also produced and delivered to public and private hospitals for hand hygiene promulgation. Public could access the latest information on Hand Hygiene Awareness Day 2018 through the CHP’s thematic website on Hand Hygiene Awareness Day (https://www.chp.gov.hk/en/features/100352.html).

Working together in hand hygiene promotion is important. CHP would like to take this opportunity to thank all participants in the production of hand hygiene video and stakeholders for their unfailing support in promoting proper hand hygiene. Some photos taken during video shooting are attached here to share with you our effort and joy.

Photos taken in the production of hand hygiene video

Participation in hand hygiene video shooting at the Queen Elizabeth Hospital (left 1st); Hong Kong Adventist Hospital-Stubbs Road (left 2nd); Faculty of Medicine,The (left 3rd) and Faculty of Medicine,The Chinese University of Hong Kong (left 4th).

Photos of hand hygiene sanitising relay in DH on March 29, 2018

COMMUNICABLE DISEASES WATCH 39 Apr 22 - May 5 2018 WEEKS 17 - 18 VOL 15 ISSUE NO 9 NEWS IN BRIEF

A local sporadic case of Hantavirus infection

On April 28, 2018, the Centre for Health Protection (CHP) recorded a sporadic case of Hantavirus infection affecting a 55-year-old man with unremarkable past health. He presented with fever, headache and coryzal symptoms on April 15. He was admitted to a public hospital on April 22 and blood tests showed acute kidney injury and thrombocytopenia. His paired blood samples collected on April 22 and 25 were both tested positive for hantavirus IgM and showed more than four-fold rise in hantavirus polyvalent antibody titre (80 to 1 280). His condition improved and he was discharged on April 28.

He travelled alone to Busan, Korea from March 13 to 15. The patient was an engineer and he noticed rodents at a refuse transfer station in West Kowloon during work in early April. However, he did not have direct contact with rodents or their excreta. He did not keep pets at home and denied any previous skin wounds. He lived with his wife and two daughters. His home contacts and other colleagues were asymptomatic. The Food and Environmental Hygiene Department was informed and investigations are ongoing.

Two sporadic cases of necrotising fasciitis caused by Vibrio vulnificus

CHP recorded two cases of necrotising fasciitis caused by Vibrio vulnificus on May 2 and 3, 2018.

The first case was an 89-year-old female with underlying illnesses. She presented with left ring finger painful swelling on April 27 and was admitted to a public hospital on April 28. Incision & drainage and amputation of left ring finger were performed on April 28 and April 30 respectively. The clinical diagnosis was necrotising fasciitis. She was treated with antibiotics and her condition was stable. The wound swab at her left ring finger collected on April 28 grew Vibrio vulnificus. She had history of injury to her left ring finger by a raw fish at home on April 27.

The second case was a 73-year-old female with underlying illnesses. She presented with fever, left knee swelling and pain on April 30 and was admitted to a public hospital on May 2. Surgical debridement was performed on the same day and she was admitted to the intensive care unit for post-operative care. The clinical diagnosis was necrotising fasciitis. She was treated with antibiotics and her condition was critical. Left leg tissue collected on May 2 grew Vibrio vulnificus. She had history of visiting wet market but did not report injury by marine products.

Both cases had no recent travel history and their home contacts were asymptomatic.

A local sporadic case of listeriosis

On May 3, 2018, CHP recorded a case of listeriosis affecting a 75-year-old woman with underlying illnesses. She was admitted to a public hospital for management of her underlying illness on April 3 and was transferred to another public hospital on April 7 for further management. She developed fever on April 29 and blood culture collected on the same day yielded Listeria monocytogenes. She was treated with antibiotics and her condition was stable. She had no travel history and no history of consumption of high risk food item during the incubation period. Her home contact was asymptomatic. Investigations are ongoing.

A sporadic confirmed case of brucellosis

On May 4, 2018, CHP recorded a confirmed case of Brucellosis affecting a 55-year-old woman with underlying illnesses. She presented with worsened low back pain and urinary incontinence on April 17 and was admitted to a public hospital on April 24. She was found to have fever and right lower limb weakness on admission. Magnetic resonance imaging of the lumbar spine showed no infective foci.The clinical diagnosis was spinal stenosis with cauda equina syndrome. She was discharged on April 26. Subsequently, her blood sample collected on April 24 grew Brucella melitensis and she was called back for admission on May 1. She was treated with antibiotics and her condition was stable.The patient had travelled with her daughter-in-law to Zhaoqing for a few days in February 2018 but she forgot the details. No risk factor was identified. Her home contacts and travel collateral were asymptomatic.

COMMUNICABLE DISEASES WATCH 40 May 6 - May 19 2018 WEEKS 19 - 20 VOL 15 ISSUE NO 10

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Scientific Committee’s Recommendations on Seasonal Influenza Vaccination for the 2018/19 Season in Hong Kong Reported by Dr Cindy POON, Medical and Health Officer, Vaccine Preventable Disease Office, Surveillance and Epidemiology Branch, CHP.

The Scientific Committee on Vaccine Preventable Diseases (SCVPD) under the Centre for Health Protection (CHP) of the Department of Health has reviewed the local epidemiological data, the latest scientific evidence of influenza vaccination as well as overseas experiences, and came up with its recommendations on the use of seasonal influenza vaccine (SIV) for the coming influenza season (2018/19) in Hong Kong.

Given that influenza vaccination is one effective means in preventing influenza and its complications, as well as reducing influenza-associated hospitalisation and death, SCVPD recommends that all members of the public aged six months or above, except those with known contraindications, should receive SIV annually for personal protection, preferably before the winter influenza season which usually started in January from the local epidemiology. One should only receive SIV once in the 2018/19 season, which is in line with all along the World Health Organization’s (WHO) recommendation.

Vaccine composition The composition of the 2018/19 quadrivalent influenza vaccine (northern hemisphere winter) comprises an A/Michigan/45/2015 (H1N1)pdm09-like virus, an A/Singapore/INFIMH-16-0019/2016 (H3N2)-like virus, a B/Colorado/06/2017-like virus (B/Victoria/ 2/87 lineage), and a B/Phuket/3073/2013-like virus (B/Yamagata/16/88 lineage). The influenza B virus component of trivalent influenza vaccine for use in the 2018/19 season should be a B/Colorado/06/2017-like virus of the B/Victoria/2/87-lineage. The above compositions are in line with the recommendations made by WHO for the 2018/19 Northern Hemisphere influenza season. Based on local laboratory data, trivalent SIV may potentially prevent majority of influenza burden in Hong Kong on average, while quadrivalent SIV may potentially offer additional protection against influenza B.

Vaccine type The SIVs that are currently registered in Hong Kong can be broadly classified into inactivated influenza vaccines (IIVs) and live attenuated influenza vaccines (LAIV). Most IIVs are given via the intramuscular route and are recommended for use in individuals six months of age or above except those with known contraindications (depending on individual brand). LAIV was once available in Hong Kong from 2009 to 2013 but it was discontinued in the local market afterwards. Recently, a LAIV (Flumist) has been registered again in Hong Kong in April 2018. Flumist should be given intranasally and is registered for use in individuals aged two to 49 years. In all circumstances, the package inserts for individual products should always be referred to when deciding which vaccine to give, the dosage and the precautions.

Adverse events following IIV administration may include local reactions such as pain, redness and swelling at the site of injection (15 to 20%). Non-specific systemic symptoms including fever, chills, malaise and myalgia are reported in less than 1% of IIV recipients. Guillain-Barré syndrome (GBS) occurs rarely after immunisation and extensive reviews showed that there is inadequate evidence to accept or reject a causal relationship between influenza vaccine and GBS. Nonetheless, scientific studies have shown that influenza infection can be complicated with GBS, and influenza infection per se can pose a much greater risk of GBS than that following influenza vaccination.

For LAIV, the most common adverse reactions are nasal congestion or runny nose in all ages, fever in children and sore throat in adults. The safety in pregnant women has not been established. Children aged below five years with recurrent wheezing/ persons of any age with asthma may be at an increased risk of wheezing following administration. LAIV can be used among non-pregnant and non-immunocompromised people two to 49 years of age. However, unlike IIVs, LAIV has not been used extensively in Hong Kong before. If healthcare providers choose to use LAIV, they should consider the contraindications and precautions.

COMMUNICABLE DISEASES WATCH 41 May 6 - May 19 2018 WEEKS 19 - 20 VOL 15 ISSUE NO 10 Vaccine effectiveness (VE) According to WHO, when the vaccine strains closely match the circulating influenza viruses, efficacy of IIV in individuals younger than 65 years of age typically range from 70% to 90%, whereas the efficacy of IIV to prevent influenza infection in individuals aged 65 years or above is at best modest, irrespective of setting, population and study design.

Locally, in the 2017/18 season, CHP has collaborated with the private medical practitioners participating in the sentinel surveillance system to study the VE of IIV at primary care setting using the test-negative case-control method. Nearly 900 specimens were received in the five months from November 2017 to March 2018, with 54% tested positive for influenza and 78% of the positive influenza detections were influenza B.The overall VE among all ages was 59.1% (95% confidence interval [CI]: 41.1 to 71.8) against all influenza, and 53.5% (95% CI: 35.4 to 74.6) against influenza B.The results showed that the IIV for the 2017/18 season offered a moderate to good protection against laboratory-confirmed influenza at primary care level in the 2017/18 winter influenza season in Hong Kong.

Priority groups

Based on a range of scientific considerations, as well as taking into account local disease burden and international experience, SCVPD recommends the following priority groups for seasonal influenza vaccination in 2018/19 season:-

Pregnant women; Elderly persons living in residential care homes; Long-stay residents of institutions for persons with disability; Persons aged 50 years or above; Persons with chronic medical problems*; Health care workers; Children aged six months to 11 years; Poultry workers; and Pig farmers and pig-slaughtering industry personnel.

*People with chronic medical problems mainly refer to those who have chronic cardiovascular (except hypertension without complication), lung, metabolic or kidney disease, obesity# (BMI 30 or above), who are immunocompromised^, children and adolescents (aged six months to 18 years) on long-term aspirin therapy, and those with chronic neurological condition that can compromise respiratory function or the handling of respiratory secretions or that can increase the risk for aspiration or those who lack the ability to take care for themselves. Seasonal influenza vaccination is recommended for their increased risk of complications and death associated with influenza infection. #Obesity is considered as an independent risk factor for influenza complication and thus people with BMI 30 or above are included for seasonal influenza vaccination. ^People who are immunocompromised refer to those with a weakened immune system due to disease (such as HIV / AIDS) or treatment (such as cancer treatment).

People who are in the priority groups are generally at increased risk of severe influenza or transmitting influenza to those at high risk. Therefore, they shall have higher priority for seasonal influenza vaccination.

In the coming 2018/19 season, the Government will continue to provide free and subsidised influenza vaccination to eligible groups through the Government Vaccination Programme and the Vaccination Subsidy Schemes respectively.The details of various vaccination programmes will be announced in due course.

For the full version of the SCVPD’s Recommendations on Seasonal Influenza Vaccination for the 2018/19 Season in Hong Kong, please visit the CHP’s website at https://www.chp.gov.hk/files/pdf/scvpd_recommendations_on_siv_for_2018_19_season.pdf.

Infection control for ambulatory healthcare facilities Reported by Mr Anthony NM NG, Senior Nursing Officer, Dr Edman TK LAM, Senior Medical and Health Officer, and Dr TY WONG, Head, Infection Control Branch, CHP.

Over the past decades, there is a significant development and expansion in healthcare delivery by a variety of outpatient, ambulatory, community-based settings in Hong Kong. It is very important to emphasise that all healthcare settings, regardless of the level of care provided, must make infection control a priority to ensure quality and patient safety.

In the first place, all ambulatory healthcare facilities should be designed, constructed, furnished and equipped to minimise the risk of transmitting infection, and facilitate implementation of infection prevention and control measures. Physical layout and workflow of various patient care procedures should be considered in advance. Furthermore, there should be a person with relevant training and experience to oversee the overall infection control practice, including risk assessment and management; development of infection prevention and control policies and plans based on the identified risks; provision of relevant education COMMUNICABLE DISEASES WATCH 42 May 6 - May 19 2018 WEEKS 19 - 20 VOL 15 ISSUE NO 10 and training to all relevant staff; mechanisms for identification, reporting and managing work-related incidents in respect of infection control; implementation of all reasonable steps to protect staff from work-related diseases; monitoring of the implementation of safe systems of work; compliance with relevant legislation and disease reporting requirements.

In general, there are two tiers of precautions to prevent transmission of infectious agents in ambulatory healthcare facilities: standard precautions and transmission-based precautions. The first tier standard precautions are the minimum infection prevention practices that apply to all patients, regardless of their diagnosis and infectious status, in any setting where healthcare is delivered. The second tier transmission-based precautions are used in addition to standard precautions, where the suspected or confirmed presence of infectious agents represents an increased risk of transmission.

Standard precautions define all the steps that should be taken to prevent spread of infection from person to person or from contaminated environmental surfaces/ healthcare items, when there is an anticipated contact with blood; body fluids; secretions; excretions, such as urine and faeces (excluding sweat) whether or not visibly contaminated with blood; non- intact skin, such as an open wound; and mucous membranes, such as the oral cavity. Standard precautions include hand hygiene; use of personal protective equipment (PPE); respiratory hygiene and cough etiquette; appropriate patient placement; safe injection practices, sharps handling and disposal; cleaning and disinfection of environment; reprocessing of reusable medical devices; waste management; and handling of linen. Poster on standard precautions.

Since the infectious agent is often not known at the time of encounter in clinic settings, transmission-based precautions are used empirically, according to the clinical syndrome and the likely etiologic agents at that time. Systems should be in place for early detection and management of potentially infectious patients which include prompt isolation, referral and transfer as appropriate.

There are three categories of transmission-based precautions: (1) Contact Precautions, in which gloves and gown should be worn during care of patients with suspected infections or contact with infected materials; examples of infections transmitted by contact route include scabies, norovirus, methicillin resistant Staphylococcus aureus (MRSA), Vancomycin-resistant enterococci (VRE) and difficile, (2) Droplet Precautions, in which surgical mask should be worn during care of patients with suspected infections within one meter distance; examples of infections transmitted by droplet route include influenza, Group A streptococcus, pertussis and rubella, and (3) Airborne Precautions, in which besides special air handling and ventilation, N95 respirator should be worn during care of patients with suspected airborne infections or when performing aerosol generating procedures; examples of airborne infections are pulmonary tuberculosis, chickenpox, measles and disseminated herpes zoster. Transmission-based precautions are applied in addition to standard precautions and using appropriate types of PPE. For some diseases that can be transmitted in multiple ways, a combination of transmission-based Signages on transmission-based precautions. precautions may be used.

Education and training on the principles and rationale for recommended practices are critical elements of standard precautions and transmission-based precautions because they facilitate appropriate decision-making and promote adherence. Relevant information, such as infection prevention and control policy, infection control basic principles and related work practice protocols, incident management, manufacturers’ instructions, training materials, evidence based guidelines, standards and regulations, should be readily available. Related education and training should be provided upon induction and orientation; repeated regularly; and at any time when information has been updated or revised. Furthermore, adequate resources should be available to facilitate the implementation of standard precautions and transmission-based precautions, including hand hygiene facilities, especially alcohol-based hand rub at points of care; hand hygiene technique posters; adequate and appropriate PPE stockpile; PPE donning and doffing posters, and visual alerts on respiratory hygiene and cough etiquette; lidded waste receptacles; sharps boxes and clinical waste disposal; supply of cleaning equipment and environmental disinfectants; proper maintenance and monitoring of steam sterilisers; and designated areas for patient placement and sterile storage. An infection control checklist can be used as an audit tool for monitoring of the implementation of safe systems of work.

For more information on infection control for ambulatory healthcare facilities, please refer to the “Guide to Infection Control in Clinic Setting”, which is accessible at https://www.chp.gov.hk/files/pdf/guide_to_infection_control_in_clinic_setting.pdf. The Guide was issued by the Infection Control Branch of the Centre for Health Protection of the Department of Health (DH), with key references taken from DH, Hospital Authority, World Health Organization, United States Centers for Disease Control and Prevention, and United Kingdom Department of Health. The Guide serves to provide guidance to healthcare personnel on prevention and control of infection in clinic settings, where medical and dental services are provided to outpatients. It is intended for use as a general guidance. One must exercise judgment in applying the Guide for their own particular circumstances and seeks professional/ expert advice where appropriate.

COMMUNICABLE DISEASES WATCH 43 May 6 - May 19 2018 WEEKS 19 - 20 VOL 15 ISSUE NO 10 NEWS IN BRIEF

Two local confirmed cases of human myiasis

From November 1, 2017 to April 30, 2018, the Centre for Health Protection (CHP) recorded two cases of human myiasis. The first case was a 92-year-old woman with underlying illnesses. She had history of left foot gangrene and presented with left foot pain on November 23, 2017. She was admitted to a public hospital the following day. Maggots were removed from the wound over 4th web space of the left foot, which were subsequently identified to be fly larvae belonging to Phoridae family. The diagnosis was left foot myiasis and wet gangrene. Her condition deteriorated and she passed away on December 28, 2017. The patient lived with family and her family members were asymptomatic. She did not travel during the incubation period. Health advice on personal and environmental hygiene was given to the family.

The second case was a 58-year-old man with underlying illnesses. He presented with pain and swelling over dorsum of right foot in end of March, 2018. He developed fever on April 30, 2018 and was admitted to a public hospital on the same day.Two maggots were removed from the wound over the 2nd web space of his right foot, which were subsequently identified as immature (second instar) fly larvae belonging to suborder Cyclorrhapha. The diagnosis was right foot myiasis and wet gangrene. He was treated with antibiotics and right below knee amputation was performed. He required post-operative intensive care. He remained hospitalised and his condition was stable. He lived alone and had no recent travel history. Health advice on wound care and personal and environmental hygiene was given to the patient.

A local sporadic case of listeriosis

On May 13, 2018, CHP recorded a sporadic case of listeriosis affecting a 79-year-old woman with underlying illnesses. She presented with fever on May 10 and was admitted to a public hospital on the same day. Her blood specimen collected on May 11 grew Listeria monocytogenes. The clinical diagnosis was sepsis and she was treated with antibiotics. Her condition remained stable. She had no recent travel history. She did not recall consuming high risk food during the incubation period. Her household contacts remained asymptomatic.

CA-MRSA cases in April 2018

In April 2018, CHP recorded a total of 96 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 52 males and 44 females with ages ranging from 25 days to 68 years (median: 36 years).Among them, there were 69 Chinese, 6 Caucasian, 6 Filipinos, 3 Pakistani, 2 Indonesian, 1 African, 1 Indian, 1 Korean, 1 Nepalese, 1 Vietnamese, and 5 of unknown ethnicity.

Ninety-five cases presented with uncomplicated skin and soft tissue infections while the remaining case had severe CA-MRSA infection.The severe case affected a 34-year-old woman who presented with right loin pain, fever, chills and rigor since March 25. She was admitted to a public hospital on April 4. Radiological imaging of her abdomen showed a right renal abscess. She was treated with percutaneous drainage of abscess and antibiotics. Her blood specimen collected on April 5 and pus specimen from the abscess collected on April 7 were both cultured positive for CA-MRSA. She was diagnosed with renal abscess complicated with septicaemia. She remained in a stable condition and was discharged on April 27.

Separately, the isolate of a case was found to be resistant to mupirocin.The case involved a 32-month-old boy who had right thumb abscess and cellulitis in early April. He recovered after treatment with antibiotics and surgical drainage.

Among the 96 cases, one was a nurse working in a general out-patient clinic. Investigation did not reveal any epidemiologically linked cases. Besides, three household clusters, with each affecting two persons, were identified.

Scarlet fever update (April 1, 2018 – April 30, 2018)

Scarlet fever activity in April decreased as compared with that in March. CHP recorded 125 cases of scarlet fever in April as compared with 150 cases in March. The cases recorded in April included 78 males and 47 females aged between three months and 35 years (median: five years).There were two institutional clusters occurring in two kindergartens, each affecting three children. No fatal cases were reported in April.

COMMUNICABLE DISEASES WATCH 44 May 20 - Jun 2 2018 WEEKS 21 - 22 VOL 15 ISSUE NO 11

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Updated situation of Ebola Virus Disease in Democratic Republic of Congo Reported by Dr Eric LAM, Medical and Health Officer, and Dr Philip WONG, Senior Medical and Health Officer, Communicable Disease Surveillance and Intelligence Office, Surveillance and Epidemiology Branch, CHP.

On May 8, 2018, an Ebola Virus Disease (EVD) outbreak was notified to the World Health Organization (WHO) by the Ministry of Health (MoH) of the Democratic Republic of Congo (DRC). At the time of notification, more than 30 cases have been identified since early April 2018, among which two were confirmed by laboratory test.

Up till June 3, 2018, there were a total of 56 reported cases, including 25 deaths. The outbreak so far remained localised to Équateur Province which is located in the northwestern part of DRC and adjacent to the Republic of Congo (Figure 1). The majority of cases were reported in Bikoro health zone (26 cases), followed by Iboko health zone (25 cases) and Wangata health zone (five cases). Of Figure 1 - Affected areas in the latest EVD outbreak in DRC. (Image by note, one confirmed case in Wangata was in the provincial Communicable Disease Information System Office, Centre for Health Protection of capital - Mbandaka, a large urban centre located on the the Department of Health) Congo River which is a major national and international river, with road and air transport axes.

Among all the cases, 37 have been confirmed by laboratory test. Figure 2 and Figure 3 show the epidemic curve and age distribution of the cases respectively. A total of five healthcare workers were affected. As of May 31, 2018, 880 contacts have been identified and were being followed-up1.

In view of the increased risk of further disease transmission, a meeting of the International Health Regulations (IHR) Emergency Committee was convened by WHO on May 18, 2018. It was Figure 2 - Epidemic curve of the EVD outbreak in Equateur Province, DRC, as of June 3, 2018. (Source of information:WHO) concluded that the outbreak did not constitute a Public Health Emergency of International Concern (PHEIC) at this moment.

According to the latest assessment by WHO, the overall public health risk is very high at the national level due to the serious nature of the disease, insufficient epidemiological information and the delay in the detection of initial cases, which make it difficult to assess the magnitude and geographical extent of the outbreak. The risk at regional level is considered to be high due to the increased risk of further spread within DRC and to neighbouring countries by the confirmed case in Mbandaka. However, the risk is considered to be low at the global level currently. WHO has also advised against Figure 3 - Confirmed and probable EVD cases by age and sex, DRC, as application of any travel or trade restrictions on DRC. of June 3, 2018. (Source of information:WHO) COMMUNICABLE DISEASES WATCH 45 May 20 - Jun 2 2018 WEEKS 21 - 22 VOL 15 ISSUE NO 11

EVD is caused by Ebolavirus which belongs to the virus family Filoviridae. There are five species within the genus Ebolavirus, but historical outbreaks in Africa were caused by three of them, namely: Bundibugyo ebolavirus, Sudan ebolavirus and Zaire ebolavirus2. The largest outbreak of EVD occurring from 2014 to 2016 in West Africa since its discovery in 1976 was caused by the Zaire ebolavirus. It has resulted in over 28 000 cases and more than 11 000 deaths. The latest outbreak in DRC is also caused by the Zaire ebolavirus.

Ebolavirus is transmitted to humans through close contact with blood, secretions, organs or other bodily fluids of its natural host (fruit bats), infected animals or infected humans. The incubation period ranges from two to 21 days. Clinical manifestation is characterised by sudden onset of fever, intense weakness, muscle pain, headache and sore throat, followed by vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, internal and external bleeding. There is no specific treatment for the disease. EVD in humans has an average case fatality rate of around 50%.

Sexual transmission has been reported with Ebolavirus. Based on present evidence, WHO recommends that survivors of EVD and their sexual partners should either abstain from all types of sex, or practise safe sex through correct and consistent condom use for 12 months from onset of symptoms or until the semen tests negative twice for Ebolavirus2.

This EVD outbreak was the 9th EVD outbreak in DRC, with a recent one occurring in May 2017.The number of cases recorded in EVD outbreaks in DRC in the past decade (2008 to 2017) ranged from eight to 693.

In the wake of multiple EVD outbreaks in the country, the government of DRC is better prepared to mount responses to control and prevent the spread of EVD. Other international non-government organisations have worked with WHO to offer rapid and substantive support to DRC, including technical expertise and logistical assistance.

In addition to the measures employed in previous EVD outbreaks, such as enhanced disease surveillance and diagnostic capability, strengthened community engagement and sustained practice of safe and dignified burials, the MoH of DRC have initiated vaccination campaign with the support of WHO in the affected areas since May 21, 2018.The vaccination was targeted at the contacts of infected people, including health care workers. The vaccine used was recombinant vesicular stomatitis virus–Zaire Ebola virus (rVSV-ZEBOV) vaccine. This vaccine was yet to be licensed, but had been shown to be highly protective against Ebola virus in a major trial led by WHO in Guinea in 20154. A ring vaccination strategy was implemented targeting all the contacts and contacts of contacts of a recently confirmed case. As of June 3, a total of 1 199 people have been vaccinated1.

In Hong Kong, EVD has become a notifiable disease under the disease group of “viral haemorrhagic fever” since 2008. All registered medical practitioners are required to notify the Centre for Health Protection (CHP) of the Department of Health all suspected or confirmed cases of EVD.As of June 5, 2018, there has been no confirmed case of EVD recorded in the locality.

With the evolving situation in DRC, the Hong Kong Government has been maintaining due vigilance and continues to keep abreast of the latest developments concerning EVD. Risk assessment is conducted continuously to inform appropriate public health measures, with regular review on the Preparedness and Response Plan for EVD as appropriate.

There is no specific treatment for EVD, nor licensed vaccine to prevent EVD yet. To prevent the infection of Ebolavirus, it is important for members of the public to observe the following:

✦ Observe good personal and environmental hygiene; ✦ Wash the hands with liquid soap or clean with alcohol-based handrub; ✦ Avoid close contact with feverish or ill persons, and avoid contact with blood or bodily fluids of patients, including items which may have come in contact with an infected person's blood or bodily fluids; ✦ Cook food thoroughly before consumption; and ✦ Avoid contact with animals.

References 1Ebola Situation Report – June 5, 2018,World Health Organization. Available at http://apps.who.int/iris/bitstream/handle/10665/272761/SITREP-EVD-DRC-20180605-eng.pdf?ua=1, accessed on June 6, 2018. 2Factsheet Ebola virus disease,World Health Organization. Available at: http://www.who.int/news-room/fact-sheets/detail/ebola-virus-disease, accessed on June 6, 2018. 3Ye a r s o f E b o l a V i r u s D i s e a s e O u t b re a k s , U S C D C . Av a i l a b l e a t : https://www.cdc.gov/vhf/ebola/history/chronology.html, accessed on June 6, 2018. 4Final trial results confirm Ebola vaccine provides high protection against disease, Press Release,World Health Organization. Available at: http://www.who.int/mediacentre/news/releases/2016/ebola-vaccine-results/en/, accessed on June 6, 2018.

COMMUNICABLE DISEASES WATCH 46 May 20 - Jun 2 2018 WEEKS 21 - 22 VOL 15 ISSUE NO 11 Updated Guidelines on Malaria Chemoprophylaxis for Travellers from Hong Kong Reported by Dr Karen LAM, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Facts on malaria

Malaria is caused by the protozoan parasite Plasmodium and is transmitted by female Anopheles mosquitoes. Human malaria can be caused by five species of Plasmodium, namely P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi. P. knowlesi is a species that normally infects animals but can occasionally infect humans1. The incubation period ranges from seven days to several months or more1. Symptoms of malaria include fever, chills, headache, muscle pain and weakness, cough, jaundice, anaemia, vomiting, diarrhoea and abdominal pain1. Severe malaria is usually caused by P. falciparum and may manifest as generalised convulsion, circulatory collapse, coma and organ failure such as acute renal failure. Malaria caused by P. knowlesi might manifest atypically, and organ failure and sporadic fatal outcomes have been reported. Diagnosis and treatment should be sought promptly to avoid complications or fatality. Young children, pregnant women, immunocompromised people, people with co-morbidities and travellers from non-endemic areas are most vulnerable to malaria infection.

The Working Group on Malaria Prophylaxis and the Scientific Committee on Vector-borne Diseases under the Centre for Health Protection (CHP) of the Department of Health recently reviewed the global and local epidemiology of malaria, examined the preventive measures and updated the guidelines on malaria chemoprophylaxis for travellers from Hong Kong.The updated guideline serves as a local guideline for reference by doctors in Hong Kong who provide advice, or prescribe malaria chemoprophylaxis, to travellers from Hong Kong who go to malaria endemic areas.This article summarised the latest situation of malaria and the main points of the updated guideline.

Global and local situation of malaria Malaria is a common and serious infection in many tropical and subtropical areas. According to the World Health Organization (WHO), in 2016, 91 countries and areas had ongoing malaria transmission, and there were an estimated 445 000 deaths from malaria globally, of which 407 000 (approximately 91%) were in the WHO African Region2. While most malaria cases and deaths occurred in sub-Saharan Africa, other WHO regions including South-East Asia, Eastern Mediterranean, Western Pacific and the Americas were also at risk2.

In Hong Kong, malaria is a notifiable infectious disease under the Prevention and Control of Disease Ordinance (Cap 599).The last local indigenous case was recorded in 1998. From 2008 to 2017, CHP recorded a total of 268 non-locally acquired cases with the annual number ranging from 20 to 41 (Figure 1). In 2018, six cases were recorded (as of June 1). The 274 patients comprised 204 (74%) males and 70 (26%) females. Their ages ranged from two to 90 years (median: 35 years). All cases, except one unclassified case recorded in 2015, were imported infections. The unclassified case involved a 90-year-old woman who had recrudescence of old infection. The five most common places of infection of the imported cases were India (86 cases), Nigeria (31 cases), Pakistan (27 cases), Ghana (14 cases) and Kenya (9 cases). P. falciparum was the most commonly identified parasite (132 cases, 48.2%), followed by P. vivax (121 cases, 44.2%), P. malariae (11 cases, 4.0%), and P. ovale (4 cases, 1.5%). No case caused by P. knowlesi was recorded so far. From 2008 to 2018 (as of June Figure 1 - Number of malaria cases in Hong Kong from 2008 1), there were four fatal cases giving a case fatality rate of 1.5%. to 2018 (*provisional figure as of June 1).

Prevention of malaria The majority of infections and deaths due to malaria are preventable. There is currently no registered vaccine against malaria. The five principles of malaria prevention include: (i) being aware of the risk, (ii) avoiding mosquito bites, (iii) taking malaria chemoprophylaxis where appropriate, (iv) prompt diagnosis and treatment, and (v) avoiding outdoor activities in environments that are mosquito breeding places.

COMMUNICABLE DISEASES WATCH 47 May 20 - Jun 2 2018 WEEKS 21 - 22 VOL 15 ISSUE NO 11 The first line of defence against malaria is to take protective measures to reduce contact with mosquitoes in areas with malaria risk. Measures to prevent mosquito bites include mosquito avoidance, physical barriers, chemical barriers and the use of insecticides. Insect repellents containing N,N-diethyl-3-methylbenzamide (commonly known as DEET), IR3535 or Icaridin (also known as Picaridin) are recommended for all travellers at risk of exposure. When using any insect repellent, the label instructions and precautions should be followed. DEET-containing insect repellents should be applied to exposed parts of the body and clothing in accordance with label instructions and precautions. For children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic and where exposure is likely, those aged two months or above can use DEET-containing insect repellents with a concentration of DEET up to 30%. However, DEET-containing insect repellents should not be used in infants under two months of age and alternative measures to prevent mosquito bites should be adopted.

Guidelines on malaria chemoprophylaxis for travellers from Hong Kong Travellers who go to malaria endemic areas should arrange a medical consultation at least six weeks before the trip for preventive measures and assessment of the need of anti-malarial prophylaxis. The prescription of malaria chemoprophylaxis depends on several factors including but not limited to the destinations, itinerary, time of travel, types of activities and past medical history of the traveller. If malaria chemoprophylaxis is required, it should be started before the trip, continued throughout the journey and until one to four weeks after leaving the area according to the doctor’s instruction. Special considerations are warranted in people with special host factors such as pregnancy, glucose-6-phosphate dehydrogenase (G6PD) deficiency, breast-feeding, infection with human immunodeficiency virus (HIV), pre-existing chronic disease and concomitant use of other medications.

Malaria in a pregnant woman increases the risk to both the mother and the fetus. Pregnant women are advised to avoid travelling to malaria endemic areas. If travel is unavoidable, pregnant women should adopt effective measures including mosquito bite prevention and chemoprophylaxis. In general, the risk of malaria to both mother and fetus far outweighs any potential teratogenic effect.

HIV infection impairs immune response to malaria and increases both the incidence and severity of malaria, whereas acute malaria stimulates HIV replication, resulting in increased viral loads that may hasten disease progression and increase transmission risk of HIV3. Therefore, it is important for people with HIV infection to take prevention measures against malaria through avoidance of mosquito bites and the use of chemoprophylaxis. Commonly used integrase inhibitors and nucleoside reverse transcriptase inhibitor combinations nowadays have not shown any known interaction with drugs used for malaria chemoprophylaxis.

If malaria chemoprophylaxis is to be prescribed, the doctor should be aware of all the medications that the traveller is taking and ensure that none of them interacts significantly with the choice of malaria chemoprophylaxis. Doctors are advised to refer to the package insert of individual drugs and may consider taking reference from online resources for information on drug interactions.

Healthcare professionals are encouraged to refer to the Guidelines on Malaria Chemoprophylaxis for Travellers from Hong Kong developed by the Working Group on Malaria Prophylaxis under the Scientific Committee on Vector-borne Diseases (https://www.chp.gov.hk/files/pdf/guidelines_on_malaria_chemoprophylaxis_for_travellers_from_hong_kong_201804.pdf) and the latest Global Malaria Risk Summary (https://www.chp.gov.hk/en/static/24009.html) when giving travel health advice to travellers from Hong Kong who go to malaria endemic areas.

References 1World Health Organization. International Travel and Health - Chapter 7 Malaria. 2017. Available at http://www.who.int/ith/2017-ith-chapter7.pdf, accessed on April 27, 2018. 2World Health Organization. World Malaria Report. 2017. Available at: http://apps.who.int/iris/bitstream/10665/259492/1/9789241565523-eng.pdf?ua=1, accessed on Februar y 8, 2018. 3Health Canada. Canadian Recommendations for the Prevention and Treatment of Malaria Among International Travellers 2014. Available at: http://publications.gc.ca/collections/collection_2014/aspc-phac/HP40-102-2014-eng.pdf, accessed on May 14, 2018.

COMMUNICABLE DISEASES WATCH 48 May 20 - Jun 2 2018 WEEKS 21 - 22 VOL 15 ISSUE NO 11 NEWS IN BRIEF

A sporadic confirmed case of brucellosis

On May 24, 2018, the Centre for Health Protection (CHP) recorded a confirmed case of brucellosis affecting a 66 year-old woman with underlying illnesses. She presented with fever and right loin pain on May 14 and was admitted to a public hospital on May 16. Her blood culture collected after admission grew Brucella melitensis. She was treated with antibiotics. Her condition was stable and she was discharged on May 30. She had travelled to Xi’an with a friend from April 24 to May 1 and also frequently travelled to Shenzhen during the incubation period. Except for consuming hotpot with lamb once in Xi’an, she did not have other risk factors such as direct contact with goats or sheep, raw lamb or consumption of placenta. Her home contact and travel collateral remained asymptomatic.

A local sporadic case of listeriosis

On May 27, 2018, CHP recorded a sporadic case of listeriosis affecting a 54-year-old woman with underlying illnesses. She presented with fever and diarrhoea on May 25 and was admitted to a public hospital on the same day. The clinical diagnosis was sepsis and she was treated with antibiotics. Her condition remained stable. Her blood specimen collected on May 25 grew Listeria monocytogenes. She had no recent travel history. She consumed smoked in a restaurant during the incubation period but could not recall the exact place of consumption. Her household contact remained asymptomatic.

A probable sporadic case of Creutzfeldt-Jakob disease

On May 30, 2018, CHP recorded a probable case of sporadic Creutzfeldt-Jakob disease (CJD) affecting a 64-year-old woman with underlying illnesses. She had presented with progressive cognitive decline with decreased verbal response since March 2018 and was admitted to a public hospital on May 7, 2018. She was found to have progressive dementia, extrapyramidal dysfunction, rigidity, gait disturbance, dysphasia and akinetic mutism. Findings of magnetic resonance imaging of the brain and electroencephalography were compatible with CJD. Her condition remained stable in hospital. She had no known family history of CJD and no reported risk factors for iatrogenic or variant CJD were identified. She was classified as a probable case of sporadic CJD.

A sporadic case of necrotising fasciitis caused by Vibrio vulnificus

On May 30, 2018, CHP recorded a case of necrotising fasciitis caused by Vibrio vulnificus affecting a 77-year-old man with underlying illnesses. He presented with fever, right forearm swelling and pain on May 26 and was admitted to a public hospital on the same day. Blood culture collected on May 26 yielded Vibrio vulnificus. The clinical diagnosis was necrotising fasciitis. He was treated with antibiotics and surgical debridement was performed on May 27 and May 28. He required post-operative intensive care and his condition was serious. He had an abrasion injury to his right forearm on a boat on May 25. His home contacts were asymptomatic.

A sporadic case of psittacosis

On May 31, 2018, CHP recorded one sporadic case of psittacosis affecting a 65-year-old male with underlying illness. He had presented with fever and cough since May 1 and was admitted to a public hospital on May 5. The clinical diagnosis was pneumonia. He was treated with antibiotics. He remained stable and was discharged home on May 9. His nasopharyngeal swab collected on May 6 was tested positive for Chlamydophila psittaci DNA by PCR. He had travelled to Xinhui, Guangdong for a period of two days (April 22 to 23) with his family and friends. He did not report any contact history of birds or their excreta there and elsewhere in Hong Kong during the incubation period. He did not keep birds at home and his home contacts and travel collaterals were asymptomatic.

A domestic cluster of measles

In May 2018, CHP recorded a domestic cluster of measles affecting a 10-month old boy and his 42-year-old father, who resided in Futian, Shenzhen. The boy presented with fever, cough, runny nose and conjunctivitis on May 17 and rash on May 21. He came to Hong Kong on May 21 and was admitted to a private hospital from May 21 to May 25. His throat swab was tested positive for measles virus RNA. Contact tracing revealed his 42-year-old father had fever and cough on May 4 and rash on May 11. He had also been admitted to the same private hospital from May 11 to May 15 and was initially managed as infectious mononucleosis. His blood specimen subsequently taken on May 21 was tested positive for immunoglobulin M (IgM) against measles virus. Both father and son were stable all along.

Epidemiological investigation revealed that the boy had stayed in Shenzhen during the whole incubation period before he came to Hong Kong for treatment. His father travelled to Hong Kong for work on weekdays and stayed in Shenzhen after work and during weekends. The boy was born in Hong Kong and was not yet due for the first dose of Measles, Mumps and Rubella (MMR) vaccine according to the Hong Kong Childhood Immunisation Programme (HKCIP). His father who was also born in Hong Kong could not recall his vaccination history.The boy’s 33-year-old mother had fever, cough and sore throat on May 22. She did not have rash and her blood specimen taken on May 22 was tested negative for IgM and positive for IgG against measles virus. She was managed as acute pharyngitis and had recovered.The boy’s three-year-old sister remained asymptomatic and she had received the first dose of MMR according to the HKCIP. Contact tracing did not identify further cases.

COMMUNICABLE DISEASES WATCH 49 Jun 3 - Jun 16 2018 WEEKS 23 - 24 VOL 15 ISSUE NO 12

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie LAM / Dr Albert AU / DrTYWong / Dr GladysYeung / Dr PhilipWong / SimonWong / Sheree Chong / Dr Shirley Tsang / Doris Choi Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Update on Nipah Virus Infection in India Reported by Ms Sheree CHONG, Scientific Officer, Communicable Disease Surveillance and Intelligence Office, Surveillance and Epidemiology Branch, CHP.

Nipah virus infection, caused by Nipah virus (NiV), is an emerging zoonotic infection that can cause severe disease in both animals and humans1. Fruit bats of the Pteropodidae family are the natural host of NiV without apparent disease.They can shed the virus in their excretions and secretions, such as saliva, urine, semen and excreta. NiV infections have been reported in domestic animals, for example, pigs, which can act as the intermediate hosts for the transmission of the virus to humans.

Emergence of NiV causing human infections NiV was initially isolated and identified in 1999 during an outbreak of encephalitis and respiratory illness among pig farmers and people with close contact with pigs in Malaysia and Singapore. Its name was originated from Sungai Nipah, a village in Malaysia where the first human cases lived. During the 1999 outbreak, nearly 300 human cases with over 100 deaths were reported and more than a million pigs were euthanised. In this outbreak, humans were apparently infected with NiV via close contact with infected pigs which contracted the virus from bats. No person-to-person transmission was reported. No subsequent cases (in neither swine nor human) have been reported in Malaysia and Singapore after this outbreak.

Global situation in the past two decades Outbreaks of NiV have occurred in Bangladesh and India since 2001. In 2001, a NiV outbreak in humans was reported in Bangladesh2. Since then, NiV outbreaks have been reported almost every year in different districts of Bangladesh. The last outbreak was reported in 2015. From 2001 to 2015, a total of 261 human cases of NiV infection with 198 deaths (76%) were reported there. India also reported two outbreaks of NiV infection in the eastern state of West Bengal, bordering Bangladesh, in 2001 and 2007 respectively. Seventy-one cases with 50 deaths (70%) were reported in these two outbreaks3. Unlike the first NiV outbreak in which pigs were involved as intermediate hosts for disease transmission, the outbreaks in Bangladesh and India were associated with consumption of fruits or fruit products (such as raw date palm sap) contaminated with urine or saliva from infected fruit bats2. Raw date palm sap is harvested by shaving one side of the date palm tree in a V shape and then a small wooden pipe is placed at the base of the V to allow the sap to flow into a clay pot for collection over the night. Bats frequently visit the harvested date palm trees and lick the sap stream that flows from the shaved part of the tree to the collection pot4. They may shed the Nipah virus into the sap and transmit the disease to humans. There was also evidence of human-to-human transmission among family and care givers of infected patients as well as in healthcare settings. Nosocomial transmission accounted for around 75% of cases reported in the outbreak in India in 2001 and about half of the reported cases in Bangladesh from 2001 to 2008 were due to human-to-human transmission1.

Geographical distribution of NiV Outbreaks of NiV in Southeast Asia have a strong seasonal pattern, usually during winter and spring from December to May, and a limited geographical range. This could be related to the breeding season of the bats, increased shedding of virus by the bats and the date palm sap harvesting season5. Apart from the four countries with reported human NiV outbreaks (Bangladesh, India, Malaysia and Singapore), other countries in which Pteropus fruit bats live are at potential risk of NiV infection. The distribution of these bats extends from the east coast of Africa, across South and Southeast Asia, east to the Philippines, Pacific islands and Australia6,7. Nipah virus can emerge as a human pathogen anywhere in these distribution areas. Countries/areas with serological evidence or molecular detection in the natural reservoir (Pteropus bats species) and several

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other bat species include Bangladesh, Cambodia, Mainland China, Ghana, India, Indonesia, Madagascar, Papua New Guinea, the Philippines, Taiwan and Thailand.

The latest outbreak in India On May 19, 2018, a third outbreak of NiV infection was reported in the Southern State of Kerala in India (Figure 1)8. At the beginning, three deaths in the same family were reported in the Kozhikode District of Kerala. Field investigation revealed that there were bats living in an abandoned water well on the premises of a new house where the family had plans to move into Figure 1 - Affected areas in the third NiV outbreak in Kerala, India. after renovation. As of June 2, 2018, there were 19 reported cases (18 confirmed by laboratory tests) from two affected districts (Kozhikode and Malappuram) in Kerala State9. Seventeen of the 19 reported cases died. All the reported cases were found to have direct or indirect contact with the first casualty or the family prior to contracting the disease, including a health care worker.

In response to the outbreak, a multi-disciplinary team led by the Indian Government’s National Centre for Disease Control (NCDC) has been formed in Kerala and the World Health Organization (WHO) has also provided technical support to the Government of India as needed7. Contact tracing has been initiated. Infection prevention and control measures have been strengthened in health facilities. Relevant sectors including animal health, wildlife and environment sectors have been involved to establish the origin and spill-over of the disease from animal to human. Risk communication messages were being delivered to the community, public and stakeholders to increase their awareness of the disease. So far, the disease has not spread to new areas. The WHO considered that the outbreak was localised at the moment and the risk was low at the national and regional levels.

Prevention of NiV To reduce the risk of infection when travelling to places affected by NiV, the public should adopt the following measures: ✦ Avoid contact with farm animals or wild animals, especially bats and pigs; ✦ Observe good personal hygiene; wash hands frequently with liquid soap and water, especially after contact with animals or their droppings/secretions, and taking caring of or visiting sick people; and ✦ Observe good food hygiene; fruits should be thoroughly washed and peeled before consumption. Avoid drinking raw date palm sap.

In Hong Kong, no cases have been reported to the Centre for Health Protection (CHP) of the Department of Health so far. CHP will continue to closely monitor the situation, maintain close liaison with WHO and perform risk assessment based on the latest available information. Further information is available from the CHP’s website (https://www.chp.gov.hk/en/ healthtopics/content/24/100584.html).

Nipah virus (NiV) is an enveloped RNA virus of the family Paramyxoviridae, genus Henipavirus, and is closely related to Hendra virus. Fruit bats of the family Pteropodidae are the natural hosts for NiV. Transmission of the disease is mainly through direct contact with infected animal (usually bats and pigs) or their contaminated body fluids (respiratory droplets, throat or nasal secretions) or tissues. It can also be transmitted via the consumption of food products (e.g. raw date palm juice) contaminated with urine or saliva from infected fruit bats. Human-to-human transmission is also possible through close contact with infected persons’ secretions (especially respiratory) and excretions. The incubation period for NiV infection is around four to 14 days, but a period as long as 45 days has been reported. Clinical manifestations range from asymptomatic infection to acute respiratory infection (mild to severe) and fatal encephalitis. Infected people initially develop influenza-like symptoms of fever, , myalgia (muscle pain), vomiting and sore throat. This can be followed by dizziness, drowsiness, altered consciousness, and neurological signs that indicate acute encephalitis. Some cases may develop atypical pneumonia and severe respiratory problems, including acute respiratory distress. Most people who survive acute encephalitis make a full recovery, but long term neurologic conditions have been reported in survivors. Approximately 20% of patients are left with residual neurological consequences such as seizure disorder and personality changes. The case fatality rate is estimated to range from 40% to 75%. There are currently no drugs or vaccines specific for NiV infection. The primary treatment for human cases is intensive supportive care.

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References 1Nipah virus factsheet. World Health Organization (WHO). Available at http://www.who.int/news-room/fact-sheets/detail/nipah-virus. 2Factsheet: Nipah Virus (NiV). US Centers for Disease Control and Prevention (US CDC). Available at: https://www.cdc.gov/vhf/nipah/pdf/factsheet.pdf. 3WHO Morbidity and mortality due to Nipah or Nipah-like virus encephalitis in WHO South-East Asia Region, 2001-2018. Available at: http://www.searo.who.int/entity/emerging_diseases/links/morbidity-and-mortality-nipah-sear-2001-2018.pdf?ua=1. 4Nazmun N.; Repon C.P.; Rebeca S.; et al. Raw Sap Consumption Habits and Its Association with Knowledge of Nipah Virus in Two Endemic Districts in Bangladesh. PLoS One. 2015; 10(11): e0142292. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4638332/pdf/pone.0142292.pdf 5Nipah virus outbreaks in the WHO South-East Asia Region. World Health Organization (WHO). Available at: http://www.searo.who.int/entity/emerging_diseases/links/nipah_virus_outbreaks_sear/en/. 6Nipah virus distribution map. US Centers for Disease Control and Prevention (US CDC). Available at https://www.cdc.gov/vhf/nipah/outbreaks/distribution-map.html. 7Surveillance and outbreak alert, Nipah virus - FAQs World Health Organization (WHO). Available at: http://www.searo.who.int/entity/emerging_diseases/links/nipah_virus_faq/en/. 8Nipah virus - India. Disease Outbreak News. May 31, 2018. World Health Organization (WHO). Available at: http://www.who.int/csr/don/31-may-2018-nipah-virus-india/en/. 9India, Nipah virus infection updates. Ministry of Health and Family Welfare press release - June 2, 2018. World Health Organization (WHO). Available at: http://www.searo.who.int/india/topics/emergencies/ministry-of-health-and-family-welfare-press-release-2june2018.pdf.

Update on Global and Local Epidemiology of Meningococcal Disease Reported by Dr Cindy POON, Medical and Health Officer, Vaccine Preventable Disease Office, Surveillance and Epidemiology Branch, CHP.

Background1 Meningococcal disease refers to illness caused by Neisseria meningitidis bacteria. The disease was first described in 1805 when an outbreak swept Geneva, Switzerland, although the causative bacterium was only identified in 1887. Subsequently, major outbreaks were recorded during the two world wars and epidemics have been reported on the African continent since 1909.

Global epidemiology2,3,4 There have been epidemics of meningococcal disease in Asia, Europe and the Americas, but the largest and most frequently recurring outbreaks occurred in sub-Saharan Africa. Epidemics occur in seasonal cycles during the dry season from December to June in the African meningitis belt which stretches across the continent from Senegal to Ethiopia (Figure 1). Major epidemics occur every five to 12 years in this region, during which the attack rates can reach 1 000 cases per 100 000 persons in affected areas. Other regions of the world also have occasional outbreaks but significantly lower incidence of less than three cases per 100 000 population. Figure 1 - Meningitis belt and countries at high risk of meningococcal meningitis5. (Source from WHO)

According to the World Health Organization (WHO), there are no reliable estimates of global meningococcal disease burden due to inadequate surveillance in several parts of the world. Of the 12 N. meningitidis serogroups identified, serogroups A, B, C, X, W, a n d Y a re re s p o n s i b l e fo r t h e m a j o r i t y o f t h e d i s e a s e , b u t s e ro g ro u p d i s t r i b u t i o n v a r i e s by l o c a t i o n a n d t i m e . S e ro g ro u p A h a d historically accounted for 90% of meningococcal disease cases in the meningitis belt. After the progressive roll-out of monovalent serogroup A meningococcal conjugate vaccine in 2010, outbreaks due to serogroup A have been significantly reduced. Recent epidemics and outbreaks in the meningitis belt were primarily due to serogroups C, W and X. Dry and dusty conditions during the dry season between December and June, large population displacements at the regional level due to pilgrimages and overcrowded living conditions are risk factors for meningococcal disease outbreaks in the region. In the Americas, Australia and Europe, majority of cases were accounted by serogroups B, C and Y, though increasing numbers of serogroup W have been observed in some areas. In Asia, five major serogroups (A, B, C,W andY) were reported to be variedly present in different countries.

COMMUNICABLE DISEASES WATCH 52 Jun 3 - Jun 16 2018 WEEKS 23 - 24 VOL 15 ISSUE NO 12 Local epidemiology Invasive meningococcal infection is a statutory notifiable disease in Hong Kong. In the past five years, a total of 24 sporadic cases were recorded by the Centre for Health Protection (CHP) of the Department of Health (DH). Three to six cases were reported annually, giving an annual incidence of 0.04 – 0.08 per 100 000 population. The ages of the patients ranged from one month to 97 years (median: 50 years), with 15 (63 %) of them being male. Five (21%), 14 (58%) and five (21%) cases affected children aged below 18 years, adults aged 18-64 years and elderly aged 65 years or above respectively. Twenty cases (83%) had probably acquired the infection locally (Figure 2). Two cases were imported from Mainland China and one case was imported from the United Kingdom. Figure 2 - Annual number of cases of invasive The remaining patient worked in Hong Kong but lived in Mainland China, and meningococcal infection in Hong Kong by importation status, 2013-2018 (*as of June 20, 2018). thus the importation status was undetermined.

Invasive meningococcal infection mainly results in severe illness including meningitis and sepsis. Among the 24 cases, 13 cases were diagnosed as sepsis, six cases were diagnosed as meningitis, three cases had both forms of the disease and two cases were diagnosed as septic arthritis. The most common serogroup identified was serogroup Y (eight cases), followed by serogroup B (six cases), serogroup C (three cases), serogroup W135 (three cases) and serogroup X (one case). There were three cases with unknown serogroup. One fatal case was recorded each year in 2015, 2016 and 2017, giving an overall case fatality rate of 12.5%.

In 2018, seven sporadic confirmed cases of invasive meningococcal infection affecting six persons have been reported to the CHP (as of June 20), exceeding the annual number of cases in the past five years. Two cases were actually the same person having been infected by N. Meningitidis of different serogroups in two different episodes. He (22-year-old) had one episode of meningitis and sepsis in January 2018 caused by serogroup Y and another episode of sepsis caused by serogroup B in June 2018. He had no travel history during the incubation period in the first episode and was classified as locally acquired infection. He had travelled to Mainland China and Macao during the incubation period in the second episode. The other five cases affected one male and four females aged one month to 65 years. One of them had history of travel to the United Kingdom and the Czech Republic during the whole incubation period and was classified as imported infection. The cases were either diagnosed as sepsis (four cases) or having both meningitis and sepsis (one case). Serogroup C was identified in two cases, while serogroups B,Y and W135 were each identified in one case. One fatal case was recorded in June with the cause of death currently under investigation. No neurological sequelae were recorded among those recovered.

Preventive measures Meningococcal infection is mainly transmitted by direct person-to-person contact and through respiratory droplets from patients or asymptomatic meningococcal carriers. Therefore, members of the public are advised to observe good personal and environmental hygiene practices to avoid the infection.

While sporadic cases of meningococcal disease are known to occur in some countries in schools, colleges, military barracks and other places where large numbers of adolescents and young adults congregate, the risk of contracting meningococcal disease in travellers is generally low. Nonetheless, persons who are planning their trip to Mecca in Saudi Arabia during the Hajj pilgrimage, to sub-Saharan regions of mid Africa during the dry season, or to areas that are known to experience epidemic meningococcal disease should seek professional advice from doctors for vaccination in view of the individual’s age, health condition, and details of the journey such as place, duration and nature. The public can refer to DH’s Travel Health Service website(https:// www.travelhealth.gov.hk/english/travel_related_diseases/news.html#Meningococcal_meningitis) or announcements of other health authorities (e.g. WHO and Centers for Disease Control and Prevention of the United States) for information on areas/ places with epidemic meningococcal disease.

References 1World Health Organization. Impact of the problem - Meningococcal disease. Available at http://www.who.int/csr/disease/meningococcal/impact/en/, accessed on June 20, 2018. 2World Health Organization. International travel and health. Meningococcal disease. Available at: http://www.who.int/ith/diseases/meningococcal/en/, accessed on June 20, 2018. 3Centers for Disease Control and Prevention. Meningococcal disease. Available at: https://www.cdc.gov/meningococcal/index.html, accessed on June 20, 2018. 4Borrow, R.;Alarcon, P.; Carlos, J.; et al. The Global Meningococcal Initiative: Global epidemiology, the impact of vaccines on meningococcal disease and the importance of herd protection. Expert. Rev.Vaccines 2017, 16, 313-328. 5World Health Organization. Meningococcal meningitis, countries or areas at high risk, 2014. Available at: http://gamapserver.who.int/mapLibrary/Files/Maps/Global_MeningitisRisk_ITHRiskMap.png?ua=1&ua=1&ua=1, accessed on June 20, 2018.

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Two sporadic cases of listeriosis

The Centre for Health Protection (CHP) recorded two cases of listeriosis in early June 2018. The first case was an 89-year- old woman with underlying illness. She developed fever and vomiting on June 1 and was admitted to a public hospital on June 2. Her blood culture collected on June 2 yielded Listeria monocytogenes. She was treated with antibiotics and her condition was stable. She did not recall consuming any high-risk food during the incubation period.

The second case was a 60-year-old man with underlying illness. He was admitted to a public hospital for acute heart failure on June 1. His blood culture collected on June 1 yielded Listeria monocytogenes. The clinical diagnoses were heart failure and sepsis. He was treated with antibiotics and required intensive care. He developed cardiogenic shock with multi-organ failure and he passed away on June 4. According to his family, he had consumed a variety of ready-to-eat foods, including , salad and sushi during the incubation period.

Both patients had no travel history during the incubation period and their household contacts remained asymptomatic. So far, no epidemiological linkage has been identified among the two cases.

A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection

On June 4, 2018, CHP recorded a sporadic case of necrotising fasciitis due to Vibrio vulnificus infection affecting a 63-year-old male with good past health. He presented with fever and bilateral painful upper limbs swelling on June 3. He was admitted to a public hospital on June 3 and was treated with antibiotics and surgical debridement. The clinical diagnosis was necrotising fasciitis and his condition was stable. Right upper limb tissue collected on June 3 grew Vibrio vulnificus. He had history of catching fishes in an abandoned pond but did not report injury. He had no recent travel history and his home contacts were asymptomatic.

A sporadic case of Streptococcus suis infection

On June 5, 2018, CHP recorded a sporadic case of Streptococcus suis infection affecting a 47-year-old woman with good past health. She had presented with fever, headache and dizziness since June 2. She had an episode of loss of consciousness on June 3 and was admitted to a public hospital on the same day. Her blood collected on June 3 grew Streptococcus suis. She was treated with antibiotics and her condition remained stable. She had a small cut by metal on her right hand and had handled raw pork at home during incubation period. Her home contacts remained asymptomatic.

Infectious Disease (ID) Forum “Human Papilloma Virus (HPV) - Next Steps” on June 11, 2018

On June 11, 2018, an ID Forum with the title “Human Papilloma Virus - Next Steps” was held. Professor Richard Hillman from St Vincent’s Hospital Australia, gave an international perspective on the topic highlighting that HPV as an infective agent as well as a major oncogen. He exemplified how Hong Kong’s HPV-related problem was progressively expanding by using local cancer data. He also shared Australia’s experiences on primary prevention and secondary prevention via vaccination and screening . Australia is now moving towards gender neutral vaccination.

Dr KM HO, Consultant-in-Charge, Social Hygiene Service, Public Health Service Branch, CHP gave a talk on HPV vaccination in Hong Kong. It was interesting to note that the public was now becoming aware of the benefits of HPV vaccination. Started in 2016, the Photo of the two speakers and the moderator taken after the Community Care Fund piloted for three years a free HPV vaccination Infectious Disease Forum: Human Papilloma Virus – Next Steps. scheme for targeted recipients. The fruitful local experience coupled with overseas recommendations would serve to inform application of HPV vaccine for cervical cancer prevention in Hong Kong.

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CA-MRSA cases in May 2018

In May 2018, CHP recorded a total of 125 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 79 males and 46 females with ages ranging from seven months to 100 years (median: 33 years). Among them, there were 92 Chinese, 8 Filipinos, 6 Indian, 6 Pakistani, 5 Caucasian, 2 Malaysian, 1 African, 1 Japanese, and 4 of unknown ethnicity.

One hundred and twenty-three cases presented with uncomplicated skin and soft tissue infections while the remaining two cases had severe CA-MRSA infections. The first severe case affected a 44-year-old man who presented with fever, right facial swelling and lip blisters since April 24. He was admitted to a public hospital on April 26. His blood specimen collected on the same day was cultured positive for CA-MRSA. His clinical diagnosis was right facial cellulitis complicated with sepsis and he was treated with antibiotics. He remained stable and was discharged on May 21. The second severe case affected a 100-year- old woman with underlying illnesses. She had a pressure sore over right ankle since February. She developed fever and worsening of right ankle wound infection on May 12, and was admitted to a public hospital on the same day. X-ray of her right foot showed signs of osteomyelitis.Wound swab collected from her right ankle on May 13 was cultured positive for CA-MRSA. She was diagnosed with right foot ulcer complicated with osteomyelitis. She was treated with antibiotics and remained in a stable condition.

Among the 125 cases, one was a nurse working in a public hospital. Investigation did not reveal any epidemiologically linked cases. Besides, five clusters, with each affecting two to three persons, were identified in May. Four clusters occurred in households while the remaining one occurred in a student dormitory.

Scarlet fever update (May 1, 2018 – May 31, 2018)

Scarlet fever activity in May increased as compared with that in April. CHP recorded 168 cases of scarlet fever in May as compared with 124 cases in April.The cases recorded in May included 105 males and 63 females aged between seven months and 35 years (median: five years).There were three institutional clusters occurring in two kindergartens and a primary school, affecting a total of eight children. No fatal cases were reported in May.

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EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Review on non-typhoidal Salmonella food poisoning in Hong Kong, 2013-2018 Reported by Dr Zenith WU, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Salmonella is a Gram-negative bacteria belonging to the Enterobacteriaceae family. To date, more than 2 500 Salmonella serotypes have been identified1. Salmonella is commonly found in the intestines of animals (especially poultry) and eggs. The common sources of food poisoning caused by Salmonella include egg, poultry, beef and pork. Non-typhoidal Salmonella refers to all serotypes of Salmonella except Typhi, Paratyphi A, Paratyphi B (excluding variant Java) and Paratyphi C*. Being a leading cause of bacterial diarrhoea worldwide, non-typhoidal Salmonella is estimated to cause approximately 153 million cases of gastroenteritis and 57 000 deaths globally each year2. The disease is usually acquired through consumption of contaminated food of animal origin (mainly egg, poultry, beef and pork) but transmission can also occur through direct contact with infected animals or their environment and directly between humans2. The incubation period of non-typhoidal Salmonella infection ranges from six to 72 hours (usually from 12 to 36 hours) and the illness usually lasts from two to seven days. Common symptoms include abdominal pain, diarrhoea, nausea, vomiting and fever. The illness is usually self-limiting and most patients recover without specific treatment. However, in some cases, particularly in children and the elderly, severe and life-threatening complications may occur1.

*Salmonella infection caused by Salmonella Typhi or Salmonella Paratyphi are referred to as typhoid fever and paratyphoid fever respectively.

Food poisoning is a notifiable disease in Hong Kong. It is caused by consumption of contaminated food or drink containing bacteria, viruses or toxins of biochemical or chemical nature. In this article, we reviewed the local epidemiology of food poisoning caused by non-typhoidal Salmonella from 2013 to 2018 (as of March 31), which was the commonest bacterial pathogen among confirmed food poisoning cases in Hong Kong.

From 2013 to 2018 (as of March 31), the Centre for Health Protection (CHP) of the Department of Health recorded a total of 1 256 food poisoning cases affecting a total of 5 582 persons. Among these 1 256 cases, 397 (31.6%) were confirmed, with the majority caused by bacteria (271 cases, 68.3%). Non-typhoidal Salmonella accounted for the majority (185 cases, 68.3%) of the confirmed bacterial food poisoning cases, followed by Vibrio parahaemolyticus (75 cases, 27.7%) and other bacteria (11 cases, 4.1%).

From 2013 to 2017, the annual number of confirmed non-typhoidal Salmonella food poisoning cases ranged from 11 to 59, with the number of persons affected ranging from 54 to 259 (Figure 1). In the first three months of 2018, ten confirmed non-typhoidal Salmonella food poisoning cases have been recorded, affecting 29 persons. The large number of confirmed non-typhoidal Salmonella food poisoning cases recorded in 2015 was due to a cluster of 34 food poisoning cases related to the consumption of the same brand of sandwiches imported from Taiwan.

The number of persons affected in each case ranged from two to 62 (median: three persons per case). The majority (159, 85.9%) of the cases affected five persons or below and only five cases (2.7%) affected more than 20 persons. Among the 849 affected persons, Figure 1 - Number of confirmed non-typhoidal Salmonella food 43.5% were male and 56.5% were female. Their ages ranged from poisoning cases and persons affected in Hong Kong, 2013-2018 one to 85 years. A total of 138 affected persons (16.2%) required (*as of March 31). hospitalisation and no fatal case was recorded.

COMMUNICABLE DISEASES WATCH 56 Jun 17 - Jun 30 2018 WEEKS 25 - 26 VOL 15 ISSUE NO 13 In the 69 cases with a single incriminating food item and ingredient identified, the commonest incriminating ingredients were egg (72.5%), chicken (11.6%) and other meats such as beef and pork (10.1%). Among the contributing factors, inadequate cooking and contaminated raw food were commonly implicated.

To prevent foodborne diseases, the “Five Keys to Food Safety”, advocated by the World Health Organization, are five simple and effective keys for people to follow when handling food3. The core messages of the Five Keys to Food Safety are:

1. Choose (Choose safe raw materials); 2. Clean (Keep hands and utensils clean); 3. Separate (Separate raw and cooked food); 4. Cook (Cook thoroughly); and 5. Safe Temperature (Keep food at safe temperature).

In particular, to prevent food poisoning due to non-typhoidal Salmonella, members of the public are reminded to cook high risk foods such as egg, poultry, beef and pork thoroughly, and avoid using raw unpasteurised eggs in preparing dishes that would not be subject to heat treatment.

References 1World Health Organization. Salmonella (non-typhoidal). Available at http://www.who.int/news-room/fact-sheets/detail/salmonella-(non-typhoidal), accessed on June 28, 2018. 2Centers for Disease Control and Prevention. Salmonella (non-typhoidal). Available at: https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/-nontyphoidal, accessed on June 28, 2018. 3Centre for Food Safety. 5 Keys to Food Safety. Available at: http://www.cfs.gov.hk/english/consumer_zone/consumer_zone_5_Keys_to_Food_Safety.html, accessed on June 28, 2018.

Exercise "Sunstone" tests government response to novel disease Reported by Emergency Response and Information Branch, CHP.

The Centre for Health Protection (CHP) of the Department of Health (DH), in collaboration with other government departments and organisations, tested the Government's response to a novel disease called "Disease X" at a newly built residential building on June 27, 2018 during a public health exercise code- named "Sunstone".

The exercise was aimed at assessing the interoperability of government departments and relevant organisations in response to the detection of a novel disease, testing their preparedness to respond effectively to a major infectious disease outbreak, as well as validating the interdepartmental procedures and Exercise “Sunstone” government contingency actions on the ensuing isolation and evacuation of a Photo 1 - Director of Health, Dr Constance CHAN residential building. (3rd right), was inspecting the exercise at a newly built residential building. The exercise consisted of two parts. The first part was a table-top exercise conducted on May 24, 2018, in which relevant departments and organisations discussed and co-ordinated the communicable disease response measures required in the simulated scenario of detection of a number of cases of "Disease X" in Hong Kong. According to the World Health Organization, "Disease X" represents the knowledge that a communicable disease could be caused by a pathogen currently unknown to cause human disease.

The second part was a ground movement exercise conducted on June 27, 2018. Under the exercise simulation, CHP received the Hospital Authority's report on four suspected cases of "Disease X" who resided in the same residential building. Among them, one patient passed away shortly after Exercise “Sunstone” admission to the hospital while the remaining three required hospitalisation. Photo 2 - A resident suspected to have been infected with the novel disease was being taken to hospital.

COMMUNICABLE DISEASES WATCH 57 Jun 17 - Jun 30 2018 WEEKS 25 - 26 VOL 15 ISSUE NO 13 DH immediately co-ordinated with relevant government departments and organisations to formulate and implement corresponding measures, and activated the Multi-disciplinary Response Team to conduct investigation and examination of the environmental factors suspected to have contributed to the spread of this disease. Upon comprehension of the investigation findings, CHP advised the Director of Health to order the isolation of the affected building and evacuate the residents.The symptomatic residents were conveyed to hospital for isolation whereas those asymptomatic were sent to quarantine Exercise “Sunstone” centres. Disinfection was carried out subsequently at the affected building, which would remain isolated until DH confirms that it is safe for lifting the Photo 3 - Officers from the Drainage Services isolation order. Department were inspecting the sewage system outside the building. About 150 participants from relevant government departments and organisations took part in the exercise, including 28 experts from the Mainland and Macao health authorities as observers. The exercise provided a valuable platform to test the preparedness of relevant government departments and organisations to respond effectively to a major infectious disease outbreak. It also enhanced the effectiveness of the response plans for communicable disease and the preparedness of relevant stakeholders in the control and prevention of communicable diseases. Exercise “Sunstone”

Photo 4 - Representatives from various government departments and organisations were being briefed on the situation and necessary actions at the field command post set up at scene.

NEWS IN BRIEF

A sporadic case of Listeriosis

On June 19, 2018, the Centre for Health Protection (CHP) recorded a case of listeriosis affecting an 83-year-old woman with underlying illnesses. She presented with fever on June 13 and was admitted to a public hospital on June 14. Her blood culture collected on June 14 yielded Listeria monocytogenes.The clinical diagnosis was sepsis and she was treated with antibiotics. Her condition later deteriorated and complicated with pneumonia. She passed away on July 2. She had no recent travel history and did not consume any high-risk food during the incubation period. Her home contacts were asymptomatic.

A sporadic case of Streptococcus suis infection

On June 19, 2018, CHP recorded a case of Streptococcus suis infection affecting a 49-year-old man with underlying illnesses. He presented with fever and left index finger swelling on June 16, and was admitted to a private hospital on the same day. His blood sample collected on June 16 cultured Streptococcus suis. His clinical diagnoses were left index finger cellulitis and sepsis. He was treated with antibiotics and his condition was stable. He was discharged on June 23. He had no travel history during the incubation period. He had handled raw pork with bare hands at home two days before symptoms onset but he could not recall any previous skin wound. His home contacts were asymptomatic.

A sporadic case of necrotising fasciitis caused by Vibrio vulnificus

On June 25, 2018, CHP recorded a case of necrotising fasciitis due to Vibrio vulnificus affecting an 82-year-old man with underlying illnesses. He presented with right lower limb pain, swelling and redness on June 22 and was admitted to a public hospital on the same day. Surgical debridement was performed on June 23 and right lower limb tissue specimen collected on the same day yielded Vibrio vulnificus. The clinical diagnosis was necrotising fasciitis. He was transferred to the intensive care unit for further management after the surgery and his condition subsequently stablised. He had travelled alone to Guangdong from June 15 to 19. He had a small wound on his right shin since June 15 but he could not recall the details of the injury. He also went swimming at a local beach after he returned to Hong Kong. His home contacts were asymptomatic.

COMMUNICABLE DISEASES WATCH 58 Jul 1 - Jul 14 2018 WEEKS 27 - 28 VOL 15 ISSUE NO 14

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Review of Human Metapneumovirus Infection in Hong Kong Reported by Dr Ashley FONG, Medical and Health Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP.

Human metapneumovirus (HMPV) is a single stranded RNA virus that belongs to the Paramyxoviridae family. It can cause upper and lower respiratory infections in people of all ages, especially young children, elderly and immunocompromised people. HMPV has been reported worldwide since it was first reported in 2001.

The clinical presentations of HMPV are similar to other viruses that cause upper and lower respiratory infections. In children, HMPV causes symptoms such as fever, cough, nasal congestion, difficulty in breathing or shortness of breath. Some children may also present with otitis media, diarrhoea, vomiting, rash, and febrile convulsion. In adults, HMPV usually causes mild disease characterised by cough, hoarseness, runny nose and sputum production. HMPV infection may progress to bronchiolitis or pneumonia.

We reviewed the institutional outbreaks caused by HMPV recorded by the Centre for Health Protection (CHP) of the Department of Health from 2013 to June 2018.

CHP recorded a total of 69 institutional outbreaks related to HMPV from 2013 to June 2018, including two outbreaks with both HMPV and other respiratory pathogens identified. There were six to ten outbreaks each year from 2013 to 2017. In 2018 (as of June 2018), 24 outbreaks have been recorded (Figure 1). Relatively more outbreaks occurred from March to May in the past five years (Figure 2). Among the 69 outbreaks, 29 outbreaks (42%) occurred in residential care homes for the elderly, 16 (23%) in hospitals, 9 (13%) in kindergartens/ child care centres, 2 (3%) in primary schools and 13 (19%) in other institutions.

The duration of the outbreaks, which was defined as the interval between the onset dates of the first and last cases of an outbreak, Figure 1 – Annual Number of HMPV Institutional Outbreaks, 2013 to June 2018. ranged from one to 37 days (median: ten days). The number of persons affected in each outbreak ranged from three to 42 (median: seven). The attack rate ranged from 1% to 51% (median: 10%). Among the 689 affected persons, 313 (45%) required hospitalisation, 123 (18%) developed complications and two (0.3%) died of pneumonia.

HMPV can be transmitted by direct or indirect contact. It is most likely spread from an infected person to others through: secretions from coughing and sneezing, close personal contact, such as touching or shaking hands, and touching the mouth, nose or eyes after touching contaminated articles. There is no specific treatment for HMPV infection. Figure 2 – Monthly Number of HMPV Institutional Outbreaks caused by HMPV, 2013 to 2017.

COMMUNICABLE DISEASES WATCH 59 Jul 1 - Jul 14 2018 WEEKS 27 - 28 VOL 15 ISSUE NO 14 To p r e v e n t H M P V i n f e c t i o n , m e m b e r s o f t h e p u b l i c a r e a d v i s e d t o : Maintain good personal hygiene ✦ Perform hand hygiene frequently, especially before touching the mouth, nose or eyes, after touching public installations such as handrails or door knobs or when hands are contaminated by respiratory secretion after coughing or sneezing. Wash hands with liquid soap and water for at least 20 seconds, then dry with a disposable paper towel or hand dryer.When hands are not visibly soiled, clean them with 70 to 80% alcohol-based handrub as an effective alternative; ✦ Cover nose and mouth with tissue paper when sneezing or coughing. Dispose the soiled tissues into a lidded rubbish bin, then wash hands thoroughly; ✦ Avoid sharing cups and eating utensils with others; ✦ When having respiratory symptoms, wear a surgical mask, avoid going to crowded places and seek medical advice promptly; and ✦ Exclude infected persons from providing care to children, elderly and immunocompromised people.

Maintain good environmental hygiene ✦ Regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing one part of 5.25% bleach with 99 parts of water), leave for 15 to 30 minutes, and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol; ✦ Use absorbent disposable towels to wipe away obvious contaminants such as respiratory secretions, and then disinfect the surface and neighbouring areas with 1:49 diluted household bleach (mixing one part of 5.25% bleach with 49 parts of water), leave for 15 to 30 minutes and then rinse with water and keep dry. For metallic surface, disinfect with 70% alcohol; and ✦ Maintain good indoor ventilation.Avoid going to crowded or poorly ventilated public places.

Update on Diphtheria in Hong Kong Reported by Dr CHAN Hong-lam, Medical and Health Officer, Vaccine Preventable Disease Office, and Dr YH LEUNG, Senior Medical and Health Officer, Communicable Disease Division, Surveillance and Epidemiology Branch, CHP.

Diphtheria is an acute infectious disease caused by the bacterium Corynbacterium diphtheriae. It affects mainly the respiratory tract, causing respiratory diphtheria. Persons with respiratory diphtheria usually present with fever, sore throat with patches of greyish membrane adhered to the throat, and breathing difficulty. In serious cases, it can cause airway obstruction, heart failure and nerve damage. Fatal cases can occur. Occasionally the bacterium can affect skin, causing cutaneous diphtheria. C. diphtheriae can replicate on the surface of mucous membrane. Aural, vaginal, conjunctival and cutaneous diphtheria account for approximately 2% of diphtheria cases1.

Morbidity and mortality of the infections are mainly due to diphtheria toxin produced by the bacterium. Exotoxin produced by the bacterium can be absorbed from skin lesions, and causes toxic damage to organs such as heart, kidneys and nervous system2. Diphtheria is mainly transmitted by coming into contact with droplets from the respiratory tract of an infected person (e.g. from coughing or sneezing), and less commonly through physical contact with the wounds or skin lesions of an infected person.

Global epidemiology and re-emergence According to the latest information from World Health Organization (WHO)3, reported diphtheria cases globally declined from almost 10 000 cases per year during 2000-2004 to 5 288 per year during 2005-2009 and leveled off since then4. South-East Asia region, particularly India, accounted for the majority of global diphtheria burden in recent years. India reported 18 350 cases in 2011-2015, followed by Indonesia which reported 3 203 cases. Some other Asian countries including Nepal (1 440 cases), Lao People’s Democratic Republic (344 cases), Pakistan (321 cases), Myanmar (180 cases) and Thailand (157 cases) were also among countries reporting most cases of diphtheria in 2011-2015 worldwide.

Although cases of diphtheria are rarely reported in developed countries, people who have not received immunisation with diphtheria toxoid are susceptible to the disease. For instance, in Singapore, a 21-year-old foreign worker from Bangladesh presented to a hospital in August 2017 with fever, sore throat and neck swelling5. His respiratory sample tested positive for toxigenic C. diphtheriae. The patient passed away five days after symptoms onset. He did not have recent travel history out of Singapore before his onset, and hence he was likely infected in Singapore. According to the Ministry of Health of Singapore, prior to this case, the last local and imported cases of diphtheria had been recorded in 1992 and 1996 respectively. The occurrence of this recent case in Singapore highlighted the potential of re-emergence of diphtheria and importance of immunisation and continuous surveillance.

Although cutaneous diphtheria occurs rarely and data are not routinely reported in many surveillance systems (for example the Joint Reporting Form of WHO)6, cases of cutaneous diphtheria have been reported in Australia7 (two cases in 2014) and New Zealand8 (one to two cases annually in 2014-2016) in recent years. Most of the cases had travel history to Asia or South Pacific region during the incubation period.

COMMUNICABLE DISEASES WATCH 60 Jul 1 - Jul 14 2018 WEEKS 27 - 28 VOL 15 ISSUE NO 14 Local immunisation In Hong Kong, diphtheria-containing vaccine was first introduced in 1956 with diphtheria, tetanus & whole cell pertussis vaccine (DTwP) given to children at 2-4 months, 3-5 months, 4-6 months and 18 months of age, and diphtheria and tetanus (DT) vaccine given at Primary one. Currently, the Hong Kong Childhood Immunisation Programme provides free diphtheria, tetanus, acellular pertussis and inactivated poliovirus (DTaP-IPV) vaccines to eligible children at two, four and six months of age, followed by booster doses at 18 months, Primary one and Primary six (reduced dose).

Local epidemiology The annual number of reported diphtheria cases fell drastically since the early 1960s from nearly 1 500 cases per year to no more than two cases per year after 1972 (Figure 1). No respiratory diphtheria cases were recorded locally since the last fatal case occurring in 1982.

In April 2018, a sporadic case of cutaneous diphtheria affecting an 8 1 -ye a r- o l d H o n g Ko n g b o r n Chinese man with underlying illnesses was reported to the Centre for Health Protection (CHP) of the Department of Health. This is Figure 1 - Annual number of reported respiratory diphtheria cases, 1946-2017. the first case of cutaneous diphtheria with isolation of toxigenic C. diphtheriae recorded by CHP in the past 10 years. The patient had presented with a spontaneous left ankle swelling with wound and discharge since March 24, 2018. He was admitted to a public hospital on March 31 and physical examination showed two wounds over his left anterolateral and posterolateral ankle respectively. The clinical diagnosis was left leg cellulitis. He was given a course of antibiotics and was discharged on April 3.

Subsequently, his left anterior ankle wound swab collected on March 31 yielded toxigenic C. diphtheriae, and Staphylococcus aureus. He did not have fever or any respiratory symptoms all along and his clinical diagnosis was cutaneous diphtheria. He was called back by the hospital to complete a two-week course of antibiotics. Wound swab collected from the patient’s left ankle on April 18 was cultured negative and his left ankle wounds were found to have healed upon follow-up on May 15.

Epidemiological investigation revealed that the patient lived with his wife who had underlying illnesses. She also presented with a painful left ankle swelling on February 9 while she did not have fever, wound or respiratory symptoms. She was admitted to the same public hospital from February 12 to 13 with a clinical diagnosis of swollen ankle. No clinical specimen was collected from her and she was treated with a course of antibiotics with uneventful recovery.

The couple had travelled to the Philippines for four days in mid-September 2017 to meet their relatives. Their relatives were asymptomatic and the couple denied any contact history of patients with diphtheria or wound there. The couple’s vaccination history for diphtheria was unknown. Health advice on transmission, prevention and control of diphtheria was given to the couple and the patient’s wife declined chemoprophylaxis offered by CHP.

References 1World Health Organization. Diphtheria vaccine:WHO position paper - August 2017. Available at: http://apps.who.int/iris/bitstream/handle/10665/258681/WER9231.pdf;jsessionid=68095DA3943DD89DFE754B3A66824114?sequence=1, accessed on July 17, 2018. 2World Health Organization. Diphtheria vaccine - WHO position paper (January 2006). Available at: http://www.who.int/wer/2006/wer8103/en/, accessed on July 17, 2018. 3World Health Organization. Meeting of the Strategic Advisory Group of Experts on immunization,April 2017 - conclusions and recommendations. Available at: http://apps.who.int/iris/bitstream/handle/10665/255611/WER9222.pdf?sequence=1, accessed on July 17, 2018. 4World Health Organization. Review of Epidemiology of Diphtheria - 2000-2016. Available at: http://www.who.int/immunization/sage/meetings/2017/april/1_Final_report_Clarke_april3.pdf?ua=1,&ua=1, accessed on July 17, 2018. 5Singapore Ministry of Health. Confirmed case of Diphtheria in Singapore.Available at: https://www.moh.gov.sg/content/moh_web/home/pressRoom/pressRoomItemRelease/2017/confirmed-case-of-diphtheria-in-singapore.html, accessed on July 17, 2018. 6World Health Organization.WHO - recommended surveillance standard of diphtheria. Available at: http://www.who.int/immunization/monitoring_surveillance/burden/vpd/surveillance_type/passive/diphtheria_standards/en/, accessed on July 17, 2018. 7Australian Government The Department of Health. National notifiable diseases:Australia's notifiable diseases status:Annual report of the National Notifiable Diseases Surveillance System. Available at: http://www.health.gov.au/internet/main/Publishing.nsf/Content/cda-pubs-annlrpt-nndssar.htm, accessed on July 17, 2018. 8New Zealand Ministry of Health.Annual Surveillance Summary. Available at: https://surv.esr.cri.nz/surveillance/annual_surveillance.php, accessed on July 17, 2018. COMMUNICABLE DISEASES WATCH 61 Jul 1 - Jul 14 2018 WEEKS 27 - 28 VOL 15 ISSUE NO 14 NEWS IN BRIEF

An imported confirmed case of brucellosis On June 30, 2018, the Centre for Health Protection (CHP) recorded a confirmed case of brucellosis affecting a 52-year-old woman with underlying illnesses. The patient lives in Fujian with her husband and she used to be a butcher before mid-February 2018. She had history of neuro-brucellosis diagnosed in Fujian in 2014 and had received antibiotics. She presented with left knee swelling in July 2017. She attended a hospital in Fujian and was told that the swelling was one of the manifestations of her underlying illness.While the left knee swelling persisted, she then developed right thumb swelling on June 12, 2018. She came to Hong Kong on June 17 and was admitted to a public hospital on June 19. Aspiration of her left knee joint and right thumb swelling was done and she was discharged on June 22. Aspirate specimens of both sites yielded Brucella melitensis and she was called back for admission on June 29. She was treated with antibiotics and her condition was stable. She had history of slaughtering goat and handled goat internal organs when she worked as a butcher. Her home contact was asymptomatic.

A sporadic case of psittacosis On July 5, 2018, CHP recorded a case of psittacosis affecting a 36-year-old male with good past health. He had presented with fever, cough with sputum and runny nose since June 29 and was admitted to a public hospital on July 2. His chest X-ray showed left lower zone haziness. The clinical diagnosis was pneumonia. His sputum taken on July 3 was tested positive for psittaci DNA by polymerase chain reaction (PCR). He was treated with antibiotics and was discharged on July 7. He had no recent travel history and no history of direct contact with birds, bird droppings or bird carcasses during the incubation period. He lived with his wife and son. His wife remained asymptomatic whereas his son had fever and cough since July 4. His son sought medical attention from a general practitioner. He was diagnosed to have upper respiratory tract infection and had recovered.

A local sporadic case of listeriosis On July 10, 2018, CHP recorded a case of listeriosis affecting a 56-year-old man with underlying illness. He was admitted to a public hospital for management of his underlying illness on July 3. He developed fever on July 5 and his blood culture collected on July 7 yielded Listeria monocytogenes. He was treated with antibiotics and his condition was stable. The patient had no history of high risk food consumption during the incubation period. He lived with his wife who was asymptomatic.

A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection On July 13 2018, CHP recorded a sporadic case of necrotising fasciitis due to Vibrio vulnificus infection affecting a 44-year-old male with pre-existing medical conditions. He presented with chills and rigors, left foot painful swelling with redness and pus discharge on July 9. He was admitted to a public hospital on July 10. The clinical diagnosis was necrotising fasciitis. He was treated with antibiotics and surgical debridement. Left foot wound swab collected on July 11 was tested positive for Vibrio vulnificus. He had cut injury over left foot while walking on shallow water of a beach on July 2. He had no recent travel history and his home contacts were asymptomatic.

CA-MRSA cases in June 2018 In June 2018, CHP recorded a total of 109 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 70 males and 39 females with ages ranging from three months to 78 years (median: 35 years).Among them, there were 79 Chinese, 12 Filipinos, 3 Caucasian, 3 Pakistani, 2 Indian, 2 Nepalese and 8 of unknown ethnicity.

One hundred and eight cases presented with uncomplicated skin and soft tissue infections while the remaining case had severe CA-MRSA infection.The severe case affected a 61-year-old man who presented with fever and left calf pain since April 20. He sought medical advice from general practitioner but symptoms persisted. He attended the Accident and Emergency Department of a public hospital on May 6 and was admitted for management on the same day. Ultrasonography of his left leg suggested the presence of an abscess. He was treated with antibiotics, incision and drainage of his left leg abscess and excisional debridement of his left leg. Pus from his left leg abscess collected on May 19 and necrotic tissues of his left leg collected on June 1 were cultured positive for CA-MRSA. The clinical diagnosis was left leg intramuscular abscess. He remained in a stable condition and was discharged on June 21.

Among the 109 cases, one was a radiographer working in a private clinic. Investigation did not reveal any epidemiologically linked cases. Besides, five clusters, with each affecting two persons, were identified in June.

Scarlet fever update (June 1, 2018 – June 30, 2018) Scarlet fever activity continued to increase in June. CHP recorded 196 cases of scarlet fever in June as compared to 124 cases in April and 167 cases in May.The cases recorded in June included 121 males and 75 females aged between 10 months and 37 years (median: five years). There were seven institutional clusters occurring in kindergartens or child care centres, affecting a total of 21 children. No fatal cases were reported in June.

COMMUNICABLE DISEASES WATCH 62 Jul 15 - Jul 28 2018 WEEKS 29 - 30 VOL 15 ISSUE NO 15

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Review on Dengue Fever in Hong Kong, 2008-2018 Reported by Dr Zenith WU, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Facts on dengue fever Dengue fever (DF) is caused by the dengue virus which comprises four serotypes (type 1 to type 4). It is transmitted to humans through the bites of female Aedes mosquitoes. In Hong Kong, the principal vector Aedes aegypti is not found but the mosquito Aedes albopictus, which can also spread the disease, is commonly found. After a vector mosquito bites a patient suffering from DF, it may spread the disease by biting other people. Some infected people may not develop apparent symptoms or may only have mild symptoms like fever. Those who develop symptoms may have high fever, severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting, swollen lymph nodes and rash. The symptoms of first infection with one serotype are usually mild but subsequent infections with other serotypes of dengue virus are more likely to result in severe dengue (also known as “dengue haemorrhagic fever”), a severe and potentially fatal complication of DF. Currently there is no specific treatment for DF or severe dengue. DF is mostly self-limiting and symptomatic treatment could be offered to relieve discomfort, whereas patients with severe dengue should be treated promptly with supportive management. At present, there is no locally registered dengue vaccine available in Hong Kong.

DF is one of the most important vector-borne diseases in Hong Kong. DF is found in tropical and sub-tropical regions around the world.According to the World Health Organization, the incidence of DF has grown dramatically around the world in recent decades and about half of the world’s population is now at risk of DF1. It is now endemic in more than 100 countries in Africa, the Americas, the Eastern Mediterranean, South-east Asia and the Western Pacific.

In Hong Kong, DF is a notifiable disease since March 1994.All registered medical practitioners are required to notify the Centre for Health Protection (CHP) of the Department of Health of all suspected or confirmed cases of DF.

From 2008 to 2018 (as of July 26), CHP recorded a total of 857 DF cases. From 2008 to 2017, the annual number of cases ranged from 30 to 124 (Figure 1). In 2018, 51 cases have been recorded as of July 26.The number of cases recorded from 2013 to 2017 was 555, which accounted for 68.9% of the total number of cases in the past 10 years.

The 857 cases involved 471 males and 386 females, with ages ranging from three to 84 years (median: 37 years).Among the patients, fever was the most common symptom (828, 96.6%), followed by headache (523, 61%) and rash (451, 52.6%). Other common symptoms included myalgia (441, 51.5%), arthralgia (219, 25.6%) and eye pain (184, 21.5%). Six hundred and fifty one patients (76%) required hospitalisation and the length of stay ranged from one to 16 days (median: five days). Eight of them had severe dengue. No fatal case was recorded. Figure 1 – Annual number of DF cases from 2008 to 2018 (*figures as of July 26). Most of the cases (841, 98.1%) were imported from other countries/areas. For the 789 imported cases with the place of infection determined, the five countries that the patients had most commonly travelled to during the incubation period were Thailand (175), Indonesia (170), the Philippines (140), India (57) and Malaysia (52). For the remaining 52 imported cases, the patients had travelled to multiple countries during the incubation period. Local cases were recorded in 2010 (four cases), 2014 (three cases), 2015 (three cases), 2016 (four cases) and 2017 (one case).

COMMUNICABLE DISEASES WATCH 63 Jul 15 - Jul 28 2018 WEEKS 29 - 30 VOL 15 ISSUE NO 15 In 2018, all 51 cases recorded were imported cases. The patients had travelled to Thailand (21), the Philippines (10), Cambodia (7), Indonesia (4), Vietnam (3), India (2), Malaysia (1), the Maldives (1), Singapore (1) and one of them had been to multiple countries during the incubation period.Among the 33 patients with positive dengue virus genomic sequences detected in serum samples by polymerase chain reaction, the most common type of dengue virus was type 1 (19, 57.6%), followed by type 2 (seven, 21.2%) and type 3 (seven, 21.2%).

The monthly ovitrap index for Aedes albopictus for June rose to 11.3 per cent from 10.2 per cent in May, indicating that mosquito infestation was slightly more extensive in the areas surveyed. In view of the current hot and humid weather with frequent showers which is favourable to mosquito breeding, the public should step up anti-mosquito measures to prevent DF and other mosquito-borne diseases. Members of the public are reminded to protect themselves from mosquito bites and help prevent their proliferation.

Protect yourselves against bites ✦ Wear loose, light-coloured long-sleeved tops and trousers; ✦ Use DEET-containing insect repellent on exposed parts of the body and clothing; and ✦ Take additional preventive measures when engaging in outdoor activities: • Avoid using fragrant cosmetics or skin care products; and • Re-apply insect repellents according to instructions.

Special notes when travelling abroad ✦ Before the trip • If going to affected areas or countries, arrange a consultation with doctor at least six weeks before the trip, and have extra preventive measures to avoid mosquito bite. ✦ During the trip • If travelling in endemic rural areas, carry a portable bed net and apply permethrin (an insecticide) on it. Permethrin should NOT be applied to skin; and • Seek medical attention as early as possible if feeling unwell. ✦ Upon returning to Hong Kong • Travellers who return from affected areas should apply insect repellent for 14 days after arrival in Hong Kong. If feeling unwell e.g. run a fever, should seek medical advice promptly, and provide travel details to doctor.

Help prevent vector proliferation ✦ Prevent accumulation of stagnant water • Change the water in vases once a week; • Clear the water in the saucers under potted plants every week; • Cover water containers tightly; • Ensure air-conditioner drip trays are free of stagnant water; and • Put all used cans and bottles into covered dustbins. ✦ Control vectors and reservoir of the diseases • Store food and dispose of garbage properly.

Pregnant women and children of six months or older can use DEET-containing insect repellent. For children who travel to countries or areas where mosquito-borne diseases are endemic or epidemic and where exposure is likely, children aged two months or above can use DEET-containing insect repellents with a concentration of DEET up to 30%.

For more information about vector-borne diseases, please visit the CHP website at: https://www.chp.gov.hk/en/healthtopics/ content/24/34622.html.

References 1World Health Organization (2018). Dengue and severe dengue. Available at: http://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue, accessed on July 25, 2018.

Review of acute infectious conjunctivitis (ACJ) in Hong Kong, 2014-2018 (as of July 31, 2018) Reported by Dr Shirley TSANG, Scientific Officer, Respiratory Disease Office, Surveillance and Epidemiology Branch, CHP

Acute infectious conjunctivitis (ACJ), commonly known as “red eye” or “pink eye”, is an inflammation of the conjunctiva (the outermost layer of the eye and the inner surface of the eyelids). Clinically, patients usually present with eye redness and discharge. Other symptoms may include eyelid swelling, foreign body sensation, excessive tearing, itchiness, pain and sensitivity to light.Vision is not affected unless there is scarring of the cornea after the infection.The disease can affect people of all ages, but COMMUNICABLE DISEASES WATCH 64 Jul 15 - Jul 28 2018 WEEKS 29 - 30 VOL 15 ISSUE NO 15 children aged under five years are most frequently affected. ACJ is a highly infectious disease and able to spread widely in the community. It is usually transmitted through direct contact with discharge from the eyes or upper respiratory tract of infected people, or indirectly through contaminated fingers, clothing, and use of contaminated articles, such as shared eye makeup applicators, towels and topical eye medications. The disease is usually a mild, self-limited disease and clinical symptoms often subside in one to two weeks if properly treated.

This article reviewed the ACJ outbreaks recorded by the Centre for Health Protection (CHP) of the Department of Health from 2014 to 2018 (as of July 31, 2018).

From 2014 to 2018 (as of July 31, 2018), CHP recorded 27 reports of ACJ outbreaks, affecting a total of 200 persons. There were one to nine outbreaks each year from 2014 to 2017 (Figure 1). In the first seven months of 2018, eight ACJ outbreaks have been recorded. The number of persons affected in each outbreak ranged from three to 24 persons with a median of six persons. No obvious seasonal pattern was observed for ACJ in the past four years (from 2014 to 2017) (Figure 2). Among the 27 outbreaks, 12 outbreaks (44%) occurred in kindergartens/ child care centres, three (11%) in primary schools, two (7%) in residential care homes for the elderly, one (4%) in a hospital and eight (30%) in other institutions. The remaining one was a home outbreak. Figure 1 - Number of ACJ outbreaks, 2014-2018 (*as of July 31, 2018). CHP also monitors the disease activity of ACJ in the community through sentinel surveillance systems. The average weekly consultation rates for ACJ among sentinel general practitioners (GP) ranged from 1.1 to 3.2 per 1 000 consultations in the past four years (from 2014 to 2017). That among sentinel General Outpatients Clinics (GOPC) ranged from zero to 5.8 per 1 000 consultations. There is no obvious seasonal pattern observed (Figure 3). The surveillance data showed that the consultation rate for ACJ among sentinel GP had increased in the period from May to July this year with the weekly rate persistently above two per 1 000 consultations, as compared with less than two per 1 000 consultations in the first three months. The corresponding rates among GOPC fluctuated in the range about two to 3.5 per 1 000 consultations in this year. Figure 2 - ACJ outbreaks reported to CHP by month, 2014 -2017.

ACJ can be caused by bacteria or viruses. Haemophilus influenzae and Staphylococcus aureus are the commonest bacterial causes, while adenoviruses and enteroviruses are mainly responsible for viral conjunctivitis. Among the 704 eye swabs collected from ACJ patients through the sentinel system for bacterial culture from 2014 to 2018 (up to June 2018), 90 specimens (13%) yielded positive cultures. Haemophilus influenzae (42/90, 47%) and Staphylococcus aureus (15/90, 17%) were the commonest bacteria isolated. For the throat swabs collected from ACJ patients within the same period, 74 specimens (74/392, 19%) yielded positive results by polymerase chain reaction, and adenovirus accounted for 20% Figure 3 - Weekly consultation rates of acute conjunctivitis reported by sentinel general practitioners and sentinel (15/74) of all positive specimens. general outpatient clinics, 2014-2018 (*as of July 31, 2018).

More information on ACJ is available on the CHP website at: https://www.chp.gov.hk/en/healthtopics/content/24/6529.html.

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To prevent ACJ, members of the public are advised to take heed of the following preventive measures:

1. Observe good personal hygiene: ✤ Avoid sharing personal items such as towels, toilet articles, and pillowcases with other people; ✤ Avoid sharing eye medicines (including eye drops), eye makeup, contact lenses and other items that may come into contact with eyes; and ✤ Minimise hand-to-eye contact and if such contact is unavoidable, wash hands thoroughly with soap and water before and after contact with the eyes.

2. When suffering from infectious conjunctivitis: ✤ Seek early medical attention; ✤ Avoid touching or rubbing the infected eyes; ✤ Wash personal items such as bed linen, pillowcases and towels in hot water and detergent; ✤ Properly dispose items soiled with eye or respiratory secretions; ✤ Avoid wearing eye makeup or contact lenses; and ✤ Symptomatic children should seek medical advice and stop attending schools/institutions and avoid going to swimming pools and other crowded public places.

NEWS IN BRIEF

A domestic cluster of pertussis The Centre for Health Protection (CHP) is investigating a domestic cluster of pertussis affecting a three-year-old girl and her 41-year-old mother.The mother had presented with productive cough, runny nose, sore throat and shortness of breath since May 24, and was admitted to a private hospital on June 28. Her nasopharyngeal swab (NPS) collected on June 28 was tested positive for Bordetella pertussis. She was treated with azithromycin. Her condition was stable and she was discharged on June 30.

The girl presented with mild dry cough on July 3 and attended the out-patient clinic of a private hospital on July 7 and 13 respectively. Her NPS collected on July 13 was tested positive for Bordetella pertussis. She was treated with azithromycin. Her condition was stable and did not require hospitalisation.

The two patients had no travel history during the incubation period. The daughter had received four doses of Diphtheria, Tetanus, acellular Pertussis & Inactivated Poliovirus Vaccine according to the schedule of Hong Kong Childhood Immunisation Programme whereas the mother was unsure about her vaccination history against pertussis. Other household contacts were asymptomatic and they were given chemoprophylaxis.

A sporadic case of listeriosis On July 26, 2018, CHP recorded a case of listeriosis affecting an eight-month-old girl with good past health. She had presented with fever, vomiting and diarrhoea since July 13. She attended an emergency medicine centre of a private hospital on July 16 and was referred to a public hospital for admission on the same day. Her collected on July 24 grew Listeria monocytogenes. She was treated with antibiotics and her condition was stable. Epidemiological investigation could not identify any high-risk food consumed during the incubation period. She had no recent travel history and her household contacts remained asymptomatic.

A sporadic case of psittacosis In July 2018, CHP recorded a sporadic case of psittacosis affecting a 36 year-old domestic helper with good past health. She had presented with fever and cough with sputum since June 27 and was admitted to a public hospital on July 4. Her chest X-ray showed left lower zone consolidation.The clinical diagnosis was pneumonia. Her nasopharyngeal aspirate taken on July 5 was tested positive for Chlamydia psittaci DNA by PCR. She was treated with antibiotics. She remained stable and was discharged on July 11. Epidemiological investigation revealed that her employer’s family had kept two pet parrots since March 2018. The parrots were reported asymptomatic. She denied direct contact with them and did not need to take care of the parrots and the cages but the parrots were kept in the living room. She had no recent travel history and denied contact with any other sick bird or bird carcass during the incubation period. The employer’s family remained asymptomatic. The employer reported to have released the parrots after the helper was sick. CHP visited the patient’s home with the Agricultural, Fisheries and Conservation Department (AFCD) on July 18 and no parrots were identified.

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EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Consensus Recommendations on School Closure due to Seasonal Influenza Reported by Dr YH LEUNG, Senior Medical and Health Officer, Communicable Disease Division, Surveillance and Epidemiology Branch, CHP.

School closure has been adopted from time to time as a non-pharmacological intervention during influenza pandemic as well as seasonal influenza epidemics1,2. It had been recognised that in pandemic preparedness plans, rationales for school closure were that children are thought to be important vectors of transmission and more infectious and susceptible to most influenza strains than adults, and high contact rates in schools favour transmission1.

In general, there are two types of school closure namely reactive school closure or proactive school closure3. Reactive school closure refers to closure of a school (or suspension of classes) when many students and/ or staff are ill or absent. Proactive school closure refers to closure of a school (or suspension of classes) before substantial transmission among students occurs.

Scientific evidence on the impact on influenza transmission by school closure The United Kingdom (UK) Department of Health, the Australian Department of Health and Ageing, and the National Collaborating Centre for Infectious Diseases in Canada had conducted three separate systematic reviews on the effectiveness of school closure for influenza control with consistent findings regarding the effectiveness of school closure for influenza control, the threshold triggering school closure as well as the duration of closure4-9.

Published evidence suggested that school closure is able to reduce influenza transmission amongst children. In contrast, evidence regarding the effects on adults is less consistent, but generally transmission amongst adults appears to be relatively unaffected by school closure. The effect of school closure is greater on peak incidence (20 to 60% reduction) than on cumulative attack rate (0 to 40% reduction). It suggests that school closure may have utility as a short-term strategy to forestall the impacts of influenza on healthcare services.

Studies also showed that closing schools would delay the peak of the epidemic, usually by no more than one to three weeks. However, increase in the overall duration of the epidemic of one to three weeks was commonly predicted. School closure is more likely to have the greatest effect if the virus has low transmissibility and if age-specific attack rates are higher in children than in adults. In addition, school closure is also likely to be more effective if it is implemented relatively early in the epidemic.

There is little evidence to suggest an appropriate threshold to trigger school closure. School closure duration of less than two weeks may have limited influence on community transmission and the published evidence does not allow an estimate of the optimum duration of school closure to be made.

Given the aim of school closure is to reduce contact between students in the school, school closure should be accompanied by advice that children should avoid gathering in large groups3,5. If students congregate in a setting other than a school, they will continue to spread the virus, and the benefits of school closure will be greatly reduced, if not negated3.

Overseas practice Review of practice elsewhere found that most health authorities including Mainland China, Macao, Taiwan, United States of America (US), UK, Singapore and Japan do not have established criteria for triggering territory-wide school closure due to seasonal influenza epidemics.

COMMUNICABLE DISEASES WATCH 67 Jul 29 - Aug 11 2018 WEEKS 31 - 32 VOL 15 ISSUE NO 16 Local situation Territory-wide school closure for primary schools and pre-primary institutions due to influenza was implemented in 2008, 2009 and 2018 in Hong Kong.The decisions were made based on the prevailing situations and there have been no established criteria to trigger territory-wide school closure locally.

A local study was conducted after the territory-wide closure of primary schools and pre-primary institutions in response to the three paediatric deaths due to seasonal influenza in March 2008, which could not find a substantial effect on community transmission10. Regarding the territory-wide closure of primary schools and pre-primary institutions in June 2009 in response to the influenza pandemic due to influenza A(H1N1)pdm09 virus, a local study found that only after subsequent closure of secondary schools for the summer vacation was associated with substantially lower transmission across all age groups11.

Potential negative impact associated with school closure School closure is associated with high economic, social and educational costs and could potentially disrupt healthcare provision via increased absenteeism of clinical staff attending to their children9. Studies from US, Australia and Taiwan suggested that 16 to 45% of parents would need to take leave to supervise children at home, 16 to 18% of parents would lose income, and about 20% of households would have difficulty arranging childcare12.

Recommendation on territory-wide school closure due to seasonal influenza epidemics The Scientific Committee on Vaccine Preventable Diseases (SCVPD) of the Centre for Health Protection (CHP) of the Department of Health held a meeting on July 20, 2018 to discuss the scientific evidence and practice on the criteria for triggering territory-wide school closure due to seasonal influenza epidemics. The Committee noted that there is so far no scientific evidence or international guidelines/ consensus to suggest an appropriate threshold to trigger territory-wide school closure due to seasonal influenza epidemics. Hence, SCVPD concluded that there is no scientific basis to establish local criteria for territory-wide school closure due to seasonal influenza epidemics.

Recommendations on reactive closure of an individual school with influenza outbreaks In 2008, an Expert Group was set up to investigate the three paediatric deaths due to seasonal influenza. The Expert Group recommended that closure of an individual school during influenza outbreaks may be considered taking reference from (but not solely dictated by) certain indicators such as13: (i) Any death in the school due to influenza in otherwise healthy children; (ii) There are two or more intensive care unit admissions; (iii) The hospitalisation rate is more than 1%; or (iv) The sick leave rate is 10% or more.

According to the experience in investigation and management of influenza/ influenza-like illness (ILI) outbreaks in schools and pre- 2016 2017 2018 Total primary institutions in the past ten years, CHP found that the indicators concerning hospitalisation rate and sick leave rate Outbreaks with respectively are not practicable owing to the relatively small ILI attack rate ≥ 10% 17 (11%) 4 (4%) 10 (4%) 31 (7%) capacity of students among pre-primary institutions in Hong Kong. If such indicators were implemented, at least 7 to 21% of the pre-primary institutions with influenza/ ILI outbreaks in the Outbreaks with hospitalisation rate > 1% 32 (21%) 25 (27%) 42 (19%) 99 (21%) recent three years would have been closed which was not warranted from the public health perspective (Table 1). Table 1 - Number of influenza/ILI outbreaks in pre-primary institutions Moreover, the suggested duration of closure was not specified in with attack rate ≥ 10% or hospitalisation rate > 1% in 2016 to 2018 the recommendation. (up to March).

Based on the review of the local epidemiology, scientific literature and overseas practice, SCVPD recommended that closure of an individual school with influenza/ ILI outbreaks may be considered taking reference from the following indicators: (i) Any death of healthy children in the school due to influenza; (ii) Tw o o r m o r e c h i l d r e n r e q u i r e d i n t e n s i v e c a r e u n i t a d m i s s i o n d u e t o i n f l u e n z a ; o r (iii) ILI attack rate among children is 20% or more.

In addition to the above indicators, factors including the number of staff affected (which may potentially affect operation of the school), epidemic trend of the outbreak and effectiveness of control measures etc., should also be taken into consideration for advising school closure during an influenza/ ILI outbreak.

COMMUNICABLE DISEASES WATCH 68 Jul 29 - Aug 11 2018 WEEKS 31 - 32 VOL 15 ISSUE NO 16 SCVPD also noted that there is no international consensus/ guidelines on the optimum closure duration regarding closure of an individual school due to influenza/ ILI outbreak. As influenza has an incubation period of about one to four days and a communicable period of about three to five days in general, SCVPD considered that seven days of school closure is appropriate for interrupting influenza transmission within the affected school.

References 1Cauchemez S, et al. Closure of schools during an influenza pandemic. Lancet Infect Dis. 2009;9:473-81. 2Cauchemez S, et al. Estimating the impact of school closure on influenza transmission from Sentinel data. Nature. 2008;452:750-4. 3World Health Organization. Reducing transmission of pandemic (H1N1) 2009 in school settings. A framework for national and local planning and response. September 2009. 4National Collaborating Centre for Infectious Diseases, Canada. Effectiveness of School Closure for the Control of Influenza A Review of Recent Evidence. March 2014. 5United Kingdom Department of Health. Impact of School Closures on an Influenza Pandemic. Scientific Evidence Base Review. May 2014. 6Jackson C, et al. School closures and influenza: systematic review of epidemiological studies. BMJ Open. 2013;3:e002149. 7Jackson C, et al.The effects of school closures on influenza outbreaks and pandemics: systematic review of simulation studies. PLoS One. 2014 ;9(5):e97297. 8Australian Government Department of Health and Ageing. Social Distancing. Evidence Summary. 2015. 9Rashid H, et al. Evidence compendium and advice on social distancing and other related measures for response to an influenza pandemic. Paediatr Respir Rev. 2015;16:119-26. 10Cowling B, et al. Effects of School Closures, 2008 Winter Influenza Season, Hong Kong. Emerg Infect Dis. 2008;14:1660-62. 11Wu JT, et al. School closure and mitigation of pandemic (H1N1) 2009, Hong Kong. Emerg Infect Dis. 2010 March;16:538-41. 12Cauchemez S, et al. School closures during the 2009 influenza pandemic: national and local experiences. BMC Infect Dis. 2014;14:207. 13Press release. Expert Group Report on deaths of three children released. Available at: http://www.info.gov.hk/gia/general/200804/18/P200804180245.htm.

The 18th Tripartite Meeting on Prevention and Control of Infectious Diseases and Joint Emergency Response Exercise Reported by the Emergency Response and Information Branch and the Communicable Disease Surveillance and Intelligence Office, Communicable Disease Division, Surveillance and Epidemiology Branch, CHP.

The 18th Tripartite Meeting on Prevention and Control of Infectious Diseases hosted by the Health and Family Planning Commission of Guangdong Province was successfully held in Zhuhai, Guangdong on August 2 and 3, 2018.

More than 60 public health and medical experts from the health authorities of Guangdong, Hong Kong and Macao attended the two-day meeting. The participants had in-depth discussion and experience sharing in various issues including the updated situation of communicable diseases in the three places, prevention and control of vaccine preventable diseases, and capacity building on public health emergency.

Guangdong, Hong Kong and Macao had also reviewed the co-operation and preparedness of the three places against communicable diseases and reached consensus at the meeting to further enhance the tripartite co-operation and communication on prevention and control of communicable diseases.

As part of the 18th Tripartite Meeting on Prevention and Control of Communicable Diseases, the three health authorities conducted a joint emergency response exercise code-named “Whirlwind” to test the responses to emerging infectious diseases on August 3, 2018. This was the first time Guangdong, Hong Kong and Macao ever conducted a joint emergency response exercise on the prevention and control of infectious diseases.

The exercise simulated the scenario of an imported case of Middle East respiratory syndrome (MERS) occurring in Guangdong with close contacts travelling to Hong Kong and Macao. MERS is one of blueprint priority diseases for research and development identified by the World Health Organization (WHO). Those diseases pose a public health risk because of their epidemic potential and for which there are no, or insufficient, countermeasures.The three places executed a joint response to the health emergency in accordance with the “Agreement of Co-operation on Emergency Public Health Incidents in Hong Kong, Guangdong and Macao”.

This exercise comprised a table-top exercise integrated with an on-site drill component. The three places exchanged views on the case detection, communication, responses, co-operation and improvement measures with respect to emerging infectious diseases. Experience of managing emerging infectious diseases of the three places were also shared, with issues relating to macro-management, among others, were thoroughly discussed. Apart from introducing the approach to dealing with MERS, the representatives from Guangdong also introduced their approach to preventing the outbreak of Ebola virus disease in West Africa and preventing Zika virus transmission, and shared their experience of adopting the collaborative prevention and control mechanism, setting up health emergency response teams, as well as notification of epidemics.

COMMUNICABLE DISEASES WATCH 69 Jul 29 - Aug 11 2018 WEEKS 31 - 32 VOL 15 ISSUE NO 16 During the exercise, the health emergency response co-operation mechanism among the three places was thoroughly examined. The exercise not only enhanced the capacities of three places in carrying out joint response actions, but also helped fine-tuning the joint response to emerging infectious diseases for the Guangdong-Hong Kong-Macao Greater Bay Area. In the exercise, implementation of various emergency response measures was successfully tested, including alert monitoring and analysis, case detection and notification, on-site investigation and emergency response, as well as identification and management of close contacts.

With the ongoing implementation of the “Belt and Road Initiative” and development of the “Guangdong-Hong Kong-Macao Greater Bay Area”, transboundary trade and traffic in the three places are expected to become increasingly frequent.The need to formulate a comprehensive mechanism to counter the threats of imported emerging infectious diseases therefore has become an increasingly pressing public health issue.The exercise provided a valuable experience to facilitate the formulation of a comprehensive plan in this regard.

Photo 1 - The Director General of the Photo 2 - Representatives from the health Photo 3 - Participants at the 18th Tripartite Meeting Guangdong Provincial Health and Family authorities of Guangdong, Hong Kong and on Prevention and Control of Communicable Diseases. Planning Commission, Mr Duan Yufei (centre); Macao participated in the joint emergency the Director of Health of Hong Kong, Dr response exercise code-named “Whirlwind” to Constance Chan (right); and the Director of the test the responses to emerging infectious Health Bureau of Macao, Dr Lei Chin-ion (left), diseases. signed the joint minutes of the 18th Tripartite Meeting on Prevention and Control of Communicable Diseases.

NEWS IN BRIEF An imported case of leptospirosis On July 30, 2018, the Centre for Health Protection (CHP) recorded a case of leptospirosis affecting a 69-year-old man with good past health. He presented with fever, arthralgia, vomiting and diarrhoea on July 3, 2018. He was admitted to a public hospital on July 5. Blood tests showed thrombocytopenia and derangement of liver function. His condition was stable. Paired sera on July 6 and July 10 showed more than four-fold increase in antibody titre against Leptospira serogroup Autumnalis by microscopic agglutination test. He was treated with antibiotics and was discharged on July 12.

Epidemiological investigation revealed that the patient lived in Guangdong and came to Hong Kong to seek medical treatment after disease onset.While in Guangdong, he went swimming in a local river daily and reported drinking filtered tap water at home without boiling. He also had gardening activities and kept a cat at home. He recalled no exposure to rodents or stray dogs. His wife and daughter presented with similar symptoms on July 1 and June 10 respectively. Both had sought medical attention in Guangdong and had recovered. Other home contact remained asymptomatic.

A sporadic case of necrotising fasciitis caused by Vibrio vulnificus On August 2, 2018, CHP recorded a sporadic case of necrotising fasciitis caused by Vibrio vulnificus affecting an 81-year-old man with underlying illnesses. He presented with fever and left hand painful swelling on July 29, and was admitted to a public hospital on July 31.The clinical diagnosis was necrotising fasciitis and he was transferred to another public hospital on the same day for further management. Multiple surgical debridement operations were performed and he was managed in the intensive care unit post-operatively. His left hand tissue collected on August 1 grew Vibrio vulnificus. He was treated with antibiotics and his condition was critical. Epidemiological investigation revealed that the patient swam daily at TungWan Beach in .There was no history of wound or injury. He had no recent travel history. He lived with his wife who remained asymptomatic.

A probable case of sporadic Creutzfeldt-Jakob disease CHP recorded a probable case of sporadic Creutzfeldt-Jakob disease (CJD) on August 9, 2018, affecting a 61-year-old woman with good past health. She presented with rapidly progressive dementia, dullness and confusion since early May 2018. Subsequently, she developed left-sided weakness and slurred speech, and was admitted to a public hospital on June 3. She was noted to have akinetic mutism, myoclonus and choreoathetoid movement. Findings of electroencephalography were compatible with CJD. She was discharged on August 2. On August 7, she was admitted to another public hospital for increase in myoclonic jerks. Her condition was stable. No risk factors for either iatrogenic or variant CJD were identified. She was classified as a probable case of sporadic CJD.

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IMPACT Mobile APP: Interactive Media Awards 2018 The Fifth edition of the Interhospital Multi- disciplinary Programme on Antimicrobial Chemotherapy (IMPACT) was launched in November 2017. With support from CHP, IMPACT has its own website version as well as mobile applications (Android and iOS). This facilitates health professionals to obtain useful information from their computers or smartphones. The new IMPACT Mobile APP and Website excels its printed version as they contain value-added features: 1) medical calculators; 2) antibiograms from the Public Health Laboratory Services Branch of the Department of Health, Hospital Authority and private hospitals; and 3) search function.

The Infection Control Branch (ICB) of CHP has been providing secretariat and technical support to the Editorial Board of IMPACT. Dr WONG Figure 1 - IMA Award 2018 plaque - Figure 2 - QR codes to download IMPACT. Tin-yau, Head of ICB, is delighted to announce IMPACT Mobile APP . that the IMPACT Mobile APP has received the “Outstanding Achievement” in both Healthcare and Education categories in the Interactive Media AwardsTM (IMA) 2018. IMA is an international awards competition recognising excellence in web design, development, management, support and promotion.The “Outstanding Achievement” award is the second highest honor bestowed by IMA.Amongst the 216 entries in the “Healthcare” category and 202 entries in the “Education” category, IMPACT Mobile APP was selected to be awarded as judges considered the APP achieved a very high standard in most criteria including planning, execution and overall professionalism.

CA-MRSA cases in July 2018 In July 2018, CHP recorded a total of 91 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 55 males and 36 females with ages ranging from nine days to 83 years (median: 31 years). Among them, there were 66 Chinese, 10 Filipinos, 5 Pakistani, 2 Indian, 1 Caucasian, 1 Bangladeshi, 1 Indonesian and 5 of unknown ethnicity.

Ninety cases presented with uncomplicated skin and soft tissue infections while the remaining case had invasive CA-MRSA infection. The invasive case affected a 20-year-old woman with history of left knee injury. She presented with left knee pain and swelling since July 20. She attended the outpatient department of a private hospital and was admitted from July 21 to 22 for management. Left knee arthroscopy performed on July 21 showed active inflammation and synovitis with turbid joint fluid. Joint fluid collected during arthroscopy was cultured positive for CA-MRSA. She was diagnosed with septic arthritis of left knee. She was re-admitted on July 26 for further surgical and antibiotic treatments. She remained in a stable condition and was discharged on August 4.

Separately, the isolate of one case affecting a 73-year-old woman was found to be resistant to mupirocin.The patient presented with on her right shoulder in early July. Her symptoms improved after treatment with antibiotics and wound drainage.The patient was a tourist and left Hong Kong on July 22, 2018.

Among the 91 cases, two sporadic cases involved healthcare workers who were nurses working in a public hospital and a private clinic. Investigation did not reveal any epidemiologically linked cases. Besides, three household clusters, with each affecting two persons, were identified in July.

Scarlet fever update (July 1, 2018 – July 31, 2018) Scarlet fever activity in July decreased as compared with that in June. CHP recorded 153 cases of scarlet fever in July as compared with 196 cases in June.The cases recorded in July included 83 males and 70 females aged between one and 37 years (median: six years). There were three institutional clusters occurring in two kindergartens/ child care centres and a primary school, affecting a total of eight children. No fatal cases were reported in July.

COMMUNICABLE DISEASES WATCH 71 Aug 12 - Aug 25 2018 WEEKS 33 - 34 VOL 15 ISSUE NO 17

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie LAM / Dr Albert AU / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C, Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Latest situation of dengue fever in Hong Kong Reported by Dr Jess YIM, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

In Hong Kong, dengue fever (DF) has been a notifiable disease since March 1994. From 2008 to 2017, the Centre for Health Protection (CHP) of the Department of Health recorded a total of 806 DF cases, with the annual number of cases ranging between 30 and 124. Local cases had been recorded in 2010 (four cases) and each year from 2014 to 2017 (one to four cases per year). In 2018 (as of August 29), CHP recorded 89 DF cases, including 27 local and 62 imported cases.

The local outbreak of DF in 2018 The first four local DF cases in 2018 were notified to CHP on August 14. Epidemiological investigations and control measures were carried out immediately. Subsequently, more local cases were recorded. From August 14 to 29, a total of 27 cases were confirmed. The 27 cases involved 16 males and 11 females, with ages ranging from 17 to 84 years (median: 55 years). Their dates of symptom onset ranged between July 31 and August 22 (Figure 1). Fever was the commonest presenting symptom (26 cases, 96.3%), followed by myalgia (22 cases, 81.5%), headache (19 cases, 70.4%), rash (15 cases, 55.6%) and arthralgia (13 cases, 48.1%). Twenty-three patients (85.2%) required hospitalisation. All patients have remained in stable condition and there were no severe cases so far. Figure 1 - Epidemic curve by date of onset of symptom (N=27).

While the 27 cases lived in various districts in Hong Kong, epidemiological investigations found that they were linked to two separate clusters, one in Lion Rock Park/ Wong Tai Sin (18 cases) and the other in Cheung Chau (nine cases). Among the 27 cases, 17 had been to the Lion Rock Park during the incubation period, including four patients who worked at the park and another 13 patients visiting the park. One patient reported that he had not visited Lion Rock Park but had visited the vicinity of Wong Tai Sin MTR Station during the incubation period. Among the remaining nine cases, seven live in Cheung Chau while the other two had visited Cheung Chau during the incubation period (Figure 2). The genetic sequencing results were compatible with the epidemiological findings. Figure 2 - Locations of the residences and local movements of the 27 cases.

COMMUNICABLE DISEASES WATCH 72 Aug 12 - Aug 25 2018 WEEKS 33 - 34 VOL 15 ISSUE NO 17 Actions taken to control the outbreak Upon notification and laboratory confirmation of the local DF cases, CHP immediately commenced epidemiological investigations. CHP interviewed patients for their local movements both during the incubation period and after symptoms onset so as to inform promptly the Food and Environmental Hygiene Department for vector investigation and mosquito control. CHP also conducted site visits and field investigations by questionnaire surveys at the patients’ residences for active case finding and arranging blood tests. Health talks were organised to educate the public on mosquito control and preventive measures. A telephone hotline (2125 1122) has been set up by CHP since August 14, 2018 to facilitate surveillance and answer public enquiry. Persons who have been to places visited by the patients during their incubation period or after onset of symptoms were advised to call the CHP’s hotline for laboratory investigation or referral as appropriate.

As Lion Rock Park was identified to be a place with active transmission in this outbreak, it has been closed since the evening on August 17. Members of the public were advised not to visit Lion Rock Park during the closure period in order to prevent contracting DF. Moreover, scientific studies have shown that infected persons can transmit the virus to mosquitoes through mosquito bites even if they remain asymptomatic or before their onset of symptoms, leading to further spread of the disease1,2. Hence, people who had visited Lion Rock Park were advised to apply insect repellent for 14 days upon their last visit. Those with DF symptoms were advised to seek medical advice as early as possible. Meanwhile, people who reside in or visit Cheung Chau should also be advised to apply insect repellent during their stay and continue applying for 14 days after their last day of stay to prevent infection and secondary spread.

CHP has enhanced the detection of suspected DF cases with the Hospital Authority (HA) through the activation of an electronic reporting platform “e-Dengue” on August 16, 2018 to allow prompt monitoring and review of suspected cases for early public health investigation. Doctors are requested to notify CHP and HA when a laboratory test request for dengue fever is made.

Press stand-ups and media interviews were conducted to keep the public informed of the latest situation. CHP has issued letters to local doctors and hospitals to alert them to the latest situation of local DF and remind them to enhance surveillance. CHP has also issued letters to schools and institutions to remind them to step up mosquito control and prevention measures. A mini-web on the CHP website was set up to provide the latest information, locations of the residences and local movements of the local DF cases. CHP has enhanced public health education through a designated website, television and radio stations. A variety of health education materials were produced to raise public awareness.

Risk assessment of the current situation and health advice to the public This is the first local outbreak of DF of this scale since the major local outbreak in Ma Wan in 2002. Two sources have been identified and the situation is evolving. It is possible that further cases are occurring in the community. Prompt, continuous, intensive and effective anti-mosquito operation must be carried out at this stage to prevent DF from further spread and becoming an endemic disease.

Members of the public can help in the prevention of DF by taking part in mosquito control actions and adopting personal protective measures against mosquito bites. The following preventive measures should be taken to prevent accumulation of stagnant water and eliminate mosquito breeding sites:- ✦ Thoroughly check all gully traps, roof gutters, surface channels and drains to prevent blockage; ✦ Scrub and clean drains and surface channels with an alkaline detergent compound at least once a week to remove any deposited mosquito eggs; ✦ Properly dispose of refuse, such as soft drink cans, empty bottles and boxes, in covered litter containers; ✦ Completely change the water of flowers and plants at least once a week. The use of saucers should be avoided if possible; ✦ Level irregular ground surfaces before the rainy season; and ✦ Avoid staying in shrubby areas.

Members of the general public are also advised to protect themselves from mosquito bite by taking the following measures:- ✦ Wear loose, light–coloured, long-sleeved tops and trousers, and apply effective mosquito repellent containing DEET to exposed parts of the body and clothing; ✦ Use mosquito screens or bed nets when the room is not air-conditioned; and ✦ Place anti-mosquito devices near entrances such as windows and doors to prevent mosquitoes from entering indoor.

More information on preventive measures could be found in the website of CHP at http://www.chp.gov.hk/en/content/9/24/19.html. For the latest situation of the DF outbreak, please visit the designated DF website at https://www.chp.gov.hk/en/features/38847.html.

References 1Duong V, Lambrechts L, Paul RE, et al. Asymptomatic humans transmit dengue virus to mosquitoes. Proc Natl Acad Sci U S A. 2015 Nov 24;112(47): 14688-93. 2Ten Bosch QA, Clapham HE, Lambrechts L, et al. Contributions from the silent majority dominate dengue virus transmission. PLoS Pathog. 2018 May 3;14(5):e1006965.

COMMUNICABLE DISEASES WATCH 73 Aug 12 - Aug 25 2018 WEEKS 33 - 34 VOL 15 ISSUE NO 17 Stay Vigilant Against Communicable Diseases in the New School Year Reported by the Surveillance Section, Communicable Disease Division, Surveillance and Epidemiology Branch, CHP. Child care centres, kindergartens and schools are vulnerable places for transmission of infectious diseases among students. Moreover, young children may not be able to observe proper personal hygiene and this facilitates the spread of communicable diseases through the close person-to-person contact. Seasonal influenza, hand-foot-mouth disease (HFMD), chickenpox and scarlet fever (SF) are common infections that cause outbreaks in school settings.

It is important for staff and students to observe good personal and environmental hygiene to prevent spread of infectious diseases. In addition, they should also take anti-mosquito measures for prevention of dengue fever.

Seasonal influenza Influenza viruses mainly spread through droplets when infected people cough, sneeze or talk. The infection may also spread by direct contact with the secretions of infected persons. Symptoms may include fever, cough, sore throat, runny nose, muscle pain, fatigue and headache; some may also have vomiting and diarrhoea. The surveillance data of the Centre for Health Protection (CHP) of the Department of Health showed that the overall local influenza activity is currently at a low level, but outbreaks of influenza-like illness in schools may increase after the start of the new school year.

Schools and parents should continue to stay vigilant against influenza as it can cause serious illness even in healthy children. All persons aged six months or above except those with known contraindications are recommended to receive influenza vaccine to protect themselves against seasonal influenza and its complications, as well as related hospitalisations and deaths.

In 2018/19, the Government will continue to provide free and subsidised seasonal influenza vaccination to children aged between six months and under 12 years through the Government Vaccination Programme (GVP) and the Vaccination Subsidy Scheme (VSS) respectively. In addition, CHP will launch the “School Outreach Vaccination Pilot Programme” at primary schools and the “Enhanced VSS Outreach Vaccination” at primary schools, kindergartens and child care centres to further encourage schools to arrange outreach vaccination activities for students.

Hand-foot-mouth disease (HFMD) HFMD is a common disease in children caused by enteroviruses such as coxsackie viruses and enterovirus 71 (EV71). In Hong Kong, the usual peak season for HFMD and EV71 infection is from May to July and a smaller peak may also occur from October to December. In the 2018 summer peak, the HFMD activity started to increase in May, peaked in June and returned to baseline level in mid-August. As of mid-August this year, the number of cases of EV71 infection recorded was lower but that of severe enterovirus infections other than EV71 and poliovirus was higher than that in the same period of last year. It is expected that some sporadic institutional outbreaks of HFMD may occur after the start of the new school year. Figure 1 – Number of HFMD outbreaks in school settings, 2016-2018 (as of August 27, 2018). Chickenpox Chickenpox is one of the commonest childhood viral infections and is highly contagious. In Hong Kong, it is also the most commonly reported notifiable infectious disease. There are two seasonal peaks: the number of chickenpox cases usually starts to rise in October and peaks in December and January; while a smaller peak is also observed in June and July. Institutional outbreaks of chickenpox occur commonly in the community with the majority in pre-primary institutions (including kindergartens, child care centres, etc.) as well as primary and secondary schools. Chickenpox outbreaks in school settings showed substantial increase from September onwards following the seasonal trend in the past few years. Figure 2 – Number of chickenpox outbreaks in school settings, January 2016 to July 2018 (as of August 17, 2018).

COMMUNICABLE DISEASES WATCH 74 Aug 12 - Aug 25 2018 WEEKS 33 - 34 VOL 15 ISSUE NO 17 Scarlet fever (SF) SF is a bacterial infection caused by Group A Streptococcus. It mostly affects children. SF is transmitted through either respiratory droplets or direct contact with infected respiratory secretions. The local SF activity is usually higher from November to March and from May to June. It is currently at a low level but is expected to increase after the start of the new school year.

Dengue fever (DF) DF is an acute febrile viral illness with symptoms such as high fever, severe headache, pain behind the eyes, rash, muscle and joint pain. The disease is transmitted by mosquitoes. The symptoms of first infection are usually mild, but subsequent infections from other serotypes of dengue virus may result in severe dengue and progress to circulatory failure, shock and even death. Since August 14, 2018, 27 local cases of DF have been recorded in Hong Kong this year (as of August 28).

Schools are advised to take stringent preventive measures in order to prevent accumulation of stagnant water and eliminate mosquito breeding sites. Staff and students are also advised to protect themselves from mosquito bite by taking measures including: ✦ Wearing loose, light–coloured, long-sleeved tops and trousers, and apply effective mosquito repellent containing DEET to exposed parts of the body and clothing; ✦ Using mosquito screens or bed nets when the room is not air-conditioned; and ✦ Placing anti-mosquito devices near entrances such as windows and doors to prevent mosquitoes from entering indoor.

To prevent outbreaks of communicable diseases, students/ children who develop skin rash, fever, acute respiratory symptoms, diarrhoea or vomiting are strongly advised not to attend school and should seek medical advice. Besides, child care centres, kindergartens and schools should take measures to prevent the spread of communicable diseases, e.g. remind students/ children and staff members to observe good personal, food and environmental hygiene, avoid sharing clothing and slippers among students/ children, etc.

Early detection of the occurrence of communicable disease in schools helps to prevent the diseases’ spread. Child care centres, kindergartens and schools should: ✦ Report suspected/ confirmed cases or outbreaks of communicable diseases among children/staff to the CHP* timely for epidemiological investigation and outbreak control; ✦ Keep personal health record and body temperature for every child properly; ✦ Keep sick leave records of staff properly; ✦ Ensure adequate hand washing facilities and personal protective gear in the schools/ centres; and ✦ Communicate closely with the parents/ guardians to get their support to implement infection control measures.

Children, students or staff members with symptoms of infectious disease (such as fever, influenza-like illness, diarrhoea, vomiting, skin rash, etc.) should not attend school. With the collaborative support from child care centres, kindergartens and schools in the prevention of communicable disease outbreaks in school settings, we can together safeguard a healthy and supportive learning environment for our children.

For the latest information on communicable diseases, please visit the CHP's webpages below: ❖ Influenza (https://www.chp.gov.hk/en/features/14843.html); ❖ Chickenpox (https://www.chp.gov.hk/en/healthtopics/content/24/15.html); ❖ HFMD (https://www.chp.gov.hk/en/features/16354.html); ❖ Scarlet fever (https://www.chp.gov.hk/en/healthtopics/content/24/41.html); ❖ Dengue fever (https://www.chp.gov.hk/en/features/38847.html and https://www.fehd.gov.hk/english/pestcontrol/library/ pdf_pest_control/mosquito_school.pdf); and ❖ Guidelines on Prevention of Communicable Diseases in Schools/ Kindergartens/ Kindergartens-cum-Child Care Centres/ Child Care Centres (http://www.chp.gov.hk/files/pdf/guidelines_on_prevention_of_communicable_diseases_in_schools_ kindergartens_kindergartens_cum_child_care-centres_child_are_centres.pdf).

*Fax: 2477 2770/ Telephone: 2477 2772

COMMUNICABLE DISEASES WATCH 75 Aug 12 - Aug 25 2018 WEEKS 33 - 34 VOL 15 ISSUE NO 17 NEWS IN BRIEF A sporadic case of psittacosis On August 9, 2018, the Centre for Health Protection (CHP) recorded a sporadic case of psittacosis affecting a 35-year-old man with good past health. He presented with fever, cough with sputum, running nose, sore throat, headache and myalgia since August 2. He attended the Accident and Emergency Department of a public hospital on August 5 and August 6 and was admitted for management. His chest X-ray showed left lower zone haziness and the diagnosis was pneumonia. His nasopharyngeal aspirate collected on August 7 was tested positive for Chlamydophila psittaci DNA by polymerase chain reaction (PCR). He was treated with (a course of) antibiotics and his condition improved. He was discharged on August 10. Epidemiological investigation revealed that the patient kept a newly bought parrot at home since mid-July which died in late July. The patient did not know the cause of its death and reported that the bird was well all along. Home visit was conducted and found that the patient kept another five birds at home which were clinically well. Clinical and environmental specimens were taken for investigation. His home contacts remained asymptomatic. Separately, the patient had travelled to Shenzhen for a day trip on July 28 with two friends who remained asymptomatic.

A domestic cluster of pertussis On August 16, 2018, CHP recorded a domestic cluster of pertussis affecting an one-month-old boy and his mother. The boy had presented with cough, runny nose, post-tussive vomiting and reduced appetite since August 5 and was admitted to a public hospital on August 12. His pernasal swab was tested positive for Bordetella pertussis. He was treated with antibiotic. His mother was a 27-year-old female who was found to have cough since July 16 upon contact tracing. She was referred to the Accident and Emergency Department of a public hospital and was admitted on August 16. Her pernasal swab was tested positive for Bordetella pertussis. She was treated with antibiotic.

Both cases had no travel history during incubation period. They remained stable all along and were discharged on August 22 and August 18 respectively. The boy was not yet due for his first dose of diphtheria, tetanus, acellular pertussis and inactivated poliovirus (DTaP-IPV) vaccine while his mother had completed DTaP-IPV vaccine according to the Immunisation Programme.

A sporadic case of necrotising fasciitis caused by Vibrio vulnificus On August 16, 2018, CHP recorded a sporadic case of necrotising fasciitis caused by Vibrio vulnificus affecting a 71-year-old man with underlying illnesses. He presented with fever, left forearm pain, swelling and erythema on August 12, and was admitted to a public hospital on August 13. The clinical diagnosis was necrotising fasciitis. Multiple surgical debridement operations were performed and he required intensive care after the operation. His blood and left forearm deep fascia tissue specimens collected on August 13 grew Vibrio vulnificus. He was treated with antibiotics and his condition was critical. Epidemiological investigation revealed that the patient swam and fished at Tai Po Waterfront Park on August 12. There was no history of wound or injury. He had no recent travel history. He lives with his wife, son, daughter-in-law and two grandsons who remained asymptomatic.

A possible sporadic case of Creutzfeldt-Jakob disease On August 17, 2018, CHP recorded a possible case of sporadic Creutzfeldt-Jakob disease (CJD) affecting a 68-year-old woman with underlying illnesses. She had presented with limb numbness and slow mental response since September 2017 and was admitted to a public hospital on April 27, 2018. She was readmitted to the hospital on July 13, 2018 for neck pain. Upon admission, she was found to have progressive dementia, visual disturbance, pyramidal and extrapyramidal signs, dysarthria, dysphasia and dysphagia. She had no known family history of CJD and no reported risk factors for iatrogenic or variant CJD were identified. She was classified as a possible case of sporadic CJD.

A sporadic case of listeriosis On August 23, 2018, CHP recorded a sporadic case of listeriosis affecting a 35-year-old woman with underlying illnesses. She was admitted to a public hospital for management of her underlying illnesses on August 14. She had developed seizure, fever and diarrhoea after admission on August 14. Her condition deteriorated and was subsequently transferred to Intensive Care Unit on August 20 for further management. Her blood culture collected on August 20 and cerebrospinal fluid collected on August 22 grew Listeria monocytogenes. She was treated with antibiotics. Her condition was critical (as of August 28). She had history of sushi consumption during the incubation period. She had no recent travel history and her household contacts remained asymptomatic.

A sporadic confirmed case of acute Q fever On August 23, 2018, CHP recorded a confirmed case of acute Q fever affecting a 49-year-old male with underlying illness. He has presented with on and off fever and dizziness since July 14, and was admitted to a public hospital on July 19. His blood test showed elevated liver transaminase and he was managed as pyrexia of unknown origin with empirical antibiotics given. His condition was stable and he was discharged on Jul 24. Paired sera collected on July 25 and August 16 showed a four-fold rise in Coxiella burnetii (phase II) polyvalent antibody titre. His clinical diagnosis was acute Q fever and he was put on long term antibiotics. The patient worked in marble engineering industry in Guangdong who reported dusty environment in his workplace while his colleagues there were asymptomatic. He had no history of other high risk exposure. He mainly stayed in Guangdong and only stayed in Hong Kong about two days per week and his home contact in Hong Kong was asymptomatic.

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EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Shirley Tsang / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Update on the dengue fever outbreak in Hong Kong in 2018 Reported by Dr Jess YIM, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Further to the review on the local dengue fever (DF) outbreak recorded in summer this year published on August 30, 2018, this article provides an update on the latest situation of DF in Hong Kong. As of September 11, 2018, the Centre for Health Protection (CHP) of the Department of Health recorded a total of 106 confirmed DF cases this year with 29 and 77 being local and imported cases respectively.

The local outbreak of DF in 2018 The first four confirmed local DF cases in 2018 were notified to CHP on August 14. Epidemiological investigations and control measures have been carried out immediately. Subsequently, more local cases were recorded. A total of 29 cases have been confirmed during the period from August 14 to September 11. The 29 cases involved 16 males and 13 females, with ages ranging from 17 to 84 years (median: 59 years). Their dates of symptom onset ranged between July 31 and August 28 (Figure 1). Fever was the commonest presenting symptom (28 cases, 96.6%), followed by myalgia (24 cases, 82.8%), headache (21 cases, 72.4%), rash (16 cases, 55.2%) and arthralgia (14 cases, 48.3%). Twenty-four patients (82.8%) required hospitalisation and all of them have been discharged.All patients have remained in stable condition and there were no severe cases so far. Figure 1 - Epidemic curve by date of onset of symptoms.

While these 29 local DF cases lived in various districts in Hong Kong, epidemiological investigations found that they were linked to two separate clusters, one in Lion Rock Park/ Wong Tai Sin (19 cases) and the other in Cheung Chau (ten cases).The genetic sequencing results were compatible with the epidemiological findings.

Among the 19 cases involved in the Lion Rock Park/ Wong Tai Sin cluster, 18 had been to Lion Rock Park during the incubation period, including four patients who worked at the park and another 14 patients visiting the park. The remaining patient reported that he had not visited Lion Rock Park but had visited the vicinity of Wong Tai Sin MTR Station during the incubation period. The last case in this cluster had onset of illness on August 20.

Among the ten cases involved in the Cheung Chau cluster, eight live in various places in Cheung Chau while the other two had visited Cheung Chau during the incubation period. Unlike the Lion Rock Park/ Wong Tai Sin cluster, the places visited by the patients scattered over Cheung Chau in particular the Southern part of the island.There was no single hotspot for acquiring DF in Cheung Chau. The last case of this cluster had onset of illness on August 28 and the patient was isolated in mosquito-free environment since August 29.

Separately, five probable local DF cases have been recorded in this period. These were clinically compatible cases with supportive serological test results but without any positive confirmatory laboratory test. Among the five cases, three sought medical advice due to clinical symptoms while the other two were identified through active case finding.The five cases involved three males and two females, with ages ranging from 44 to 77 years (median: 63 years). Their dates of symptom onset ranged between July 23 and August 12 (Figure 1). Fever was the commonest presenting symptom (four cases, 80%), followed by headache (three cases, 60%), arthralgia (two cases, 40%), myalgia (two cases, 40%) and rash (two cases, 40%).Two patients (40%) required hospitalisation and both of them have been discharged. COMMUNICABLE DISEASES WATCH 77 Aug 26 - Sep 8 2018 WEEKS 35 - 36 VOL 15 ISSUE NO 18 Among the five probable local cases, four had been to Lion Rock Park during the incubation period, including one who worked at the park and another three who visited the park, while the remaining case lived in Cheung Chau.The blood samples of all the five patients were tested positive for immunoglobulin M (IgM) antibodies to dengue virus but negative for dengue virus by polymerase chain reaction. For dengue virus antigen test, four samples were tested negative while the remaining one could not be tested due to insufficient quantity. The paired serum samples of four patients did not demonstrate a four-fold or greater change in antibody titres to dengue virus antigens while the remaining patient refused further blood testing for antibody titres. In summary, these laboratory findings suggest that the patients probably had recent dengue fever infection, but laboratory investigations could not confirm the diagnosis.

Risk assessment of the current situation and health advice to the public This is the first local outbreak of DF of this scale since the major local outbreak in Ma Wan in 2002. Two distinct sources have been identified.With the implementation of prompt, continuous and intensive anti-mosquito operations, the number of new cases has been decreasing markedly in the past two weeks, with the date of onset of the last case on August 20, 2018 in Lion Rock Park/ Wong Tai Sin cluster, and August 28, 2018 in the Cheung Chau cluster. It is essential to continue the intensive anti-mosquito measures in the coming months in all districts to prevent DF from taking root in Hong Kong.

Apart from the Government’s prevention and control measures, the prevention of secondary spread of DF as well as the carrying out of anti-mosquito measures by members of the public are equally important. Members of the public can help in the prevention of DF by taking part in mosquito control actions and adopting personal protective measures against mosquito bites.The following preventive measures should be taken to prevent accumulation of stagnant water and eliminate mosquito breeding sites:

❖ Thoroughly check all gully traps, roof gutters, surface channels and drains to prevent blockage; ❖ Scrub and clean drains and surface channels with an alkaline detergent compound at least once a week to remove any deposited mosquito eggs; ❖ Properly dispose of refuse, such as soft drink cans, empty bottles and boxes, in covered litter containers; ❖ Completely change the water of flowers and plants at least once a week.; the use of saucers should be avoided if possible; ❖ Level irregular ground surfaces before the rainy season; and ❖ Avoid staying in shrubby areas.

Members of the public are also advised to protect themselves from mosquito bite by taking the following measures:

❖ Wear loose, light–coloured, long-sleeved tops and trousers, and apply effective mosquito repellent containing DEET to exposed parts of the body and clothing; ❖ Use mosquito screens or bed nets when the room is not air-conditioned; and ❖ Place anti-mosquito devices near entrances such as windows and doors to prevent mosquitoes from entering indoor.

People who reside in or visit Cheung Chau are advised to apply insect repellent during their stay and continue applying for 14 days after their last day of stay to prevent infection or secondary spread.

More information on preventive measures could be found in the website of CHP at http://www.chp.gov.hk/en/content/9/24/19.html. For the latest situation of the DF outbreak, please visit the designated DF website at https://www.chp.gov.hk/en/features/38847.html.

Tuberculosis among Educational Institutions in Hong Kong in 2017 Reported by Dr WS LAW, Senior Medical and Health Officer, and Dr CK CHAN, Consultant Chest Physician i/c, Tuberculosis and Chest Service, Public Health Services Branch, CHP.

Introduction Despite a marked decrease in notification rate in the past few decades, tuberculosis (TB) is still a relatively common disease in Hong Kong. A total of 4 306 TB cases (provisional figure) were notified to the Department of Health (DH) in 2017, corresponding to a notification rate of 58.27 per 100 000 population.The number of TB cases notified to DH among subjects in the usual school age of three to 24 was 283 (6.6% of all notifications) in 20171, which represents a 38.1% reduction compared to the corresponding figure of 457 in 2008. Being an airborne infectious disease, clustering of TB cases in educational institutions does occur from time to time, as in other congregational settings2-4.This article gives a brief overview of clustering of TB cases in the school setting in Hong Kong in 2017. Summary data on the epidemiological pattern and molecular characterisation of the various school clusters will be presented.

TB Cluster in the School Setting in 2017 A total of 15 clusters of TB cases were reported among educational institutions in 2017. The majority (13 clusters, 86.7%) occurred in secondary and post-secondary schools (Table 1). The cluster size ranged from two to 15 cases, with a median of four cases (data as of May 31, 2018). Of the 15 primary cases, 12 (80.0%) were students. The rest were either teaching or supporting staff.

COMMUNICABLE DISEASES WATCH 78 Aug 26 - Sep 8 2018 WEEKS 35 - 36 VOL 15 ISSUE NO 18 Table 1 - Characteristics of clusters among educational institutions in 2017.

School Cluster 1 2 3 4 5

Primary case Student Student Student Student Student

Institution Secondary School Post-Secondary school Secondary School Secondary School Secondary School

Cluster size 3 4 15 5 4

Number with a positive sputum and/ or other specimen culture 3 4 8 4 3

Indistinguishable Indistinguishable Indistinguishable Indistinguishable Indistinguishable VNTR result* VNTR pattern 2 VNTR pattern 2 VNTR pattern 3 Different VNTR pattern 1 Different VNTR pattern 2 VNTR pattern Different VNTR pattern 1 VNTR pattern

School Cluster 6 7 8 9 10 11 12 13 14 15

Primary case Student Student Student Student Student Student Student Staff Staff Staff

Post- Post- Secondary Post- Post- Post- Post- Primary Secondary Institution Secondary Secondary School Secondary Secondary Secondary Secondary Kindergarten school School school school school school school school

Cluster size 7 4 3 6 4 3 3 2 2 2

Number with a positive sputum 2 2 3 5 3 3 3 1 0 1 and/ or other specimen culture

Different Different Different Different Different Different Different VNTR result* VNTR VNTR VNTR VNTR VNTR VNTR VNTR NA NA NA pattern pattern pattern pattern pattern pattern pattern *VNTR: molecular typing with variable number tandem repeat; NA:VNTR result not available as there were less than two culture positive cases in that cluster

Molecular characterisation To establish any possible bacteriological link between the cases in individual school clusters, molecular typing with variable number tandem repeat (VNTR) on positive isolates from the microbiologically confirmed cases were retrospectively performed by the TB laboratory of the Public Health Laboratory Centre using standard procedures5. An indistinguishable VNTR pattern was detected among some or all of the bacteriologically confirmed TB cases in five clusters (Cluster 1 to 5), suggesting that at least some of the cases in these individual clusters were genotypically related and that there had been transmission between the cases(Table 1). On the other hand, different VNTR patterns were detected among the bacteriologically confirmed TB cases in seven clusters (Cluster 6 to 12), suggesting that the cases in these individual clusters were unlinked and were more likely to be part of a larger network of community transmissions. Molecular characterisation to establish any bacteriological link between the cases in individual cluster was not possible for the remaining three clusters (Cluster 13 to 15) as there were fewer than two culture-confirmed tuberculosis cases.

Characteristics of primary cases among the five clusters with cases that were genotypically linked The epidemiological and clinical presentations of the primary cases among the five clusters with cases that were genotypically linked were shown in Table 2.The primary case and the secondary cases in these five clusters either studied in the same class or were epidemiologically linked in other school activities. All of them were students. Majority were studying in secondary schools (80%) and had prolonged cough for two months or more (80%). All primary cases had a positive sputum and/or bronchial aspirate smear for acid fast . One primary case (20.0%) had bacillary drug resistance to streptomycin. Four (80.0%) primary cases had cavitary lung disease on initial chest radiograph. The extent of lung parenchymal lesion was moderate in two (40.0%) and extensive in two (40.0%) primary cases. None of the primary cases had a family history of TB within the past two years prior to the diagnosis of TB.

Discussion A substantial number of TB cases still occurred among subjects in the usual school age of three to 24 in 2017, although the situation has significantly improved as compared with a decade ago.While clustering of TB cases in the school setting occurred, molecular typing, supplemented with standard contact investigation, showed that the TB cases in the individual clusters were possibly linked in less than half of the clusters. Among the latter, delayed presentation of the primary cases, as exemplified by a rather long median interval of symptoms of two month before TB was diagnosed, a high proportion with a positive sputum and/ or bronchial aspirate smear for acid fast bacilli, and a high proportion with moderate to extensive cavitary lung disease on initial chest radiograph, probably accounted for the TB spread in these clusters. The school environment might have been one of the predisposing factors, as the close proximity of students in small congested classrooms might facilitate transmission of TB, especially if ventilation was insufficient. Early identification of TB cases and prompt initiation of anti-TB treatment remain the mainstay of TB control among educational institutions, while mass contact screening and post-exposure chemoprophylaxis for COMMUNICABLE DISEASES WATCH 79 Aug 26 - Sep 8 2018 WEEKS 35 - 36 VOL 15 ISSUE NO 18 exposed contacts documented to have acquired the infection might play a supplementary role6. To facilitate early diagnosis and timely treatment of this airborne infectious disease at the source, it is important to promote awareness of TB in schools, the general community as well as the healthcare sector, and to reduce social stigma against TB patients7.

Table 2 - Characteristics of primary cases among the five clusters with cases that were genotypically linked.

School Cluster 1 2 3 4 5

Primary case Student Student Student Student Student

Institution Secondary School Post-Secondary school Secondary School Secondary School Secondary School

Sex F M M M M

Age 16 19 16 17 17

Cough, haemoptysis, Symptoms Cough Cough, fever fever, weight loss Cough, fever Cough, weight loss

Duration of symptoms 2 months 3 weeks 4 months 2 months 3 months

CXR extent* II III III II II

Cavitary lesion Yes Yes Yes Yes No

Sputum or BAL smear† + + + + + Resistant to S, # Sensitivity test Favourable ST sensitive to HRE Favourable ST Favourable ST Favourable ST

Contact history of TB No No No No No

Epidemiological link with Yes Yes Yes Yes Yes secondary cases

Number of secondary cases 2 3 14 4 3 *Extent I: total radiographic extent smaller than the equivalent of right upper lobe; extent II: total radiographic extent greater than the equivalent of right upper lobe but smaller than the equivalent of right lung; extent III: total radiographic extent greater than the equivalent of right lung †BAL: Bronchial aveolar lavage #ST: sensitivity test; S: streptomycin; H: isoniazid; R: rifampicin; E: ethambutol

References 1Tu b e rc u l o s i s i n t h e s c h o o l s e t t i n g i n H o n g Ko n g i n 2 0 1 7 . Available at http://www.info.gov.hk/tb_chest//doc/TB_in_school_setting_Web_page_June_2018-ENG.pdf. Accessed on September 3, 2018. 2Epidemiology of a Tuberculosis Outbreak in a South Carolina Junior High School. EJ Sacks, ER Brenner, DC. Breeden et al.Am J Public Health 1985; 75:361-5. 3Tu b e rc u l o s i s O u t b re a k i n a P r i m a r y S c h o o l , M i l a n , I t a l y. M F a c c i n i , L R C o d e c a s a , G C i c o n a l i e t a l . E m e r g I n f e c t D i s 2 0 1 3 ; 1 9 ( 3 ) : 4 8 5 - 7 . 4Concurrent Outbreaks of Tuberculosis in a School and the Wider Community in Macau. KH Chou, KM Kam, SK Ieong, et al. J Pediatric Infect Dis Soc 2015; 4(4): 359–62. 5Proposal for Standardization of Optimized Mycobacterial Interspersed Repetitive Unit-Variable-Number Tandem Repeat Typing of Mycobacterium tuberculosis. P Supply, C Allix, S Lesjean et al. J Clin Microbiol 2006; 44(12): 4498–510. 6Outbreak of Pulmonary Tuberculosis in a Chinese High School, 2009–2010.Y Fang, L Zhang, C Tu et al. J Epidemiol 2013;23(4):307-12. 7Tuberculosis stigma as a social determinant of health: a systematic mapping review of research in low incidence countries. GM Craig,A. Daftary, N. Engel et al. Int J Infect Dis 2017; 56: 90-100.

NEWS IN BRIEF

A local case of Streptococcus suis infection On August 29, 2018, the Centre for Health Protection (CHP) recorded a case of Streptococcus suis infection affecting a 98-year-old woman with underlying illnesses. She presented with fever, vomiting and diarrhoea on August 25, and was admitted to a public hospital on August 27. Her blood culture collected on August 27 yielded Streptococcus suis and she was treated with antibiotics. Her condition remained stable. She had no recent travel history, and had no high risk exposure or recent wound. Her home contact was asymptomatic.

Four sporadic cases of necrotising fasciitis caused by Vibrio vulnificus From August 29 to September 4, 2018, CHP recorded four sporadic cases of necrotising fasciitis caused by Vibrio vulnificus.The first case was an 82-year-old female with underlying illnesses. She presented with fever and left forearm painful swelling on August 27, and was admitted to a public hospital on the same day. The clinical diagnosis was necrotising fasciitis. Wound debridement and left upper limb amputation was done on August 27 and 28 respectively. Necrotic tissue collected from her left forearm on August 27 grew Vibrio vulnificus. She was treated with antibiotics and remained in stable condition. The patient recalled history of a prick injury resulting in bleeding by an unknown sharp object in another person’s shopping bag while walking in a wet market in Wong Tai Sin on August 26.

COMMUNICABLE DISEASES WATCH 80 Aug 26 - Sep 8 2018 WEEKS 35 - 36 VOL 15 ISSUE NO 18 The second case was a 58-year-old male with good past health who presented with fever and right arm painful swelling on August 29. He was admitted to a public hospital on the same day and the clinical diagnosis was necrotising fasciitis.Wound debridement was performed on August 29 and right arm fascial fluid collected during the operation grew Vibrio vulnificus. He was treated with antibiotics and remained in stable condition.The patient had bought a fish from another wet market in Wong Tai Sin on August 28 and prepared it at home. He did not report recent injury or wound.

The third case was an 85-year-old woman with underlying illnesses. She presented with fever, left ankle swelling and pain on August 30, and was admitted to a public hospital on August 31. She developed septic shock and was transferred to the intensive care unit for further management on the same day. The clinical diagnosis was necrotising fasciitis and wound debridement was performed on September 1. Blood culture and left leg tissue collected on August 31 and September 1 respectively grew Vibrio vulnificus. She was treated with antibiotics and her condition remained stable. She did not report recent injury or wound.

The fourth case was an 88-year-old woman with underlying illnesses. She swam daily in a beach in Mui Wo and recalled having had sustained a right shin contusion at a friend’s home on August 31. She developed increased pain and swelling over her right leg on September 3 and was admitted to a public hospital on the same day.The clinical diagnosis was necrotising fasciitis and right above knee amputation was performed on September 5. Her right leg wound swab collected on September 3 grew Vibrio vulnificus. She was treated with antibiotics and her condition was critical.

All four patients had no recent travel history and their home contacts were asymptomatic. Investigation so far did not identify epidemiological linkage among the cases.

Ad Hoc Infectious Disease Forum: An Update on Dengue Fever An ad hoc Infectious Disease (ID) Forum was held on August 31, 2018 in view of the rise in local dengue fever cases in Hong Kong. Speakers from the Surveillance and Epidemiology Branch of CHP, adult and paediatric infectious disease specialists and representative from the Hospital Authority (HA) shared with healthcare workers about the current situation in Hong Kong and reminded them of the warning to be alert of and gave update on the latest diagnosis and management logistics in HA.

Participation was keen with up to 180 frontline clinical staff, DH colleagues and HA senior Photo - An ad hoc ID Forum was held on August executives, including hospital chief executives and department chiefs of service joining the 31, 2018. A total of 180 participants attended the forum and it was well received by the forum. participants. During the talks, participants were informed of the current two separate clusters of cases identified. Enhanced measures including prevention, control, and active case identification were shared. Presentations also highlighted the management in pregnant women and the difficulty in differentiating from pre-eclampsia.

Real clinical cases with illustrating photos made a strong impression on the audience to have high index of suspicion in febrile patients with compatible clinical features. Lastly, all were reassured that there were updated protocols and contingency plans to cater for potential upsurge. Blood donors’ management was also explained.

A sporadic case of psittacosis On September 7, 2018, CHP recorded a sporadic case of psittacosis affecting a 68-year-old woman with underlying illnesses. She had presented with fever, cough, difficulty breathing, muscle pain and headache since August 27. She attended the Accident and Emergency Department of a public hospital on August 31 and was admitted for management on the same day. Her chest X-ray showed left sided consolidation and the diagnosis was pneumonia. Her nasopharyngeal aspirate collected on September 1 was tested positive for Chlamydophila psittaci DNA by polymerase chain reaction. She was treated with antibiotics. Her condition remained stable and was discharged on September 8. She lives with her husband, daughter and son and has travelled to Huizhou from August 22 to 23. She did not recall any direct contact with birds or their excreta there and elsewhere in Hong Kong during the incubation period. Her home contacts and travel collaterals were asymptomatic.

CA-MRSA cases in August 2018 In August 2018, CHP recorded a total of 115 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 60 males and 55 females with ages ranging from two years to 83 years (median: 36 years). Among them, there were 85 Chinese, 9 Filipinos, 5 Caucasian, 3 Indian, 3 Pakistani, 1 Bangladeshi, 1 Korean, 1 Nepalese, and 7 of unknown ethnicity. All cases presented with uncomplicated skin and soft tissue infections.

Eight household clusters, with each affecting two persons, were identified. No cases involving healthcare worker were reported during this period.

Scarlet fever update (August 1, 2018 – August 31, 2018) Scarlet fever activity further decreased in August. CHP recorded 69 cases of scarlet fever in August as compared with 153 cases in July. The cases recorded in August included 37 males and 32 females aged between 18 months and 32 years (median: five years).There was one institutional cluster occurring in a kindergarten-cum-child care centre, affecting two children. No fatal cases were reported in August.

COMMUNICABLE DISEASES WATCH 81 Sep 9 - Sep 22 2018 WEEKS 37 - 38 VOL 15 ISSUE NO 19

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS 2018/19 New Initiatives to Promote Seasonal Influenza Vaccination Among School Children Reported by Dr Emily MAN, Medical and Health Officer, Programme Management and Professional Development Branch, CHP

In 2017/18 winter influenza season, 600 Influenza-like illness (ILI) outbreaks were recorded, which exceeded the numbers recorded in major flu seasons in previous five years. Most ILI outbreaks occurred in schools, including kindergartens/child care centres (KG/CCC) and primary schools.Weekly influenza admission rates in public hospitals were highest among young children 0-5 years (8.63 per 10 000 population), followed by elderly >=65 years (4.25) & children 6-11 years (3.81). While severe cases mainly affected the elderly, 20 cases of severe paediatric influenza-associated complication/ death (including two deaths) were recorded, and 19 (95%) of whom had not received the 2017/18 seasonal influenza vaccine.

To promote Seasonal Influenza Vaccination (SIV) among school children, in 2018/19, the Government launches the School Outreach Vaccination Pilot Programme (Pilot Programme) and the Enhanced Vaccination Subsidy Scheme Outreach Vaccination (Enhanced VSS), in addition to continuation of Vaccination Subsidy Scheme (VSS) in private clinics.

Under the Pilot Programme, primary school children will receive free SIV at participating schools. There are two types of outreach teams, namely Department of Health Outreach Team (DH mode) and Public-Private-Partnership Outreach Team (PPP mode). For both modes, the Department of Health (DH) will arrange procurement and delivery of vaccines, collection of unused vaccines and clinical waste, as well as administrative support. Vaccination will be performed by outreach teams either from DH or private doctors participating in PPP mode. An injection fee HKD$70 per dose will be provided for PPP doctors. A total of 184 primary schools, including 35 DH mode and 149 PPP mode, will join the Pilot Programme.

Under Enhanced VSS, primary schools, kindergartens, kindergarten-cum-child care centres, child care centres and primary section of special schools can invite enrolled Enhanced VSS doctors to provide free SIV service for students who are Hong Kong residents.The enrolled Enhanced VSS doctors are responsible for procurement and delivery of vaccines, administration of vaccines, collection of unused vaccines and clinical waste as well as administrative support. Currently, there are more than 90 doctors on the “List of Doctors Providing Enhanced VSS Outreach Vaccination at School-setting”.Their names and information are available on Centre for Health Protection (CHP) website.

Besides the above new initiatives, children between the age of six months and less than 12 years or primary school students (Hong Kong residents) continue to be eligible for Vaccination Subsidy Scheme (VSS) in private clinics. The subsidy level for seasonal influenza vaccination has been increased to HKD$210 per dose. Participating doctors may impose extra charges. Charges and details are listed on CHP website.

For children between six months and less than 12 years old, or 12 years old or above but attending a primary school in Hong Kong; and come from families receiving Comprehensive Social Security Assistance or holders of valid Certificate for Waiver of Medical Charges issued by the Social Welfare Department, under Government Vaccination Programme, they can get free SIV in Maternal and Child Health Centres (MCHC) or Student Health Service Centres (SHSC) of DH. Children from six months to under six years old or attending kindergartens or child care centres can get free SIV in MCHC, while children from six years to under 12 years old or age 12 or above but attending primary schools can get free SIV in SHSC.

DH will continue to work closely with health care sectors, community partners and education sectors to promote vaccination. DH will publicise through various media activities including TV and radio, websites/ facebook, briefing session, specialist interviews, videos, articles to newspapers and magazines, leaflets and posters, advertisements, as well as health education hotline.

For latest information, please visit following webpage for details: https://www.chp.gov.hk/en/features/17980.html. You may also contact vaccination office hotline at 2125 2125.

COMMUNICABLE DISEASES WATCH 82 Sep 9 - Sep 22 2018 WEEKS 37 - 38 VOL 15 ISSUE NO 19 Review of grayanotoxin poisoning in Hong Kong, 2012-2018 Reported by Dr Albert LAM and Dr Ambrose WONG, Senior Medical and Health Officer, Field Epidemiology Training Programme, Surveillance and Epidemiology Branch, CHP. Grayanotoxin poisoning is caused by ingestion of plants or products containing grayanotoxins which are derived from plants belonging to the Ericaceae family, including rhododendrons. Grayanotoxin poisoning caused by consumption of honey is called “mad honey poisoning” and honey containing grayanotoxins often has bitter taste. Grayanotoxin poisoning is well-known in the Black Sea area of Turkey and Nepal but has also been reported in other countries. Grayanotoxins are neurotoxins which can affect nerves and muscles. Symptoms of grayanotoxin poisoning include nausea, vomiting, diarrhoea, dizziness, weakness, excessive perspiration, hypersalivation and paraesthesia shortly after ingestion, usually within 20 minutes to three hours. In severe cases, hypotension, bradycardia or shock may occur1,2.

Food poisoning is a statutory notifiable disease in Hong Kong. Medical practitioners are required to report suspected or confirmed cases to the Centre for Health Protection (CHP) of the Department of Health (DH). Grayanotoxin poisoning is a type of biochemical food poisoning that was occasionally reported in Hong Kong. In this article, we reviewed grayanotoxin poisoning cases recorded by CHP from January 2012 to September 24, 2018.

During the study period, a total of seven grayanotoxin poisoning cases affecting nine persons were recorded. The annual number of reported cases ranged from zero to three, with each case affecting one to three persons (median: one person) (Figure 1). The cases were reported almost all over Figure 1 - Grayanotoxin poisoning cases/ persons affected the year with no seasonal trend observed. recorded from 2012 to 2018 (as of September 24, 2018).

Fifty-six percent of the affected persons were male. Patient’s ages ranged from 30 to 66 years with a median of 49 years. The most common presenting symptoms were systemic or neurological in nature including dizziness (7, 78%), numbness (5, 56%) and sweating (5, 56%). Gastrointestinal symptoms such as vomiting (4, 44%), abdominal pain (3, 33%), nausea (3, 33%) and diarrhoea (1, 11%) were less commonly reported. The patients developed symptoms from five minutes to two hours (median: one hour) after consumption of the incriminated food item. All affected persons had hypotension, bradycardia and required hospital admission. Two required admission to Coronary Care Unit and one required admission to Intensive Care Unit for management. There was no fatality recorded.

The diagnosis of grayanotoxin poisoning is based on food consumption history, presenting symptoms, and detection of grayanotoxin in patient’s clinical specimen and/ or in food or plant sample. Among the nine affected persons, eight (88.9%) of them had urine sample tested positive for grayanotoxin and one had no clinical sample available for testing. Among the seven cases, honey or plant samples obtained from the patients were all tested positive for grayanotoxin.

Among the seven cases, six of them consumed honey bought (1, 16.7%) or given by friends (5, 83.3%) from Nepal. One affected person consumed wild picked flower (杜鵑花) in Hong Kong.

To avoid grayanotoxin poisoning, members of the public are advised to buy honey from reliable sources and apiaries; discard honey with a bitter or astringent taste because grayanotoxin-containing honey may cause a burning sensation in the throat; pay special attention to honey from Nepal and the Black Sea region of Turkey as there have been grayanotoxin poisoning cases connected with honey from these areas.

References 1Jansen, S.A., et al., Grayanotoxin poisoning: 'mad honey disease' and beyond. Cardiovasc Toxicol, 2012. 12(3): p. 208-15. 2Chen, S.P., et al., Mad honey poisoning mimicking acute myocardial infarction. Hong Kong Med J, 2013. 19(4): p. 354-6.

NEWS IN BRIEF

A sporadic case of listeriosis On September 12, 2018, the Centre for Health Protection (CHP) recorded a sporadic case of listeriosis affecting a 75-year- old man with end-stage renal failure on continuous ambulatory peritoneal dialysis. He presented with fever, abdominal pain, turbid peritoneal fluid and diarrhoea on September 8, and was admitted to a public hospital on the same day. His peritoneal dialysate collected on September 8 yielded Listeria monocytogenes. He was treated with antibiotics and his condition was stable. He had no recent travel history except for a day trip to Shenzhen on September 5 and he denied high risk food consumption during the incubation period. His home contacts were asymptomatic.

COMMUNICABLE DISEASES WATCH 83 Sep 9 - Sep 22 2018 WEEKS 37 - 38 VOL 15 ISSUE NO 19

A probable case of sporadic Creutzfeldt-Jakob disease On September 13, 2018, CHP recorded a probable case of sporadic Creutzfeldt-Jakob disease (CJD) affecting a 65 year-old man with underlying illness. He presented with mental dullness and left upper limb twitching on July 13, and had hospital admission for convulsion in mid-July and early August respectively. He developed convulsion again on August 16 and was admitted to a public hospital on the same day. He was noted to have rapidly progressive dementia, pyramidal signs and akinetic mutism. Investigations showed that his cerebrospinal fluid was tested positive for 14-3-3 protein and his electroencephalography findings were compatible with CJD. He was transferred to another public hospital for further management on August 27 and his condition was stable at the time of reporting. No risk factors for either iatrogenic or variant CJD were identified. He was classified as a probable case of sporadic CJD.

A sporadic local case of Streptococcus suis infection On September 13, 2018, CHP recorded a case of Streptococcus suis infection affecting a 77-year-old female with underlying illnesses. She presented with fever, muscle pain and dizziness on September 11, and was admitted to a public hospital on the same day. Her blood culture collected on September 12 yielded Streptococcus suis and she was treated with antibiotics. Her condition remained stable. She handled raw pork at home daily but could not recall any recent wound or injury. She had no recent travel history. Her home contacts were asymptomatic.

Three domestic clusters of pertussis From September 7 to 21, 2018, CHP recorded three domestic clusters of pertussis.

The first cluster affected a two-month-old baby boy and his 33-year-old father. The baby had developed cough since August 24, 2018. He attended the Accident and Emergency Department of a public hospital and was subsequently admitted to paediatric ward on September 4. His pernasal swab collected on September 5 was tested positive for Bordetella pertussis. He was treated with antibiotics. He remained stable all along and was discharged on September 11. He received his first dose of diphtheria, tetanus, acellular pertussis and inactivated poliovirus vaccine (DTaP-IPV) on August 24 just before symptom onset.

Epidemiological investigation revealed that his father had developed cough since September 10. His pernasal swab collected on September 10 was tested positive for Bordetella pertussis. He was treated with antibiotics. His condition was stable. He was not sure about his vaccination history. Both patients had no travel history during the incubation period.

The second cluster affected a 52-year-old man and his 14-year-old son.The man with underlying illnesses had presented with cough and inspiratory whoop since August 17. He consulted private doctors, attended an outpatient clinic and the Accident and Emergency Department of a public hospital from August to September. His nasopharyngeal swab collected on September 11 was tested positive for Bordetella pertussis. He was treated with antibiotics and his condition was stable. He was not sure about his vaccination history.

Epidemiological investigation revealed that his son had developed cough since September 9. He attended the outpatient clinic of a public hospital on September 14. His nasopharyngeal swab collected on September 14 was tested positive for Bordetella pertussis. He was treated with antibiotics and his condition was stable. He had completed 6 doses of DTaP-IPV according to the Hong Kong Childhood Immunisation Programme (HKCIP). Both patients had no travel history during the incubation period.

The third cluster affected a two-month-old baby girl and her four-year-old brother. The baby girl had developed cough since August 24, 2018. She attended the Accident and Emergency Department of a public hospital and was subsequently admitted to the paediatric ward on September 9. Her pernasal swab collected on September 11 was tested positive for Bordetella pertussis. She was treated with antibiotics. She remained stable all along and was discharged on September 13. The girl had not yet received her first dose of DTaP-IPV.

Epidemiological investigation revealed that her elder brother had developed cough since September 15. His pernasal swab collected on September 18 was tested positive for Bordetella pertussis. He was treated with antibiotics. His condition was stable. He had DTaP-IPV vaccine according to HKCIP. Both patients had travelled to Fujian, China during incubation period.

Two local cases of human myiasis From May 1 to September 24, CHP recorded two cases of human myiasis. The first case was a 65-year-old male with underlying illnesses. He was a resident of a residential care home for the elderly (RCHE) in Sham Shui Po with no recent travel history. He presented with fever and left facial swelling on June 12, and was admitted to a public hospital on the same day. Physical examination of his oral cavity revealed extensive palatal ulcers with worms and dental caries. Computer tomography of the face and neck showed left . The clinical diagnoses were dental abscess and oral myiasis. He was treated with antibiotics. His condition remained stable and he was discharged on June 20.

The second case was an 83-year-old woman with underlying illnesses. She was also a resident of a RCHE in Tsuen Wan with no recent travel history. She presented with gum bleeding on September 3 and was admitted to a public hospital on the same day. Physical examination found a large ulcer and worms in her oral cavity.The clinical diagnosis was oral myiasis and she was treated with antibiotics. She passed away on September 7 due to other illness.

The worms removed from both cases were confirmed to be larvae of Chrysomya bezziana. Advice on wound care and environmental hygiene was given to the RCHEs concerned during site visit.There were no other myiasis cases identified in the two RCHEs and investigations so far did not identify epidemiological linkage between these two cases.

COMMUNICABLE DISEASES WATCH 84 Sep 23 - Oct 6 2018 WEEKS 39 - 40 VOL 15 ISSUE NO 20

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Review of hepatitis E infection in Hong Kong Reported by Dr Jess YIM, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Facts on hepatitis E Hepatitis E is a liver disease caused by infection of the hepatitis E virus (HEV). HEV is a single-stranded RNA virus and has at least four genotypes, namely, genotypes 1 to 4. While genotypes 1 and 2 viruses have only been found in humans, genotypes 3 and 4 viruses circulate in several animals (including pigs, wild boar and deer) and occasionally infect humans1.

Foodborne transmission of HEV can result from ingestion of undercooked meat or meat products produced from infected animals. For instance, HEV has been detected in pig livers. Besides, HEV is also transmitted through the faecal-oral route due to faecal contamination of drinking water. Other rare transmission routes identified include transfusion of infected blood products, organ transplant and vertical transmission from a pregnant woman to her foetus.

The incubation period following exposure to HEV ranges from two to ten weeks, with a mean of five to six weeks1. The symptoms of HEV infection typically last between one and six weeks and are often indistinguishable from those of other acute liver diseases. Children often have either no symptoms or only a mild illness without jaundice that goes undiagnosed. Typical signs and symptoms of HEV infection include fever, reduced appetite, nausea, vomiting, abdominal pain, skin itchiness, skin rash, joint pain, jaundice, dark urine, pale stool, and an enlarged and tender liver. In rare cases, acute HEV infection results in fulminant hepatitis which can be fatal. Fulminant hepatitis occurs more frequently in pregnant women with HEV infection. Those in the second or third trimester are at an increased risk of acute liver failure, fetal loss and mortality. Case fatality rates as high as 20% to 25% have been reported among pregnant women in their third trimester1. Cases of chronic HEV infection have been reported in immunosuppressed people, particularly organ transplant recipients on immunosuppressive drugs.

According to the World Health Organization, there are an estimated 20 million HEV infections worldwide, leading to an estimated 3.3 million symptomatic cases of HEV infection every year1. HEV infections are most common in East and South Asia.

In Hong Kong, viral hepatitis (including acute hepatitis caused by hepatitis E) is a notifiable disease under the Prevention and Control of Disease Ordinance (Cap 599). From 2013 to 2018 (as of September 30), the Centre for Health Protection (CHP) of the Department of Health recorded a total of 461 confirmed cases of acute hepatitis caused by HEV. From 2013 to 2017, the annual number of cases ranged from 64 to 96 (Figure 1). In 2018, 34 cases Figure 1 - Annual number of acute hepatitis E cases in Hong Kong, 2013-2018 (*provisional figure as of September 30, 2018). have been recorded as of September 30.

The 461 cases involved 288 males and 173 females, with ages ranging from 15 to 96 years (median: 56 years). The majority of patients were Chinese (420, 91.1%). Most cases (377, 81.8%) were locally acquired infections, while 29 cases (6.3%) were imported infections.The places of infection outside Hong Kong included Mainland China (20 cases), India (two cases), Indonesia

COMMUNICABLE DISEASES WATCH 85 Sep 23 - Oct 6 2018 WEEKS 39 - 40 VOL 15 ISSUE NO 20 (one case), Korea (one case), Nepal (one case), Pakistan (one case), the Philippines (one case), Thailand (one case) and the United Kingdom (one case). The places of infection of the remaining 55 cases (11.9%) could not be determined as the patients had stayed both in and outside Hong Kong during the incubation period. From 2013 to 2017, more cases were recorded from January to April (Figure 2).

The most common clinical presentation was tea-coloured urine (348, 75.5%), followed by jaundice (313, 67.9%), anorexia (241, 52.3%), nausea (159, 34.5%) and abdominal pain (156, 33.8%). Three hundred and ninety-nine patients (86.6%) required hospitalisation with a median length of stay of seven days. Fifteen (3.3%) patients developed liver failure. A total of nine fatal cases were recorded, giving a case Figure 2 - Seasonality of hepatitis E infection in Hong Kong, fatality rate of 2.0%.The ages of the deceased patients ranged from 49 2013-2017. to 81 years (median: 74 years). Among the fatal cases, eight were known to have underlying illnesses. One case was a pregnant woman in her third trimester of gestation at the time of diagnosis. She recovered uneventfully without developing any complications.

Epidemiological investigations revealed that 252 (54.7%) and 132 (28.6%) patients reported consumption of pork and pig liver during the incubation period, respectively. Among those who consumed pig liver, 19 and seven consumed it with hotpot and , respectively. Besides, 133 (28.9%) patients reported consumption of shellfish during the incubation period. The commonest shellfish consumed was oyster (68, 51.1%), followed by clams (62, 46.6%) and (22, 16.5%).Among those who had consumed oyster, nine reported consuming it raw.

One case recorded in August 2018 acquired the infection from organ transplant. The incident involved a single deceased donor whose organs (heart, lungs, liver and two kidneys) had been donated to five recipients in February 2018. One of the recipients, the liver transplant recipient, was found to have deranged liver function during a follow-up in June and his serum was subsequently tested positive for anti-HEV immunoglobulin M (IgM). Epidemiological investigations revealed that the patient likely acquired HEV infection through liver transplant. Subsequent laboratory investigations confirmed that the donor and the other four recipients also had HEV infection. Among the five recipients, four remained in stable condition all along and had recovered from the infection while the lung recipient had passed away due to other causes.

Vaccine for hepatitis E is not available in Hong Kong. The mainstay of prevention of hepatitis E is maintaining good personal hygiene, especially hand hygiene, and adherence to food and water safety. The risk of hepatitis E infection can be reduced by adopting the Five Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases, for example:

✦ Maintain hygienic practices such as hand washing with soap and water, particularly before handling food or eating, and after using the toilet or handling vomitus or faecal matter; ✦ Obtain drinking water from the mains and it before consumption; ✦ Avoid consumption of water and ice of unknown purity; ✦ Purchase fresh food from reliable sources. Do not patronise illegal hawkers; ✦ Clean and wash food thoroughly; ✦ Cook food, especially (e.g. shellfish), pork and pig offal, thoroughly before consumption. Avoid raw food or undercooked food; and ✦ Use separate chopsticks for handling raw food and cooked food when having hotpot.

References 1World Health Organization (2018) Hepatitis E. Available at: http://www.who.int/news-room/fact-sheets/detail/hepatitis-e, accessed on October 7, 2018.

COMMUNICABLE DISEASES WATCH 86 Sep 23 - Oct 6 2018 WEEKS 39 - 40 VOL 15 ISSUE NO 20 Review of Leptospirosis in Hong Kong, 2008-2018 Reported by Dr Eric LAM, Medical and Health Officer, Communicable Disease Surveillance and Intelligence Office, Surveillance and Epidemiology Branch, CHP.

Leptospirosis is a zoonotic disease, caused by bacteria of genus Leptospira, which occurs most prevalently in tropical and subtropical regions. The disease can be transmitted to humans through contact of cuts and abrasions of the skin or mucous membranes of the eyes, nose and mouth with water or soil contaminated with the urine or other body fluids (except saliva) of infected animals. Consumption of contaminated food or water is also a possible route of transmission. Human-to-human transmission is very rare.

Although many wild and domestic mammals can harbour Leptospira, rodents are considered to be the major source of human infection. The disease is often associated with outdoor water sports such as swimming, wading, kayaking, and rafting in contaminated lakes and rivers. In addition, some occupations pose an increased risk of exposure to Leptospira, such as farmers, , sewer workers, fish workers and slaughterhouse workers, etc. Outbreaks of leptospirosis have been reported in some countries following natural disasters such as flooding, when people had a higher chance of exposure to contaminated water.

The incubation period of leptospirosis is usually five to 14 days, with a range of two to 30 days. Infection with Leptospira can cause mild and non-specific symptoms such as fever, headache, chills, myalgia, abdominal pain, diarrhoea and vomiting. Leptospirosis can be treated with antibiotics. If untreated, the disease could develop into more severe conditions including acute liver and kidney failure with a case fatality rate of 5% to 15%. No human vaccine is currently available in Hong Kong.

Leptospirosis has been a notifiable infectious disease in Hong Kong since July 14, 2008 while it was a voluntarily reportable disease before. Since the disease was made notifiable, up until September 30, 2018, the Centre for Health Protection of the Department of Health has recorded a total of 50 cases of leptospirosis (Figure 1). Over half of the cases (54%) were reported in summer months between June and September (Figure 2) when rainfall was more abundant in Hong Kong and Southeast Asia.

The cases involved 35 males and 15 females, with ages ranging from 15 to 72 years (median: 39.5 years). The majority of the cases presented with non-specific symptoms, including fever (94%), Figure 1 - Number of leptospirosis cases by year, 2008-2018* (*Up to September 30, 2018). headache (46%) and myalgia (40%).About two-third of the cases were found to have hepatic (66%) and renal (64%) impairment. They all recovered after antibiotic treatment.

About half (24 cases, 48 %) were locally acquired infections and another half (25 cases, 50%) were imported infections. The place of infection of the remaining case could not be ascertained as the patient had outdoor recreational activities both in Hong Kong and Malaysia during incubation period.The patients of the imported cases had travelled to Malaysia (13), Laos (5), Thailand (5), Mainland China (3) and the Philippines (1) during the incubation period (one had travelled to both Malaysia and Thailand, and another to both Laos and Figure 2 - Number of leptospirosis cases by month in Thailand). 2008-2018* (*Up to September 30, 2018).

With regard to the possible sources of infection, among the 25 imported cases, almost all (24 cases, 96%) had history of outdoor recreational activities such as hiking, swimming, rafting and diving during incubation period while the remaining case did not report high risk exposure. Among the 24 local cases, the majority (13 cases) had exposure to rodents or stray dogs/cats in the vicinity of their residence or workplace (Figure 3). Four patients engaged in hiking and swimming in the wild in Hong Kong.Three cases were likely related to their occupations which required outdoor work involving contact with contaminated water. The remaining four local cases had no risk factor identified.

COMMUNICABLE DISEASES WATCH 87 Sep 23 - Oct 6 2018 WEEKS 39 - 40 VOL 15 ISSUE NO 20 To prevent infection with leptospirosis, in addition to maintaining personal and environmental hygiene, it is important to avoid contact with animal urine through the following measures:

✦ Avoid swimming in or wading through potentially contaminated water; ✦ Cover skin lesions with waterproof dressings; ✦ Wash and clean wounds; ✦ Avoid touching wild animals; and ✦ Wear protective clothing (such as boots, gloves, spectacles, aprons, masks as and when appropriate) during handling of animals and outdoor working. Figure 3 - Exposure history in local leptospirosis cases, 2008-2018* (*Up to September 30, 2018).

References 1Factsheet Leptospirosis,World Health Organization. Available at: http://www.wpro.who.int/mediacentre/factsheets/fs_13082012_leptospirosis/en/, accessed on October 3, 2018. 2Leptospirosis, US Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/leptospirosis/index.html, accessed on October 3, 2018.

NEWS IN BRIEF

A sporadic case of listeriosis On September 15, 2018, the Centre for Health Protection (CHP) recorded a sporadic case of listeriosis affecting a 78-year-old woman with underlying illnesses. She had presented with fever since September 10 and was admitted to a public hospital on September 12. Her blood specimen collected on September 12 grew Listeria monocytogenes. The clinical diagnosis was sepsis and she was treated with antibiotics. Her condition was stable and she was discharged on September 26. She had consumed sour cream and during the incubation period but could not recall exact brand, date and place of purchase. She had no recent travel history and her household contacts remained asymptomatic. Investigation is on-going.

A possible sporadic case of Creutzfeldt-Jakob disease On September 26, 2018, CHP recorded a possible case of sporadic Creutzfeldt-Jakob disease (CJD) affecting a 68-year-old man with underlying illnesses. He had presented with progressive memory loss, unsteady gait and blurred vision since August 2018 and was admitted to a public hospital on September 24. He was found to have progressive dementia, myoclonus, extrapyramidal dysfunction, rigidity, gait disturbance, dysphasia and visual disturbance. Finding of electroencephalography was atypical for CJD. His condition was stable at the time of reporting. He had no known family history of CJD and no reported risk factors for iatrogenic or variant CJD were identified. He was classified as a possible case of sporadic CJD.

Two sporadic cases of necrotising fasciitis due to Vibrio vulnificus infection On September 27 and 28, 2018, CHP recorded two sporadic cases of necrotising fasciitis due to Vibrio vulnificus infection.The first patient was a 76-year-old male with underlying illnesses. He had presented with fever, left knee and shin pain since September 18. He attended the Accident and Emergency Department of a public hospital on September 25 and was admitted on the same day. The clinical diagnosis was necrotising fasciitis. He was treated with antibiotics, surgical debridement and amputation of left leg. Necrotic tissue collected on September 26 was tested positive for Vibrio vulnificus. He passed away on October 2. He lived in Mainland China before onset of illness and had history of visiting wet market and handling fish at home but did not report any injury. His home contact remained asymptomatic.

The second patient was a 76-year-old male with underlying illnesses. He had presented with fever, left shin pain, swelling, erythema and blistering since September 22. He attended the Accident and Emergency Department of a public hospital on September 26 and was admitted on the same day. The clinical diagnosis was necrotising fasciitis. He was treated with antibiotics and surgical debridement. Pus swab of his left shin wound collected on September 26 was tested positive for Vibrio vulnificus. He required postoperative intensive care. His condition gradually improved and he was currently in stable condition. He had history of visiting wet market and handling fish at home but did not report any injury. He had no recent travel history and his home contact remained asymptomatic.

COMMUNICABLE DISEASES WATCH 88 Oct 7 - Oct 20 2018 WEEKS 41 - 42 VOL 15 ISSUE NO 21

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Update of hand, foot and mouth disease (HFMD) activities in Hong Kong Reported by Dr KONG Wai-chi, Scientific Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Hand, foot and mouth disease (HFMD) is a viral infection commonly seen in children. In Hong Kong, HFMD occurs throughout the year but the disease activity usually peaks between May and July. A smaller peak may also occur from October to December.

The HFMD activity in 2018 has so far followed the usual epidemiological pattern observed in the past two years. The surveillance data of the Centre for Health Protection (CHP) of the Department of Health showed that the HFMD activity in 2018 started to increase in early May, peaked in early June, returned to baseline level in late July. It started to increase again in late September (Figures 1 to 3). Figure 1 - Number of institutional HFMD/herpangina outbreaks recorded by CHP, 2016 to 2018 (as of October 20). During the summer peak in 2018 (from the week ending May 12 to that ending July 28), CHP recorded a total of 208 HFMD/ herpangina institutional outbreaks, as compared with 133 outbreaks recorded in the same period of 2017. The number of outbreaks recorded per week ranged from four to 38 (median: 17). Among the 208 outbreaks, 144 (69.2%) occurred in child care centres/ kindergartens, 54 (26.0%) in primary schools, eight (3.8%) in secondary schools and two (1.0%) in other institutions.A total of 1 382 people were affected and the number of people affected in each outbreak ranged from two to 37 (median: four). The causative agents were identified in 37 (17.8%) outbreaks. These 37 confirmed outbreaks were associated with coxsackievirus A16 (17, 45.9%), enterovirus 71 (EV71) (5, 13.5%), coxsackievirus A6 (3, 8.1%), coxsackievirus A4 (2, 5.4%) and other enteroviruses (10, 27.0%), Figure 2 - Occurrence of HFMD in sentinel child care centres/ respectively. kindergartens, under sentinel surveillance of infectious diseases, 2016 to 2018 (as of October 20). In the current upsurge of HFMD activity since the week ending (Note: Gaps in the graph represented suspension of reports due to school holidays). September 8, 72 outbreaks have been recorded (as of October 20), as compared with 115 outbreaks recorded in the same period in 2017.The number of outbreaks recorded per week ranged from six to 14 (median: 11).Among the 72 outbreaks, 40 (55.6%) occurred in child care centres/ kindergartens, 18 (25.0%) in primary schools, nine (12.5%) in secondary schools and five (6.9%) in other institutions.

As of October 20, a total of 43 cases of EV71 infection have been recorded in 2018. Among them, two and 25 cases were notified before and during the summer peak respectively. Besides, nine cases were notified between the summer peak and the current upsurge. During the current upsurge of HFMD activity since mid-September (as of October 20), a total of seven EV71 cases have been recorded. The 43 Figure 3 - Consultation rate of HFMD syndrome at Accident cases comprised 23 (53.5%) males and 20 (46.5%) females.The patients’ and Emergency Departments in public hospitals under the Hospital Authority, 2016 to 2018 (as of October 20). COMMUNICABLE DISEASES WATCH 89 Oct 7 - Oct 20 2018 WEEKS 41 - 42 VOL 15 ISSUE NO 21 ages ranged from one month to 21 years (median: three years). Two cases developed the complications of encephalitis and meningitis, respectively. No fatal case has been recorded in 2018 so far.

As of October 20, a total of six cases of severe paediatric enterovirus infections (SE) other than EV71 and poliovirus have been recorded in 2018. Among these six cases, five were recorded during the peak season (including four in summer peak and one in recent upsurge).The six cases comprised four males and two females.The patients’ ages ranged from one month to five months (median: two months).All SE cases developed the complication of meningitis. No fatal case has been recorded in 2018 so far.

Currently, the HFMD activity in Hong Kong still remained at an elevated level. CHP will continue to closely monitor the situation. Members of the public are reminded to continue to stay vigilant and observe good personal and environmental hygiene to prevent the disease. The latest surveillance data on HFMD and EV71 are published in the weekly “EV Scan” (http://www.chp.gov.hk/en/guideline1_year/29/134/441/502.html). Further information can be found in the CHP webpage via the link: http://www.chp.gov.hk/en/view_content/16354.html.

Prevention of HFMD Good hygiene practices are the mainstay of prevention: ✦ Maintain good personal hygiene; ✦ Wash hands with liquid soap and water especially: - before touching eyes, nose and mouth; - before eating or handling food; - after touching blister; - after using the toilet; - when hands are contaminated by respiratory secretions e.g. after coughing or sneezing; and - after changing diapers or handling soiled articles; ✦ Cover both the nose and mouth with tissue paper when coughing or sneezing, and wash hands thoroughly afterwards. Dispose of soiled tissue paper in a lidded rubbish bin; ✦ Do not share towels and other personal items; ✦ Regularly clean and disinfect frequently touched surfaces such as furniture, toys and commonly shared items with 1:99 diluted household bleach (mixing one part of 5.25% bleach with 99 parts of water), leave for 15 to 30 minutes, and then rinse with water and keep dry. For metallic surfaces, disinfect with 70% alcohol; ✦ Use absorbent disposable towels to wipe away obvious contaminants such as respiratory secretions, vomitus or excreta, and then disinfect the surface and neighbouring areas with 1:49 diluted household bleach (mixing one part of 5.25% bleach with 49 parts of water), leave for 15 to 30 minutes and then rinse with water and keep dry. For metallic surfaces, disinfect with 70% alcohol; ✦ Avoid group activities when HFMD outbreak occurs in the school or institution. Besides, minimise staff movement and arrange the same group of staff to take care of the same group of children as far as possible; and ✦ Avoid close contact (such as kissing and hugging) with patients.

Updated situation of Ebola Virus Disease in Democratic Republic of Congo Reported by Dr Eric LAM, Medical and Health Officer, Communicable Disease Surveillance and Intelligence Office, Surveillance and Epidemiology Branch, CHP.

On August 1, 2018, less than 10 days after the declaration of the end of the previous Ebola Virus Disease (EVD) outbreak in the Democratic Republic of Congo (DRC), a new EVD outbreak was notified to the World Health Organization (WHO) by the Ministry of Health (MoH) of DRC.The last outbreak in DRC, which began as a cluster of 21 cases of acute haemorrhagic fever in one health zone (Bikoro) in a northwestern province (Equateur) during mid-late May 2018 and affected 54 persons in total, was just declared over on July 24, 20181.

The new outbreak is the tenth EVD outbreak occurring in DRC since the virus was discovered in 1976.When the new outbreak was officially declared on August 1, four cases were confirmed by laboratory testing. Genetic analysis confirmed that the current outbreak was caused by Zaire ebolavirus but it was not linked to the previous outbreak in May-July 20182.

As of October 21, 2018, a total of 238 confirmed and probable cases, including 155 deaths, have been reported, with an increasing trend in weekly number of cases since late September.The cases occurred in two northeastern provinces (North Kivu and Ituri)

COMMUNICABLE DISEASES WATCH 90 Oct 7 - Oct 20 2018 WEEKS 41 - 42 VOL 15 ISSUE NO 21 which border with Rwanda, South Sudan and (Figure 1).The majority of cases have been reported in Beni (104 cases, 44%) and Mabalako (92 cases, 39%) health zones of North Kivu province.Among all the cases, 203 have been confirmed by laboratory testing. A total of 21 healthcare workers were affected3. The epidemic curve and age distribution of the cases are shown in Figures 2 and 3 respectively.

According to the latest risk assessment by WHO, the risk of EVD spread was very high at national and regional levels, but remained low at global level. There are various risk factors for possible spread of EVD beyond the affected areas, including proximity to transportation links with neighbouring countries, compromised security to supporting staff, community resistance to engagement, high population mobility, and other concurrent epidemics including cholera, vaccine-derived polio, etc.

In view of the situation, a meeting of the International Health Regulations Figure 1 - Affected provinces in the latest EVD outbreak in DRC. (Created by Communicable Disease Information (IHR) Emergency Committee was convened by WHO on October 17, 2018. System, CHP) The Committee concluded that a Public Health Emergency of International Concern (PHEIC) should not be declared at the present stage4.WHO has also advised against any international travel or trade restrictions to DRC. However, the Committee emphasised that intensified response activities and ongoing vigilance were critical. Despite the challenges faced by DRC, the Committee has nonetheless commended the rapid and comprehensive response of the DRC government and other non-governmental organisations in supporting surveillance, infection prevention and control, patient care, community engagement and risk communication throughout this disease outbreak3. Figure 2 - Epidemic curve of the latest EVD outbreak in Similar to the response mounted to the EVD outbreak in May-July 2018, DRC, as of October 21, 2018 (n=238). (Source of information:WHO) the MoH of DRC has initiated ring vaccination campaign with the support of WHO in the affected areas since August 8, targeting vaccination for the contacts of infected people, including health care workers. The vaccine used was the recombinant vesicular stomatitis virus–Zaire ebolavirus (rVSV-ZEBOV) vaccine which had been shown to be highly protective against Ebola virus in a major trial led by WHO in Guinea in 20156.As of October 20, 2018, a total of 20 789 people have been vaccinated3.

In Hong Kong, EVD has become a notifiable disease under the disease group of “viral haemorrhagic fever” since 2008. All registered medical practitioners are required to notify the Centre for Health Protection (CHP) of the Department of Health all suspected or confirmed cases of EVD. As of Figure 3 - Confirmed and probable EVD cases by age and sex, DRC, as of October 21, 2018 (n= 235, with 3 cases October 24, 2018, there has been no confirmed case of EVD recorded in the unknown for age/sex). (Source of information:WHO) locality.

All along the Hong Kong Government has been duly vigilant of the latest development concerning EVD around the globe. To prepare for the potential risk imposed by importation of any EVD case and inform the appropriate public health measures in Hong Kong, continuous risk assessment and regular review on the Preparedness and Response Plan for EVD are conducted.

At present there is neither specific treatment nor locally licensed vaccine for EVD yet.To prevent EVD, it is important to observe the following:

✦ Observe good personal and environmental hygiene; ✦ Wash the hands with liquid soap or clean with alcohol-based handrub; ✦ Avoid close contact with feverish or ill persons, and avoid contact with blood or bodily fluids of patients, including items which may have come in contact with an infected person's blood or bodily fluids; ✦ Cook food thoroughly before consumption; and ✦ Avoid contact with animals.

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EVD is caused by Ebolavirus which belongs to the virus family Filoviridae. There are five species within the genus Ebolavirus, but historical outbreaks in Africa were caused by three of them, namely: Bundibugyo ebolavirus, Sudan ebolavirus and Zaire ebolavirus4. The largest outbreak of EVD occurring from 2014 to 2016 in West Africa since its discovery in 1976 was caused by the Zaire ebolavirus. It has resulted in over 28 000 cases and more than 11 000 deaths. The current outbreak in DRC is also caused by the Zaire ebolavirus.

Ebolavirus is transmitted to humans through close contact with blood, secretions, organs or other bodily fluids of its natural host (fruit bats), infected animals or infected humans. The incubation period ranges from two to 21 days. Clinical manifestation is characterised by sudden onset of fever, intense weakness, muscle pain, headache and sore throat, followed by vomiting, diarrhoea, rash, impaired kidney and liver function, and in some cases, internal and external bleeding. There is no specific treatment for the disease. EVD in humans has an average case fatality rate of around 50%.

Sexual transmission has been reported with Ebolavirus. Based on present evidence, WHO recommends that survivors of EVD and their sexual partners should either abstain from all types of sex, or practise safe sex through correct and consistent condom use for 12 months from onset of symptoms or until the semen tests negative twice for Ebolavirus5.

References 1Ebola Situation Report – July 25, 2018,World Health Organization. Available at: http://apps.who.int/iris/bitstream/handle/10665/273348/SITREP_EVD_DRC_20180725-eng.pdf?ua=1, accessed on October 19, 2018. 2Ebola Situation Report – August 7, 2018,World Health Organization. Available at: http://apps.who.int/iris/bitstream/handle/10665/273640/SITREP_EVD_DRC_20180807-eng.pdf?ua=1, accessed on October 19, 2018. 3Ebola Situation Report – October 23, 2018,World Health Organization. Available at: http://apps.who.int/iris/bitstream/handle/10665/275517/SITREP_EVD_DRC_20181023-eng.pdf?ua=1, accessed on October 24, 2018. 4Statement on the October 2018 meeting of the IHR Emergency Committee on the Ebola virus disease outbreak in the Democratic Republic of the Congo. Available at: http://www.who.int/news-room/detail/17-10-2018-statement-on-the-meeting-of-the-ihr-emergency-committee-on-the-ebola-outbreak-in-drc. 5Factsheet Ebola virus disease,World Health Organization. Available at: http://www.who.int/news-room/fact-sheets/detail/ebola-virus-disease, accessed on October 19, 2018. 6Final trial results confirm Ebola vaccine provides high protection against disease, Press Release,World Health Organization. Available at: http://www.who.int/mediacentre/news/releases/2016/ebola-vaccine-results/en/, accessed on October 19, 2018.

NEWS IN BRIEF

Field Epidemiology Training Programme (FETP) training course 2018 The Hong Kong FETP of the Centre for Health Protection (CHP) organised a five-day training course for public health professionals featured epidemiological data analysis during October 8 to 12, 2018. The objective of this course was to equip participants with the knowledge of epidemiological surveillance and outbreak investigation as well as skills of epidemiological data management and analysis with statistical computing. The training course included presentations by the facilitators, practical exercises, interactive case studies and demonstration of interpretation of surveillance and outbreak data. A total of 19 public health professionals attended the course and it was well received by the participants.

A sporadic case of psittacosis On October 12, 2018, CHP recorded a sporadic case of psittacosis affecting a 41-year-old female with unremarkable past health. She had presented with fever, headache, cough, sore throat, runny nose, myalgia, arthralgia and vomiting since September 9 and was admitted to a public hospital on September 14. Her chest X-ray showed left lower zone consolidation and the clinical diagnosis was pneumonia. She was treated with antibiotics and was discharged on September 18. Paired sera collected on September 14 and October 5 showed more than 4-fold rise in Chlamydia antibody titre. Epidemiological investigation revealed that the patient had kept a newly bought parrot at home since mid-August which became sick two days before her symptoms onset. The parrot was subsequently euthanised by a . She had no travel history and her home contacts were asymptomatic.

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Two local cases of listeriosis On October 12, 2018, CHP recorded two local cases of listeriosis affecting a 35-year-old woman and her newborn baby boy. The woman with good past health presented with decreased fetal movement at 35 weeks of gestation on October 9 and was admitted to a public hospital on the same day. Emergency caesarean section was performed for suspected fetal distress. The baby presented with respiratory distress after birth on October 9 and was transferred to neonatal intensive care unit (NICU) for further management. Placental swab from the mother and the blood specimens of the baby grew Listeria monocytogenes. Both the mother and the baby were treated with antibiotics and remained in stable condition.The mother was discharged on October 12 while the baby was still staying in NICU at the time of reporting. Investigation revealed that the mother had consumed during incubation period and further investigation is underway. She had no recent travel history and her other household contacts remained asymptomatic. So far, no other epidemiologically linked cases are identified.

A local sporadic case of leptospirosis On October 19, CHP recorded a local case of leptospirosis affecting a 63-year-old man with underlying illness. He presented with fever, chills, rigor, arthralgia, myalgia and productive cough on September 2, and was admitted to a public hospital on September 10. Blood tests showed acute kidney injury and deranged liver function. He was treated with antibiotics. His condition was stable and he was discharged on September 18. Paired sera taken on September 12 and October 11 showed more than four-fold rise in antibody titre against Leptospira by microscopic agglutination test. Apart from a day trip to Macau on August 30, he had no travel history during the incubation period. He had history of contact with mud and stream water with bare feet in Pat Heung and noticed abrasion over his lower limbs afterwards. He kept three dogs and two cats at his home. His home contacts were asymptomatic.

A domestic cluster of pertussis CHP recorded a domestic cluster of pertussis in mid-October 2018, affecting a three-month-old girl and her three-year-old sister. The three-month-old girl had been admitted to a public hospital on October 13 for paroxysmal cough, post-tussive vomiting, runny nose, shortness of breath and cyanotic spell since September 24. Her nasopharyngeal swab collected on October 13 was tested positive for Bordetella pertussis. She was treated with azithromycin and her condition was stable. She was discharged on October 18.

Contact tracing revealed that patient’s elder sister presented with cough on October 12 and she was referred by CHP to a public hospital for management. Her per-nasal swab collected on October 16 was also tested positive for Bordetella pertussis. She was treated with azithromycin and did not require hospitalisation. Her condition was all along stable.

The two children had no travel history during the incubation period and they both had received Diphtheria,Tetanus, acellular Pertussis & Inactivated Poliovirus Vaccine according to the schedule of Hong Kong Childhood Immunisation Programme. Of note, the patients’ parents also reported to have on and off cough during mid-September and mid-October respectively, and their per-nasal swabs collected on October 16 were all tested negative for Bordetella pertussis. The other home contact was asymptomatic and chemoprophylaxis was given to all home contacts.

CA-MRSA cases in September 2018 In September 2018, CHP recorded a total of 98 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 67 males and 31 females with ages ranging from 14 days to 85 years (median: 36.5 years).Among them, there were 76 Chinese, 6 Caucasian, 6 Filipinos, 3 Nepalese, 3 Pakistani, 2 Indian, 1 Indonesian, and 1 Sri Lankan.

Ninety-seven cases presented with uncomplicated skin and soft tissue infections while the remaining case had severe CA-MRSA infection. The severe case affected a 59-year-old woman with underlying medical illnesses. She presented with blood-stained sputum since August 1. She attended the general outpatient clinic (GOPC) of a public hospital on September 8. Her sputum collected on September 10 was cultured positive for CA-MRSA. She was referred by the GOPC to the accident and emergency department of a public hospital on September 21 and was admitted for management. She was diagnosed with CA-MRSA pneumonia and was treated with antibiotics. She remained in a stable condition and was discharged on October 3.

Among the 98 cases, two sporadic cases involved healthcare workers (a nurse and a healthcare assistant) who worked in different hospitals and investigation did not reveal any epidemiological linkage. Besides, three household clusters, with each affecting two persons, were identified in September.

Scarlet fever update (September 1, 2018 – September 30, 2018) Scarlet fever activity increased in September. CHP recorded 96 cases of scarlet fever in September as compared with 69 cases in August. The cases recorded in September included 56 males and 40 females aged between one and 40 years (median: five years). There were two institutional clusters occurring in two kindergarten-cum-child care centres, affecting five children in total. No fatal cases were reported in September.

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EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C, Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Update on the global situation of monkeypox infection in humans Reported by Ms Sheree CHONG, Scientific Officer, Communicable Disease Surveillance and Intelligence Office, Surveillance and Epidemiology Branch, CHP.

Background1,2 Monkeypox is a rare zoonotic disease caused by monkeypox virus, which belongs to the genus of orthopoxvirus. The virus was first discovered and named in 1958 during a pox-like disease outbreak in captive monkeys for research in Denmark. Monkeypox virus can cause infection in humans with symptoms similar to those seen in smallpox patients, but in a much milder form.

The first human case of monkeypox was recorded in 1970 in the Democratic Republic of Congo (DRC). Since then, human infection has been reported in a number of central and western African countries with the majority of cases occurring in DRC. With the eradication of smallpox in 1980 and subsequent cessation of smallpox vaccination, monkeypox has become the dominant cause of orthopoxvirus outbreaks in humans, primarily in regions of the Congo Basin and western Africa. Outbreaks in these regions typically occur in remote forested areas where there is frequent human contact with infected animals.

Monkeypox situation in West and Central Africa3,4,5,6 In the past decade, apart from DRC, the number of monkeypox cases in other central and western African countries has been increasing (Figure 1). This might be attributed to closer contact between humans and animals through deforestation, demographic changes, climate change, hunting, and population movement. Moreover, waning population immunity induced by smallpox vaccination and lack of protection among younger age groups following the eradication of smallpox in 1980, and the cessation of smallpox vaccination in the early 1980s might have contributed to the resurgence of the disease.

Since 2016, human monkeypox cases have been reported and confirmed from DRC (>1 000 reported per year), Nigeria (115), Republic of the Congo (88), Central African Republic (33), Liberia (two), Cameroon (one case) and Sierra Leone (one). There was also an outbreak of monkeypox in captive chimpanzees reported in Cameroon Figure 1 - African countries reporting human and animal monkeypox cases in 2016. from 2010 through 2018. (Source of information: WHO)

Nigeria An ongoing outbreak of monkeypox has started in September 2017 in Nigeria, approximately 40 years after its last recorded cases in 1978. It was the largest documented outbreak of human monkeypox in western Africa. Epidemiological investigations revealed that the initial cases affected a family with all the infected family members having developed similar symptoms of fever and generalised skin rash over a period of four weeks after contact with a captured monkey. However, the monkey had no known history of illness and it could not be ascertained if it was the source of their infection.

COMMUNICABLE DISEASES WATCH 94 Oct 21 - Nov 3 2018 WEEKS 43 - 44 VOL 15 ISSUE NO 22 From the onset of the outbreak in September 2017 through September 15, 2018, a total of 269 suspected cases across 25 states and one territory, including 115 confirmed cases across 16 states and one territory, have been reported. Seven deaths were recorded, four of which were patients with a pre-existing immunocompromised condition. There were two health care workers among the confirmed cases. The most affected age group was 21 to 40 years and 79% of the confirmed cases were males. A few family clusters were identified during this outbreak, but most patients had no apparent epidemiologic linkage or person-to- person contact. Together with the results from genetic analysis, the information suggested that there were multiple introductions of the monkeypox virus into the population with evidence of human-to-human-transmission. The West African clade of monkeypox virus was detected in the confirmed cases, which was less virulent and transmissible to humans compared to the Central African clade.

Monkeypox situation outside of Africa The first time that human monkeypox cases were reported outside of Africa was in 2003 in the United States of America (USA)7. Upon investigations, it was found that a shipment of approximately 800 small mammals from Ghana to Texas introduced monkeypox virus into the USA. Amongst the shipment three rope squirrels, two giant pouched rats, and nine dormice were infected with monkeypox virus. The infected rodents were housed in close proximity with prairie dogs which became infected with monkeypox virus and were sold as pets prior to their developing signs of infection. Subsequently, a total of 47 persons from six states were affected, all with history of contact with infected pet prairie dogs.

Imported cases of monkeypox have also been reported recently outside African region including the United Kingdom and Israel as detailed below.

United Kingdom (UK)8,9,10 In September 2018, two imported cases of monkeypox were reported in the UK on September 8 and 11, respectively. Upon contact tracing of the second imported case, a third case was identified on September 26. This was the first time monkeypox was diagnosed in England and the second outbreak of monkeypox reported outside of Africa.

The first imported case was a Nigerian naval officer attending a course at a naval base in Cornwall at the southwest of England. On the second day upon arrival in the UK, the patient developed fever, and rash in the groin area which later spread to the torso, face and arms. The second imported case was a UK resident who spent several weeks in Nigeria on holiday. The patient reported having contact with an individual with a monkeypox-like rash at a large family event and consumption of bush meat during the visit to a rural area of Nigeria. Both imported cases were believed to have contracted the infection in Nigeria as they had visited areas in southern Nigeria where human cases of monkeypox have recently been reported. However, there was no evidence suggesting that these two cases were epidemiologically linked. Genetic sequence data for both imported cases were consistent with the Nigerian strains of the West African clade. The third case was a healthcare worker who provided care to the second imported patient. This case was identified during contact tracing by the UK health authorities.

Israel11 On October 12, 2018, Israel reported an imported human monkeypox case. The patient was an Israeli man who lived and worked in Port Harcourt in southern Nigeria. The man began to show symptoms about a week after he returned from Nigeria. He was put in home isolation and his condition was improving.

As the outbreak in Nigeria is still ongoing and sporadic cases have been reported in several central and western African countries, the World Health Organization assessed that it was not unexpected to detect sporadic cases among returning travellers from endemic areas/countries. Due to the self-limiting and sporadic transmission pattern of monkeypox virus, and the prompt public health measures taken by local health authorities together with international partners, there was low potential for further spread of the disease within or from the UK and Israel.

Preventive measures There is currently neither specific treatment nor locally licensed vaccine for monkeypox infection. To reduce the risk of infection during human monkeypox outbreaks, members of the public should: ✦ Avoid close physical contact with sick persons or animals, especially when travelling to endemic areas; ✦ Wear protective clothing and equipment including gloves and surgical masks when taking care of ill people or handling animals, and carry out regular hand washing with soap and water or alcohol-based sanitiser after these procedures; ✦ Thoroughly cook all animal products before eating, and refrain from eating or handling bush meat; and ✦ Seek medical advice promptly for any suspicious symptoms, and provide information about all recent travel and immunisation history to the attending medical practitioner.

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What is monkeypox?1,10 Monkeypox is a rare caused by monkeypox virus, which like the variola virus causing smallpox, also belongs to the genus of orthopoxvirus. Infection could occur when a person comes into contact with the virus from animals, humans or contaminated materials. Humans could get infected from various wild animals, such as some species of primates, rodents and squirrels, through bite or scratch, or direct contact with their body fluids. Human-to-human transmission is also possible through respiratory droplets during prolonged face-to-face contact or direct contact with body fluids.

The incubation period is usually from six to 16 days, with a range from five to 21 days. The symptoms are similar to those of smallpox, but in milder forms. The clinical presentation in the first few days after symptoms onset is characterised by fever, intense headache, myalgia and lymphadenopathy. Rash appears about one to three days after onset of fever, and spreads from the face to other parts of the body. The development of swollen lymph nodes before the appearance of the rash occurs in some patients, which is a distinctive feature of monkeypox compared to other similar diseases such as chickenpox. The illness is usually mild and most of those infected will recover within a few weeks without treatment. The case fatality in previous monkeypox outbreaks were between 1% and 10%.

Monkeypox can only be diagnosed definitively in the laboratory through virus isolation, antigen and nucleic acid detection.

There are two genetically distinct groups of monkeypox virus – the West African and the Central African (Congo Basin). These two groups differ in disease severity and transmissibility to humans. The Central African clade is found to be more virulent and transmits more readily by direct contact and large respiratory droplet transmission. On the other hand, the West African clade, which is responsible for the recent Nigerian outbreak, is associated with a milder disease, lower mortality and limited human-to-human transmission.

There is currently no treatment or vaccine available for monkeypox infection. Treatment for monkeypox is mainly supportive. It has previously been shown that vaccination against smallpox was 85% effective in preventing monkeypox. However, the vaccine is no longer available on the market after it was discontinued following global smallpox eradication.

References 1Monkeypox fact sheet (June 6, 2018). World Health Organization. Available at: https://www.who.int/en/news-room/fact-sheets/detail/monkeypox. 2Brown, K., & Leggat, P. A. (2016). Human Monkeypox: Current State of Knowledge and Implications for the Future. Tropical medicine and infectious disease, 1(1), 8. doi:10.3390/tropicalmed1010008. 3Emergence of monkeypox in West Africa and Central Africa, 1970-2017. Weekly Epidemiological Record (March 16, 2018). World Health Organization. Available at: http://www.who.int/wer/2018/wer9311/en/. 4About Monkeypox (October 24, 2018). US Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/poxvirus/monkeypox/about.html. 5Reemergence of Human Monkeypox in Nigeria, 2017. Emerging Infectious Diseases (June 6, 2018). Available at: https://wwwnc.cdc.gov/eid/article/24/6/pdfs/18-0017.pdf. 6Monkeypox - Nigeria (October 5, 2018). World Health Organization. Available at: https://www.who.int/csr/don/05-october-2018-monkeypox-nigeria/en/. 72003 U.S. Outbreak (September 28, 2018). US Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/poxvirus/monkeypox/outbreak.html. 8Imported cases of monkeypox diagnosed in England. Health Protection Report volume 12 issue 33: news (September 14, 2018). Public Health England. Available at: https://www.gov.uk/government/publications/health-protection-report-volume-12-2018/hpr-volume-12-issue-33-news-14-september. 9Monkeypox case in England (September 26, 2018). Public Health England. Available at: https://www.gov.uk/government/news/monkeypox-case-in-england. 10Two cases of monkeypox imported to the United Kingdom, September 2018. Eurosurveillance (September 20, 2018). Available at: https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2018.23.38.1800509. 11Monkeypox Patient Diagnosed (October 12, 2018). Ministry of Health, State of Israel. Available at: https://www.health.gov.il/English/News_and_Events/Spokespersons_Messages/Pages/12102018_1.aspx.

COMMUNICABLE DISEASES WATCH 96 Oct 21 - Nov 3 2018 WEEKS 43 - 44 VOL 15 ISSUE NO 22 Update on Norovirus-associated Acute Gastroenteritis Outbreaks in Hong Kong Reported by Dr KONG Wai-chi, Scientific Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Acute gastroenteritis (AGE) can be caused by many viral or bacterial pathogens, the most common of which is norovirus (NoV). NoV is highly contagious and can be transmitted by ingesting food or water contaminated with the virus; contact with contaminated objects, vomitus or faeces from infected persons; or aerosol spread with contaminated droplets of splashed vomitus1. AGE outbreaks associated with NoV have been reported in institutional settings including child care centres (CCC), kindergartens (KG), schools, residential care homes for the elderly (RCHE), hospitals and cruise ships1,2. A person usually develops symptoms 12 to 48 hours after exposure to NoV. Common symptoms include nausea, vomiting, diarrhoea, abdominal pain, fever and malaise. The symptoms are usually self-limiting and most people will recover within one to three days. However, severe NoV infections can lead to hospitalisation, increased morbidity and even deaths especially in infants, children, the elderly and immunocompromised people3.

In Hong Kong, the Centre for Health Protection (CHP) of the Department of Health requires institutions to report suspected outbreaks of AGE to CHP for investigation and control. From 2008 to 2018 (as of October 31, 2018), CHP recorded a total of 1 673 institutional AGE outbreaks affecting a total of 17 123 persons. Among these 1 673 outbreaks, the causative pathogens were confirmed in 852 (50.9%) outbreaks, with the majority being caused by NoV (698 outbreaks, 81.9%), followed by rotavirus (96 outbreaks, 11.3%), Clostridium difficile (26 outbreaks, 3.1%) and other pathogens (32 outbreaks, 3.8%) including Salmonella, sapovirus, astrovirus, etc.

From 2008 to 2017, there were a total of 666 NoV-associated Figure 1 - Annual number of NoV-associated AGE outbreaks and number of persons affected, 2008 to 2018 (as of October 31, 2018). AGE outbreaks recorded with the annual number ranging from 17 to 136. A total of 8 339 persons were affected with the annual number ranging from 216 to 1 675 (Figure 1). In the first ten months of 2018, a total of 32 NoV-associated AGE outbreaks have been recorded, affecting 383 persons.

In Hong Kong, NoV-associated AGE outbreaks occurred throughout the year but were usually more common in winter. Of the 666 outbreaks recorded from 2008 to 2017, over half (336, 50.5%) occurred from December to February (Figure 2).

Among the 698 NoV-associated AGE outbreaks recorded between 2008 and 2018 (as of October 31, 2018), the majority (355, 50.9%) occurred in RCHE, followed by CCC/KG (161, 23.1%), hospitals (51, 7.3%), residential care homes for persons Figure 2 - Cumulative number of NoV-associated AGE outbreaks by month, 2008 to 2017. with disabilities (RCHD) (38, 5.4%) and primary schools (37, 5.3%) (Figure 3). The remaining 56 (8.0%) outbreaks occurred in other institutions including correctional institutions, secondary schools, special schools, etc.

The number of persons affected in the NoV-associated AGE outbreaks ranged from two to 181 with a median of ten persons per outbreak. About half (332, 47.6%) outbreaks affected two to nine persons, while 277 (39.7%) outbreaks affected ten to 19 persons. Only 89 (12.7%) outbreaks affected 20 or more persons.

Of the 8 722 persons affected in the NoV-associated AGE outbreaks, 1 761 (20.2%) required hospitalisation. The majority Figure 3 - Annual number of NoV-associated AGE outbreaks by place of (1,116, 63.4%) of the hospitalised patients were affected occurrence, 2008 to 2018 (as of October 31, 2018).

COMMUNICABLE DISEASES WATCH 97 Oct 21 - Nov 3 2018 WEEKS 43 - 44 VOL 15 ISSUE NO 22 residents of RCHE with NoV-associated AGE outbreaks. Two fatal cases were recorded in 2008, affecting two women aged 95 and 97 years respectively from two different RCHE with NoV-associated AGE outbreak. Both patients had underlying medical illnesses.

CHP will continue to closely monitor the situation. To prevent NoV-associated AGE, members of the public should adopt general measures including maintaining good personal, food and environmental hygiene. Further information can be found in the CHP webpage via the link: https://www.chp.gov.hk/en/healthtopics/content/24/33.html.

Prevention of AGE Maintain good personal hygiene ✤ Wash hands thoroughly with liquid soap and water before handling food or eating, and after using the toilet or handling vomitus or faecal matter; ✤ Refrain from work or school, and seek medical advice if suffering from fever, vomiting or ; and ✤ Exclude infected persons and asymptomatic carriers from handling food and providing care to children, elderly and immunocompromised people.

Maintain good food hygiene ✤ Adopt the Five Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases; ✤ Drink only boiled water from the mains or bottled drinks from reliable sources; ✤ Avoid drinks with ice of unknown origin; ✤ Purchase fresh food from hygienic and reliable sources. Do not patronise illegal hawkers; ✤ Wash and peel fruit by yourself and avoid eating raw vegetables; and ✤ Cook all food, particularly shellfish, thoroughly before consumption.

Please visit the website of Centre for Food Safety (https://www.cfs.gov.hk/english/index.html) for more information on food safety.

Maintain good environmental hygiene ✤ Maintain good indoor ventilation; ✤ Cleanse vomitus/ faeces and disinfect the contaminated areas properly and immediately. Keep other people away from the contaminated areas during cleansing; ✤ Wear gloves and a surgical mask while disposing of or handling vomitus and faeces, and wash hands thoroughly afterwards; ✤ Maintain proper sanitary facilities and drainage system; and ✤ Cleanse and disinfect toilets used by infected person and the soiled areas.

References 1Centers for Disease Control and Prevention. About Norovirus. 2018. Available at: https://www.cdc.gov/norovirus/about/index.html, accessed on November 1, 2018. 2World Health Organization. International travel and health: Communicable diseases. 2018. Available at: http://www.who.int/ith/mode_of_travel/communicable_diseases/en/, accessed on November 1, 2018. 3Pang XL. Detection and laboratory diagnosis of noroviruses. The Norovirus: Elsevier; 2017.

COMMUNICABLE DISEASES WATCH 98 Oct 21 - Nov 3 2018 WEEKS 43 - 44 VOL 15 ISSUE NO 22 NEWS IN BRIEF

A local case of Streptococcus suis infection

On October 22, 2018, the Centre for Health Protection (CHP) recorded a case of Streptococcus suis infection affecting a 58-year-old woman with underlying illnesses. The patient recalled that her left index finger was bitten by a wild boar in Wong Tai Sin on October 10. She was then admitted to a public hospital on the same day and wound debridement was performed on October 11. The operative diagnoses were deep laceration of finger and tenosynovitis of hand and wrist. Her left index finger tissue collected on October 11 yielded Streptococcus suis and she was treated with antibiotics. She was stable and discharged on October 19. Her home contacts were asymptomatic.

A sporadic case of psittacosis

On October 26, 2018, CHP recorded a sporadic case of psittacosis affecting a 45-year-old woman with good past health. She had presented with fever, cough, difficulty in breathing and headache since October 12, and was admitted to a public hospital on October 18. Her chest X-ray showed rightmiddle zone hazziness and the clinical diagnosis was chest infection. She required intubation and was transferred to the Intensive Care Unit on October 19. Her condition improved upon treatment with antibiotics and she was transferred back to general ward on October 25. Her tracheal aspirate collected on October 19 was tested positive for Chlamydia psittaci DNA. Her condition was stable. She had no travel history and did not report any contact history of birds or their excreta during the incubation period. Her home contacts were asymptomatic.

Patient Engagement in Hand Hygiene Promotion: The Keys of Success on October 25 and 26, 2018

The workshop of “Patient Engagement in Hand Hygiene Promotion: The Keys of Success” was conducted on October 25 and 26, 2018. Two overseas speakers, Prof Yves Longtin from the McGill University of Canada and Mrs Rachel Thomson from the Royal Hobart Hospital of Australia, together with five local faculties delivered a range of enlightening sessions on hand hygiene, ranged from exploring the benefits of patient engagement on hand hygiene, experience sharing by the representatives of patient support group, to the update of hand hygiene promotion in healthcare setting. Specific topics on infection control include bacterial resistance to alcohol and chlorhexidine were also discussed. There were fruitful experience sharing and exchange of ideas by overseas and local experts through the panel discussion session. Participants were enlightened on the ways forward on hand hygiene promotion in our locality. All the information has been uploaded onto the Hong Kong Training Portal on Infection Control and Infectious Diseases (http://icidportal.ha.org.hk/Trainings/View/136).

Photo 1 - Representatives of patient support group (first and second from Photo 2 - Dr TY Wong (Head, ICB, CHP; first from left) was leading the right) in Prince of Wales Hospital were sharing their experience of engaging panel discussion session to discuss the ways forward of implementing patient to perform hand hygiene with speakers and audience. patient engagement programme on hand hygiene in healthcare setting.

COMMUNICABLE DISEASES WATCH 99 Nov 4 - Nov 17 2018 WEEKS 45 - 46 VOL 15 ISSUE NO 23

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Human infection of rat hepatitis E virus (HEV) Reported by Dr YH LEUNG, Senior Medical and Health Officer, Communicable Disease Division, Surveillance and Epidemiology Branch, CHP.

The usual HEV causing human infection belongs to Orthohepevirus A (HEV-A). Apart from HEV-A, the Orthohepevirus genus also has three other species, namely, Orthohepevirus B that circulates in chickens, Orthohepevirus C (HEV-C) in rats and ferrets, and Orthohepevirus D in bats1,2. HEV-C, also known as rat HEV, shares only 50% to 60% nucleotide identity with HEV-A.As there is substantial phylogenetic divergence between HEV-A and HEV-C, serologic and molecular tests for human HEV might miss HEV-C infection2.

Human infection by rat HEV has not been reported previously. The Microbiology Department of the University of Hong Kong (HKU) published their findings of the first report of human case of rat HEV infection in December 20182. In addition, HKU developed a new molecular test to detect this virus in humans.

The patient was a 56-year-old retired male who underwent deceased donor liver transplant in a public hospital on May 14, 2017 and was put on immunosuppressants for anti-rejection prophylaxis. Subsequently, the patient had persistent liver function derangement since mid-July 2017. He was asymptomatic at that time. His blood sample collected on August 22, 2017 tested positive for anti-HEV IgM antibody by the Public Health Laboratory Services Branch (PHLSB) of the Centre for Health Protection (CHP) of the Department of Health which was suggestive of HEV infection. However, the sample was negative for human HEV by molecular testing for HEV-A. Further laboratory investigation by HKU found that the HEV infection was caused by rat HEV.

To study if there were other cases in recent years, CHP provided 73 archived blood samples of patients with positive anti-HEV IgM antibody but negative for human HEV nucleic acid by molecular test to HKU for further testing. Retrospectively, HKU identified that a previously notified HEV case was caused by rat HEV and genetic sequencing results found that the viruses detected in the two cases were highly similar.

The second patient was a 70-year-old retired female with underlying illnesses on immunosuppression. She had developed abdominal pain, headache, anorexia, malaise and palpitation since May 1, 2017, and was admitted to a public hospital on May 4, 2017. She was discharged on May 8, 2017 and had recovered. Her blood sample collected on May 5, 2017 tested positive for anti-HEV IgM antibody by PHLSB.

CHP’s epidemiological investigation revealed that the two cases had no travel history during the incubation period of usual HEV infection. They both resided in Wong Tai Sin District and their residence was about two kilometres apart. No other findings suggestive of epidemiological link between the cases were identified. The two patients could not recall having direct contact with rodents or their excreta, or noticed rodents in their residence. However, the first case recalled having seen suspected rodent excreta in his home. Based on the available epidemiological information so far, the sources and routes of infection of these two immunocompromised patients could not be determined.

Hepatitis E infection is a notifiable infectious disease in Hong Kong and all clinically compatible infection with positive anti-HEV IgM antibody or detectable HEV RNA are classified as a case. In the past five years, the annual number of cases recorded ranged from 64 to 96 (Figure 1).There Figure 1 - Number of Hepatitis E cases, 2013 to 2018 (as of November 15, 2018). is no apparent upsurge of hepatitis E infection observed recently among

COMMUNICABLE DISEASES WATCH 100 Nov 4 - Nov 17 2018 WEEKS 45 - 46 VOL 15 ISSUE NO 23 the notified cases. As of November 15, 2018, a total of 39 cases were reported in 2018. Among all cases since 2013, 381 were local cases, 27 were imported cases and the others were unclassified cases. All were sporadic cases and no clusters were identified.

To enhance detection of human infection of rat HEV, PHLSB has implemented a molecular test targeting different hepatitis E viruses, and will further test those hepatitis E cases confirmed by serology with negative result for the nucleic acid of HEV-A.The Pest Control Advisory Section (PCAS) of the Food and Environmental Hygiene Department (FEHD) has on-going collaboration with HKU’s team by providing them tissue samples of rodents for research. As reported in HKU’s article mentioned above, the internal organs of a sewer rat (Rattus norvegicus) provided by PCAS of FEHD in 2012 tested positive for rat HEV.

The public health implications of the detection of two human infections of rat HEV requires further study. However, the apparent clustering of the two cases back in 2017 is of concern and CHP will continue to closely monitor the situation. The most important preventive measures for the transmission of HEV are food and environmental hygiene, including rodent control. As a new measure, CHP will inform PCAS of FEHD to carry out rodent survey and control measures for all hepatitis E cases that are found to be caused by rat HEV.

To prevent HEV infection, the public is advised to adopt the Five Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases. In daily living, they are, to:

✦ Maintain hygienic practices such as hand washing with safe water, particularly before handling food or eating, and after using the toilet or handling vomitus or faecal matter; ✦ Obtain drinking water from the mains and boil it before consumption; ✦ Avoid consumption of water and ice of unknown purity; ✦ Purchase fresh food from reliable sources. Do not patronise illegal hawkers; ✦ Clean and wash food thoroughly; ✦ Cook food, especially seafood (e.g. shellfish), pork and pig offal, thoroughly before consumption. Avoid raw food or undercooked food; and ✦ Use separate chopsticks for handling raw food and cooked food when having hotpot.

References 1Sridhar S,Teng JLL, Chiu TH, Lau SKP,Woo PCY. Hepatitis E Virus Genotypes and Evolution: Emergence of Camel Hepatitis E Variants. Int J Mol Sci. 2017;18(4). 2Sridhar S,Yip CCY,Wu S, Cai J, Zhang AJX, Leung KH, et al. Rat hepatitis E virus as cause of persistent hepatitis after liver transplant. Emerg Infect Dis. 2018 Dec.Available at: https://doi.org/10.3201/eid2412.180937.

Regional Symposium on Antimicrobial Resistance Reported by Dr Jonathan NGAI, Medical and Health Officer and Dr Ken NG, Consultant, Infection Control Branch, CHP

Antimicrobial resistance (AMR) poses a global threat to the sustainable development of human medicine, veterinary medicine and food security by reducing available options to treat and prevent bacterial infections, and the "One Health" approach has been identified as a major element of AMR control and preventive strategies.

On November 13 to 14, 2018, a two-day Regional Symposium on Antimicrobial Resistance was jointly organised by the Department of Health (DH), the Agriculture, Fisheries and Conservation Department, and the Food and Environmental Hygiene Department, calling on healthcare professionals, partners from other sectors and the general public to work together to combat AMR.

Under the theme "Fighting AMR – Partnerships in Action", the Symposium has brought together experts and partners from public health, human and veterinary medicine, agriculture, food, environment and the pharmaceutical industry to review the latest science and gain insights on how to do better in tackling AMR in unity. More than 300 delegates from the western Pacific Region including Hong Kong, Mainland China, Macao, Japan, Singapore and Korea joined the Symposium.

The Symposium aimed to provide a platform for participants to exchange their expertise and experiences and aim to raise awareness of AMR in the community in the Western Pacific region. At the Symposium, world-renowned speakers shared their expertise and experience in translating their AMR action plans into action. COMMUNICABLE DISEASES WATCH 101 Nov 4 - Nov 17 2018 WEEKS 45 - 46 VOL 15 ISSUE NO 23

“Stop treating with antibiotics like treats”, warned Lord O’Neill, the Honorary Professor of Economics at the University of Manchester and Author of the Review on AMR of the United Kingdom. Lord O’Neill also elaborated on AMR’s impact on economy and sustainability upon the plenary lecture. Dr Carmem Pessoa-Silva, the Lead of AMR Surveillance of the World Health Organization (WHO), shared the latest update and development on WHO Global Antimicrobial Resistance Surveillance System. Dr Juan Lubroth, the Chief Veterinary Officer of the Food and Agriculture Organization of the United Nations, discussed the complexity of AMR from animal and food production aspect.

During the symposium, global collaboration and a multi-sectoral "One Health" approach was emphasised. The value of surveillance, efforts in optimising antibiotic use in human and animals, and the impact of infection control and awareness-raising campaigns were discussed while the challenges encountered in new drug development were emphasised by numerous speakers.

The Symposium was one of the major events taking place in conjunction with World Antibiotic Awareness Week (WAAW) 2018 from November 12 to 18. In parallel with WAAW 2018, healthcare professionals are again requested to refer to the guidelines on the use and choice of antibiotics, while patients should strictly adhere to doctors' instructions and should not use antibiotics indiscriminately. For more information on these issues, please visit the WHO’s page on WAAW 2018 (http://www.who.int/who-campaigns/world-antibiotic-awareness-week) and page of the DH’s Centre for Health Protection (https://www.chp.gov.hk/en/features/100981.html).

Photo 1 - Secretary for Food and Health Photo 2 - Over 300 delegates from the western Photo 3 - Lord O’Neill delivered the plenary together with the organisers kicked off the Pacific Region attended the Regional Symposium. lecture on - Sustainability and economic impact symposium. of AMR.

NEWS IN BRIEF

A local sporadic case of listeriosis

On November 4, 2018, the Centre for Health Protection (CHP) recorded a sporadic case of listeriosis affecting a 72-year-old woman with end stage renal failure on continuous ambulatory peritoneal dialysis (CAPD). She had presented with fever, abdominal pain, vomiting, diarrhoea and turbid peritoneal dialysate since November 2 and was admitted to a public hospital on the same day. Her peritoneal dialysate collected on November 2 grew Listeria monocytogenes.The clinical diagnosis was CAPD peritonitis and she was treated with antibiotics. She was stable and discharged on November 16. She had no recent travel history. She did not recall consuming any high risk food during the incubation period. Her household contacts remained asymptomatic.

COMMUNICABLE DISEASES WATCH 102 Nov 4 - Nov 17 2018 WEEKS 45 - 46 VOL 15 ISSUE NO 23

A sporadic case of psittacosis

On November 6, 2018, CHP recorded a sporadic case of psittacosis affecting a 56-year-old female with underlying illnesses. She had presented with fever, sore throat, cough and runny nose since October 20. She attended the Accident and Emergency Department (AED) of a public hospital and was admitted for management on October 24. Her chest X-ray showed left middle zone haziness and the clinical diagnosis was pneumonia. Her sputum collected on October 24 was tested positive for Chlamydia psittaci DNA by polymerase chain reaction (PCR). She was treated with antibiotics. She remained stable and was discharged on October 27. She had no recent travel history. She did not recall direct contact with birds, bird droppings or bird carcasses during the incubation period. Her home contacts remained asymptomatic.

A sporadic case of Streptococcus suis infection

On November 9, 2018, CHP recorded a sporadic case of Streptococcus suis infection affecting a 71-year-old man with good past health. He had presented with fever, dizziness and nausea since November 8. He attended the AED of a public hospital and was admitted on November 8. The clinical diagnosis was sepsis. His blood culture was tested positive for Streptococcus suis. He was treated with course of antibiotics and his condition remained stable. He had history of handling raw pork at home during incubation period but did not have wounds on hands. He had no travel history during the incubation period. His home contacts remained asymptomatic.

CA-MRSA cases in October 2018

In October 2018, CHP recorded a total of 115 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 69 males and 46 females with ages ranging from two months to 94 years (median: 35 years). Among them, there were 93 Chinese, 5 Caucasian, 5 Nepalese, 4 Filipinos, 2 Pakistani, 1 Indian, 1 Indonesian, and 4 of unknown ethnicity.

One hundred and fourteen cases presented with uncomplicated skin and soft tissue infections while the remaining case had severe CA-MRSA infection. The severe case affected a 22-year-old man who presented with fever and right buttock pain since October 10. He attended the AED of a public hospital on October 15 and was admitted on the same day.The clinical diagnosis was right buttock abscess with bacteremia. He was treated with incision and drainage of right buttock abscess and antibiotics. Blood specimen and pus collected from his right buttock abscess on October 15 were both cultured positive for CA-MRSA. He remained in a stable condition.

Separately, the isolates of two cases were found to be resistant to mupirocin. The first case involved a five-year-old boy who presented with on his right leg in mid-September and recovered after antibiotic treatment. The second case involved a 91-year-old woman who had right scalp abscess in early October. She was treated with antibiotics and surgical drainage. Her condition remained stable.

Besides, six household clusters, with each affecting two persons, were identified. No cases involving healthcare worker were reported in October.

Scarlet fever update (October 1, 2018 – October 31, 2018)

Scarlet fever activity has increased in October. CHP recorded 162 cases of scarlet fever in October as compared with 97 cases in September.The cases recorded in October included 95 males and 67 females aged between nine months and 52 years (median: six years). Among them, there was a case requiring admission to paediatric intensive care unit (PICU). This case affected a 13-year-old boy with underlying illnesses. He presented with fever, sore throat and sandpaper-like rash over body since October 20. He was admitted to a public hospital and subsequently transferred to PICU for further management because of shock on October 21. The clinical diagnosis was scarlet fever with toxic shock syndrome. He was treated with antibiotics. His condition was stabilised and he was discharged on October 28.There were six institutional clusters occurring in three kindergartens/child care centres, two primary schools and a special school, affecting 14 children in total. No fatal cases were reported in October.

COMMUNICABLE DISEASES WATCH 103 Nov 18 - Dec 1 2018 WEEKS 47 - 48 VOL 15 ISSUE NO 24

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS New series of Guidance Notes on Antibiotic Stewardship in Primary Care Reported by Dr Leo LUI, Associate Consultant, Infection Control Branch, CHP.

Antimicrobial resistance (AMR) is a global public health problem. For the past few decades, AMR has been a growing threat to effective treatment for an ever-increasing number of infections caused by bacteria, viruses, fungi and parasites. AMR results in reduced efficacy of antimicrobials, making the treatment of patients difficult, costly or even impossible, causing prolonged course of illness and increased disease mortality.

In July 2017, the Government of the Hong Kong Special Administrative Region (HKSAR) launched the Hong Kong Strategy and Action Plan on Antimicrobial Resistance (2017-2022). It adopted the “One Health” approach as recommended by international health agencies such as the World Health Organization, as a holistic model with a view to curb the growing threat of AMR in Hong Kong. Among the different aspects of the One Health approach, one of the key areas is to optimise the use of antimicrobials in the healthcare settings.

Antibiotic Stewardship Programme (ASP) is identified as a key measure for improving patient outcomes by reducing unnecessary prescriptions, and when they are genuinely needed, ensuring these important drugs are used at a proper dose and the duration is kept to be as short as necessary without compromising patient safety. A successful ASP has many potential benefits, including delaying the emergence of resistant micro-organisms, minimising adverse effects of antimicrobials and their administration, reducing length of hospital stay and thus the incidence of healthcare-associated infections, and finally often a reduction of the cost of antimicrobials. Broadly speaking, ASP can be implemented in almost all healthcare settings, including both in- and out-patient facilities.There are different ways of delivering an ASP model, one important means is through provision of professional guidance in an easily-accessible and user-friendly manner.

The Centre for Health Protection (CHP) of the Department of Health launched the Antibiotic Stewardship Programme in Primary Care (ASP in PC) in November 2017. Evidence-based Guidance Notes (GNs) for common infections diagnosed by primary care doctors (such as acute pharyngitis, acute uncomplicated cystitis in women and simple (uncomplicated) skin and soft tissue infections) were developed. Health education materials including patient information sheets, posters, pamphlets and tips for taking antibiotic cue cards were also made available to assist primary care doctors to explain to patients the nature of diseases and the importance of compliance with doctors' instructions when patients were prescribed with an antibiotic. The GNs were then promulgated through Continuing Medical Education ("CME") seminars to primary care doctors.

The Infection Control Branch (ICB) of CHP organised nine briefing sessions of ASP in PC from December 2017 to March 2018 for medical doctors in Hong Kong. A questionnaire survey was conducted to over 400 participants. Results showed that GNs were considered useful and had strong influence on doctors’ decision in antibiotic prescription.

COMMUNICABLE DISEASES WATCH 104 Nov 18 - Dec 1 2018 WEEKS 47 - 48 VOL 15 ISSUE NO 24 With positive feedback from primary care doctors, the Advisory Group on ASP in PC continued to develop the second series of GNs (Figure 1) on common infections seen by primary care doctors.There are four conditions focusing on the upper respiratory tract and lower respiratory tract conditions in the new set of guidance notes. The topics are: 1) acute otitis media, 2) acute rhinosinusitis, 3) community- acquired pneumonia, and 4) acute exacerbations of chronic obstructive pulmonary disease. In each guidance note, the indications of when to prescribe antibiotics, choices of appropriate agents, dose and duration of antibiotics are recommended based on the best available clinical evidence with a perspective of local practices. Each guidance note is presented in a long and short version, with the long version serving to explain the rationale of recommendations in details Figure 1 - The second series of Guidance Notes. while the short versions (in the form of A5-sized quick reference guides) are intended to be used conveniently by primary care doctors at the point of care during or in between patient consultations.

As in the previous round, patient information sheets are also prepared to facilitate doctors to teach patients how to properly use antibiotics and to understand more about their course of illness in general. Electronic copies of the guidance notes are being uploaded onto the webpage of ASP in PC (https://www.chp.gov.hk/en/features/ 49811.html) (Figure 2).

Hard copies will be distributed to individual primary care doctors, medical groups, private hospitals and other doctors as necessary. Recommended practices will also be promulgated through CME seminars to primary care doctors in Q4 of 2018 and Q1 of 2019. For the first time ever, these seminars will be broadcasted live through CME-approved online video streaming platforms viewable by primary care doctors who are unable to attend the seminar in person but are enrolled with the CME programme. Figure 2 - The webpage of Antibiotic Stewardship Programme in Primary Care.

HPV Vaccination for Cervical Cancer Prevention Reported by Dr HO King-man, Head of Public Health Services Branch, CHP.

Human Papillomavirus (HPV) is a small non-enveloped double stranded DNA virus. There are more than 200 types of papillomavirus, of which around 40 infect human mucosal areas including the anogenital tract. The 40 HPVs are divided into high risk and low risk HPV (HR-HPV and LR-HPV respectively) according to their oncogenic potential. Persistent infection of the HR-HPVs may cause cancer of the infected mucosae. In local studies, HPV-16 and HPV-18 are the most commonly identified HR-HPVs in cervical cancer specimens and together they accounted for about 70% of cervical cancer, HR-HPV type 52, 58, 33, 31 and 45 in descending order of occurrence are the other HPV identified in another 20% of cervical cancer specimens1,2,3. Whereas HPV-6 and HPV-11 are the commonest low-risk HPVs (LR-HPV) that cause anogenital warts.

Transmission of genital HPV infection is mainly through sexual contact (both vaginal and anal sex) with an infected person. Primary prevention of cervical cancer involves behavioural modification including safer sex with condom usage, reducing number of sexual partners, avoidance of smoking and vaccination against HR-HPVs. Secondary prevention involves cervical screening to identify and treat precursor lesions of invasive cervical cancer.A territory wide cervical screening programme has been launched in Hong Kong since 2004 to reduce the local cervical cancer burden.

COMMUNICABLE DISEASES WATCH 105 Nov 18 - Dec 1 2018 WEEKS 47 - 48 VOL 15 ISSUE NO 24 Local Burden of Cervical Cancer In 2016, cervical cancer was the ninth leading cause of female cancer deaths in Hong Kong and there were 151 registered deaths, accounting for 2.6% of total female cancer deaths. The age-standardised incidence rate decreased from 9.5 per 100 000 standard female population in 2004 when the Cervical Screening Programme was established to 8.4 per 100 000 standard female population in 2015. Likewise, the age-standardised mortality rate decreased from 2.6 per 100 000 standard female population to 2.2 per 100 000 standard female population from 2004 to 2016 (Figure 1).

HPV Vaccines Three HPV vaccines are available to date.The quadrivalent vaccine targets HPV types 6, 11, 16 and 18. The bivalent vaccine targets HPV types 16 and 18. The nonavalent vaccine targets HPV types * 6, 11, 16, 18, 31, 33, 45, 52, and 58. The attributes and dosing Figure 1 - Age-standardised incidence and mortality rates of cervical cancer in Hong Kong, 1981 to 2016. recommendations are summarised in Table 1. Apparently, the Notes: nonavalent HPV vaccine covers the seven HR-HPV accounting for 1. *Age-standardised rates are compiled based on the world standard about 90% of the local cases of cervical cancers in Hong Kong. population specified in GPE Discussion Paper Series: No.31, EIP/GPE/ EBD,World Health Organization, 2001. 2. Data in the above charts from 1996 onwards are compiled based Efficacy and duration of protection on the population estimates under the "resident population" Studies in HPV naïve women showed that both the quadrivalent approach instead of the "extended de facto" approach. Also, the and bivalent vaccine achieved a high level of protection (>90%) 2016 Population By-census conducted from June to August 2016 provides a benchmark for revising the population figures compiled against HPV-16/18 related cervical cancer precursor lesions, which since the 2011 Population Census. Population-related figures from acted as surrogate endpoints for cervical cancer4,5. The actual 2012 to 2015 have been revised accordingly. duration of protection of vaccine will need to be established by 3. Classification of diseases and causes of death is based on the long term efficacy studies. The maximum duration of clinical International Statistical Classification of Diseases and Related Health Problems (ICD) 10th Revision from 2001 onwards. Figures from 2001 studies published to date is more than 10 years for the bi and onwards may not be comparable with figures for previous years which quadrivalent vaccine. were compiled based on the ICD 9th Revision. (Sources: Census and Statistics Department, Department of Health Safety and Adverse Effects and Hong Kong Cancer Registry, Hospital Authority.) The common side effects of these vaccines include mild local Table 1 - The attributes and dosing recommendations of the three reaction, such as erythema, pain and swelling, and systematic registered HPV vaccines available in Hong Kong. adverse effects such as muscle aches, fever, headache and nausea. 4-valent The vaccine is contraindicated in persons with a history of 2-valent (HK-54934)(Vial) 9-valent Vaccines immediate hypersensitivity to yeast or any of the vaccine (HK-56180) (HK-54935) (HK-64239) components. Because of limited data, vaccination during (Prefilled Syringe) pregnancy is not recommended. There were concerns reported Against HPV-6, 11, 16, 18, 31, HPV-16, 18 HPV-6, 11, 16, 18 overseas about serious adverse events including, for example, HPV types 33, 45, 52, 58 anaphylaxis, syncope and Guillain-Barré syndrome (GBS). The Approved 9-14 years old: 9-13 years old: 9-14 years old: two regulatory authorities in North America and Europe, as well as dose two doses two doses doses the World Health Organization, have issued updated position regimen in 15 years old and 14 years old and 15 years old and Hong Kong statements reassuring the safety of HPV vaccine at various above: three doses above: three doses above: three doses occasions6,7,8.

The new school based HPV vaccination programme in Hong Kong The Scientific Committee on Vaccine Preventable Diseases and Scientific Committee on AIDS and Sexually Transmitted Infections of the Centre for Health Protection (CHP) of the Department of Health (DH) after reviewing the scientific evidence and overseas vaccination programmes, local acceptability and cost benefit analysis recommended HPV vaccination to be included in Hong Kong Childhood Immunisation Programme (HKCIP) as a public health programme for cervical cancer prevention for girls of suitable ages before sexual debut.The Government is committing for a local HPV vaccination programme and CHP is planning to include HPV vaccination in HKCIP for school girls starting in the 2019-2020 school year. The first cohort for the HPV vaccination will be girls studying in Primary 5 in the 2019-2020 school year. The second dose will be given when they reach Primary 6. Similar to other vaccines administered to primary school children under HKCIP, eligible school girls will be given HPV vaccination throughout a school year via outreach by the School Immunisation Teams of DH during scheduled visits.

COMMUNICABLE DISEASES WATCH 106 Nov 18 - Dec 1 2018 WEEKS 47 - 48 VOL 15 ISSUE NO 24 Summary Evidence showed that HPV vaccine and population based programme is effective in preventing cervical cancers. The new nonavalent HPV vaccine covers HR-HPV types that account for about 90% of all cervical cancers. It is most effective when administered to girls before sexual debut. CHP is planning to include HPV vaccination in HKCIP for school girls starting in the 2019-2020 school year. The forthcoming HPV vaccination programme will be a school based programme with the first dose of HPV vaccine delivered to Primary 5 school girls.As protection is mainly for serotypes included in the vaccine, cervical screening remains an important part of cervical cancer prevention even with HPV vaccination.

References 1Chan PK, Cheung TH, Tam AO, et al. Biases in human papillomavirus genotype prevalence assessment associated with commonly used consensus primers. Int J Cancer. 2006 Jan 1;118(1):243-5. 2Chan PK, Ho WC, Yu MY, et al. Distribution of human papillomavirus types in cervical cancers in Hong Kong: Current situation and changes over the last decades. Int J Cancer. 2009 Oct; 125(7):1671-7. 3Lau YM, Cheung TH, Yeo W, et al. Prognostic implication of human papillomavirus types and species in cervical cancer patients undergoing primary treatment. PLoS One. 2015 Apr 9;10(4):e0122557. 4Arbyn M, Xu L, Simoens C, Martin-Hirsch PPL. Prophylactic vaccination against human papillomaviruses to prevent cervical cancer and its precursors. Cochrane Database of Systematic Reviews 2018, Issue 5.Art. No.: CD009069. 5Joura EA, Giuliano AR, Iversen OE, et al. A 9-valent HPV vaccine against infection and intraepithelial neoplasia in women. N Engl J Med. 2015 Feb 19;372(8):711-23. 6US CDC. Human Papillomavirus (HPV) Vaccine Safety. Available at: https://www.cdc.gov/vaccinesafety/vaccines/hpv-vaccine.html, accessed on July 6, 2018. 7European Medicines Agency. HPV vaccines - Article-20 procedure - EMA confirms evidence does not support that they cause CRPS or POTS, 20/01/2016. Available at: https://www.ema.europa.eu/en/medicines/human/referrals/human-papillomavirus-vaccines-cervarix-gardasil-gardasil-9- silgard#overview-section, accessed on July 6, 2018. 8WHO. Meeting of the Global Advisory Committee on Vaccine Safety, June 7 to 8, 2017. Weekly Epidemiological Record, 14 July 2017, vol. 92, 28 (pp. 393-402). Available at: http://apps.who.int/iris/bitstream/handle/10665/255870/WER9228.pdf?sequence=1, accessed on July 6, 2018. 9Scientific Committee on AIDS and STI and Scientific Committee on Vaccine Preventable Diseases. Joint Consensus Recommendation on the Use of 9-valent Human Papillomavirus Vaccine in Prevention of Cervical Cancer in Hong Kong. Available at: https://www.chp.gov.hk/files/pdf/ joint_consensus_recommendation_on_the_use_of_9_valent_human_papillomavirus_vaccine_in_prevention_of_cervical_cancer_in_hong_.pdf, accessed on October 12, 2018. 10The Government of the Hong Kong Special Administrative Region. Press release - HPV vaccine to be provided under Childhood Immunisation Programme.Available at: https://www.info.gov.hk/gia/general/201810/11/P2018101100552.htm, accessed on October 12, 2018.

NEWS IN BRIEF

A sporadic case of Listeriosis infection

On November 20, 2018, the Centre for Health Protection (CHP) recorded a case of listeriosis affecting an 80-year-old woman with underlying illnesses. She presented with fever, headache and malaise on November 7 and was admitted to a public hospital on November 11. The clinical diagnosis was sepsis. Her blood culture collected on November 11 yielded Listeria monocytogenes. She was treated with antibiotics and her condition was stable. She had travelled to Macau from October 18 to 20. She had consumed and salad during the incubation period. Her home contacts were asymptomatic. Investigation is on-going.

A sporadic case of psittacosis

On November 28, 2018, CHP recorded a case of psittacosis affecting a 70-year-old woman with underlying illnesses. She presented with fever, productive cough and shortness of breath on November 8. She was admitted to a public hospital on November 16 and was transferred to the intensive care unit for management on November 18. The clinical diagnosis was pneumonia. Her tracheal aspirate was tested positive for Chlamydophila psittaci DNA. She required intubation and mechanical ventilation. Her condition subsequently stablised with treatment. She had travelled to Zhangjiajie from November 2 to 5. She did not recall any contact history with birds or their excreta during the incubation period. Her home contact and travel collaterals were asymptomatic.

COMMUNICABLE DISEASES WATCH 107 Dec 2 - Dec 15 2018 WEEKS 49 - 50 VOL 15 ISSUE NO 25

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members Dr Yonnie Lam / Dr Albert Au / Dr TY Wong / Dr Gladys Yeung / Dr Philip Wong / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Second dose of measles-containing vaccine for children in Hong Kong to be advanced Reported by Ms Fanny WS HO, Scientific Officer, Vaccine Preventable Disease Office, Surveillance and Epidemiology Branch, CHP.

Measles immunisation was first introduced in Hong Kong in 1967 as a single dose of anti-measles vaccine (AMV) given at six months or above.The combined measles, mumps and rubella (MMR) vaccine replaced AMV in 1990 for children at 12 months to offer additional protection against mumps and rubella, and has been further administered as a two-dose regimen since 1996. At present, under the Hong Kong Childhood Immunisation Programme (HKCIP), children in Hong Kong are given the first dose of MMR vaccine at one year at Maternal and Child Health Centres (MCHCs) of the Department of Health (DH), followed by a second dose at Primary One by the School Immunisation Teams (SIT) of DH through outreach visits to schools.

Over the past two decades, measles has been successfully controlled in Hong Kong through sustaining very high coverage (>97%) of two-dose MMR vaccination and well-performing surveillance. In September 2016, the World Health Organization (WHO) confirmed that Hong Kong has achieved the interruption of endemic measles virus transmissiona (i.e. measles elimination). The reported number of measles in Hong Kong has remained at a very low level after elimination. There were nine, four and 12 cases confirmed in 2016, 2017 and 2018 (as of November 30, 2018) respectively with annualised incidence of 0.5 to 1.8 cases per million population which was well below the WHO target of less than five cases per million population.

However, measles remains an endemic infection in many places around the world and some countries experienced a reemergence of measles outbreaks in recent years. According to the data from WHO, the percentage of reporting countries with annual measles incidence of <5 cases per million population decreased from 69% in 2016 to 65% in 2017. During 2016-2017, reported measles cases increased 31% globally, 100% in the African Region, 6 358% in the Region of the Americas, 481% in the Eastern Mediterranean Region, 458% in the European Region, and 3% in the South-East Asia Region1. In Southeast Asia, the 12-month measles incidence (number of cases per million population) from mid-2017 to mid-2018 was over 70 in Malaysia and the Philippines, and over 20 in Thailand and Indonesia2. In Europe, there were marked increases in measles cases in 2017-2018 in some countries, with the 12-month incidence over 100 in Greece and Romania3. The measles incidence rates in these countries were far higher than that of Hong Kong, which was 1.4 cases per million population during the period from July 2017 to June 2018. For persons who are not fully immunised, the risk of acquiring measles as a result of overseas travel exists.

Among the 129 measles cases reported in Hong Kong during 2013-June 2018, 58 were either imported (55 cases, 42.6%) or import-relatedb (3 cases, 2.3%), including thirteen children aged five years or below. Some popular travel destinations among local people (e.g. Europe and some Asian countries such as the Philippines and Malaysia) are having high incidence or outbreaks of measles.Young children who have not completed the two doses of measles vaccination are at risk of contracting measles when travelling to these areas.

aEndemic measles virus transmission is defined by WHO as existence of continuous transmission of indigenous or imported measles virus that persists for at least 12 months. bCases with a known epidemiological linkage to another confirmed imported case.

COMMUNICABLE DISEASES WATCH 108 Dec 2 - Dec 15 2018 WEEKS 49 - 50 VOL 15 ISSUE NO 25 The Scientific Committee on Vaccine Preventable Diseases (SCVPD) under the Centre for Health Protection of DH had examined the MMR vaccination schedule for children in Hong Kong. After reviewing the current measles vaccination strategy, global and local epidemiology of measles, scientific evidence on effectiveness of measles-containing vaccines, WHO recommendations and overseas practices, SCVPD has recommended children to receive the first dose of MMR vaccine at 12 months as before, followed by a second dose as combined measles, mumps, rubella and varicella (MMRV) vaccine at 18 months instead of Primary One.After the change, mop-up MMRV vaccination is recommended for children with incomplete vaccination identified by DH’s SIT during routine school visits at Primary One.

This proposed change is expected to enhance protection against measles, mumps, rubella and chickenpox for young children before their entry into pre-school institutions (such as kindergartens and child care centres).This will also offer protection to those who did not respond to the first dose (primary vaccine failure) and potentially reduce the accumulation of susceptible young children. In the context of travel-related risk of measles infection, completing the two-dose regimen at 18 months may also prevent infection among young children during travel, in view of measles outbreaks reported from time to time in various regions of the world in recent years.

In addition, given the vaccine effectiveness of two doses of varicella vaccine (about 95%) is higher than one dose (about 83%)c, the change is expected to bring a secondary advantage of conferring better protection against varicella for young children and hence decreasing the risk of chickenpox outbreaks in pre-primary institutions, as children will be covered by two doses of varicella-containing vaccines by 18 months instead of Primary One.

Meanwhile, DH is working on the implementation details of the revised HKCIP schedule and the launch of the revised schedule in MCHCs will be announced in due course. For details of SCVPD’s recommendation, please visit the CHP website: https://www.chp.gov.hk/files/pdf/recommendation_on_the_schedule_of_the_second_dose_of_measles_containing_vaccine_in_hong_kong.pdf.

cAccording to the WHO position paper on varicella and herpes zoster vaccines (June 2014), a systematic review showed that single-dose vaccine had an approximate median effectiveness of 83% (range 20% to 100%) against all grades of disease severity in children aged from nine months to 12 years while two doses provided better protection (median: 95%) (http://www.who.int/immunization/policy/ position_papers/varicella/en/).

References 1Alya Dabbagh, Rebecca L. Laws, Claudia Steulet, et al. Progress Toward Regional Measles Elimination - Worldwide, 2000-2017. MMWR Morb Mortal Wkly Rep. 2018 Nov 30;67(47):1323-9. 2World Health Organization. Measles and Rubella Surveillance Data. Reported measles and rubella cases and incidence rates by Member States. Available at: http://www.who.int/immunization/monitoring_surveillance/burden/vpd/surveillance_type/active/measles_monthlydata/en/, accessed on November 29, 2018. 3European Centre for Disease Prevention and Control. Monthly measles and rubella monitoring report. June 2018. Available at: https://ecdc.europa.eu/sites/portal/files/documents/Monthly-Measles-Rubella-monitoring-report-June-2018.pdf, accessed on November 29, 2018.

NEWS IN BRIEF

A sporadic case of Listeriosis On December 6, 2018, the Centre for Health Protection (CHP) recorded a case of listeriosis affecting a 59-year-old woman with underlying illnesses. She had presented with on and off diarrhoea since November 26. She developed fever on November 30 and was admitted to a public hospital on December 3. She was subsequently transferred to the intensive care unit for further management of sepsis. Her blood culture collected on December 3 yielded Listeria monocytogenes. She was treated with antibiotics and her current condition was stable. She had no recent travel history and did not consume any high-risk food during the incubation period. Her home contact was asymptomatic.

A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection On December 13, 2018, CHP recorded a sporadic case of necrotising fasciitis due to Vibrio vulnificus infection affecting a 68-year-old male with underlying illnesses. He had presented with fever, left hand swelling and pain since December 10. He attended the Accident and Emergency Department (AED) of a public hospital on December 11 and was admitted on the same day.The clinical diagnosis was necrotising fasciitis. He was treated with antibiotics and left below elbow amputation. His blood specimen and left hand necrotic fascia tissues collected on December 11 were tested positive for Vibrio vulnificus. As of December 17, he remained hospitalised and his condition was serious. According to his wife, he had accidentally injured the dorsum of his left hand during the preparation of a barramundi (盲曹) at home on December 10. He had no recent travel history and his home contacts were asymptomatic.

COMMUNICABLE DISEASES WATCH 109 Dec 2 - Dec 15 2018 WEEKS 49 - 50 VOL 15 ISSUE NO 25

A sporadic case of psittacosis On December 14, 2018, CHP recorded a case of psittacosis affecting a 77-year-old retired man with underlying illness. He presented with fever, headache, myalgia, productive cough and shortness of breath on December 1, and was admitted to a public hospital on December 5. His chest X-ray showed left-sided consolidation and the clinical diagnosis was pneumonia complicated with acute kidney injury. He was treated with antibiotics and his condition was stable. Nasopharyngeal aspirate collected from the patient on December 8 was tested positive for Chlamydia psittaci DNA. He had three recent short trips to Panyu of one to two days each and did not report any contact history with birds or their excreta during the incubation period. His home contacts and travel collateral were asymptomatic.

A domestic cluster of pertussis CHP recorded a domestic cluster of pertussis affecting a three-month-old girl and her 34-year-old father in early December. The girl had presented with cough, post-tussive vomiting and reduced appetite since November 24 and was admitted to a public hospital on December 3. Her pernasal swab was tested positive for Bordetella pertussis on December 4. She was treated with antibiotic. She remained stable and was discharged on December 8. Contact tracing identified that she lived with parents who were asymptomatic and invited for screening. Both of them were tested negative for Bordetella pertussis and first dose of chemoprophylaxis had been started on December 5. However, her father developed cough and dizziness starting December 6. He attended the AED of a public hospital on December 7 and was found to have cardiogenic shock and was admitted to intensive care unit on the same day. His pernasal swab taken on December 7 was tested positive for Bordetella pertussis and CXR showed right middle zone consolidation.The clinical diagnosis was pneumonia due to pertussis and myocarditis. He was treated with antibiotics. He has recovered and was discharged on December 15.

Both cases had travelled to Shenzhen during the incubation period. The baby girl had received the first dose of diphtheria, tetanus, acellular pertussis and inactivated poliovirus (DTaP-IPV) vaccine while the father’s vaccination status against pertussis was unknown.

CA-MRSA cases in November 2018 In November 2018, CHP recorded a total of 97 cases of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA) infection, affecting 57 males and 40 females with ages ranging from two months to 86 years (median: 36 years). Among them, there were 73 Chinese, 5 Filipinos, 4 Nepalese, 2 Caucasian, 2 Indian, 2 Pakistani, 1 Indian, 1 Indonesian, 1 Malaysian, and 6 of unknown ethnicity.

Ninety-five cases presented with uncomplicated skin and soft tissue infections while the remaining two cases had severe CA-MRSA infections. The first severe case affected an 86-year-old man with good past health. He presented with fever and chills since October 23. He attended the AED of a private hospital on October 25 and was admitted on the same day. Blood specimen collected on October 27 was cultured positive for CA-MRSA.The clinical diagnoses were pneumonia and CA-MRSA septicemia. He was subsequently transferred to a public hospital for further management. He was treated with antibiotics and remained in a stable condition. The second severe case affected a 46-year-old woman with underlying illnesses. She had a pressure sore over her back since early November. She attended a private hospital for shortness of breath and decreased general condition on November 7 and was admitted to the intensive care unit on the same day. Her chest X-ray showed bilateral pneumonic changes. Her blood specimen collected on November 7 was cultured positive for CA-MRSA. The clinical diagnoses were pneumonia, back abscess and CA-MRSA septicemia. She was treated with antibiotics and incision and drainage of her back abscess. She remained in a stable condition.

Separately, the isolate of one case affecting a 16-year-old boy was found to be resistant to mupirocin. The patient presented with back abscess in mid-October. He was treated with antibiotics and his condition remained stable.

Besides, four household clusters, with each affecting two to three persons, were identified. No cases involving healthcare worker were reported in November.

Scarlet fever update (November 1, 2018 – November 30, 2018) Scarlet fever activity continued to increase in November. CHP recorded 208 cases of scarlet fever in November as compared with 162 cases in October.The cases recorded in November included 132 males and 76 females aged between 11 months and 41 years (median: five years). Among them, there was a fatal case. This case affected a 22-month-old boy with underlying illness. He had presented with fever, runny nose and cough since August 21. He was found to be unconscious at home on August 26 and was sent to the AED of a public hospital. He died on the same day. Blood specimen and splenic swab collected for culture during autopsy yielded Streptococcus pyogenes. Autopsy revealed that the cause of death was multilobar pneumonia due to scarlet fever. In November, there were nine institutional clusters occurring in six kindergartens/child care centres and three primary schools, affecting 21 children in total. In view of the elevated scarlet fever activity, parents have to take extra care of their children in maintaining strict personal, hand and environmental hygiene. Scarlet fever can be effectively treated with antibiotics. People presenting with symptoms of scarlet fever (such as fever, sore throat and skin rash) should consult a doctor promptly for early diagnosis and treatment. Besides, children suffering from scarlet fever should refrain from attending school or child care setting until fever has subsided and they have been treated with antibiotics for at least 24 hours.

COMMUNICABLE DISEASES WATCH 110 Dec 16 - Dec 29 2018 WEEKS 51 - 52 VOL 15 ISSUE NO 26

EDITORIAL BOARD Editor-in-Chief Dr SK Chuang Members DrYonnie Lam / Dr Albert Au / DrTYWong / Dr GladysYeung / Dr Benjamin FUNG / KK So / Sheree Chong / Doris Choi / Chloe Poon Production Assistant Yoyo Chu. This biweekly publication is produced by the Centre for Health Protection (CHP) of the Department of Health, 147C,Argyle Street, Kowloon, Hong Kong ISSN 1818-4111 All rights reserved Please send enquiries to [email protected].

FEATURE IN FOCUS Review of cryptosporidiosis in Hong Kong Reported by Miss Doris Choi, Scientific Officer, Enteric and Vector-borne Disease Office and Dr YH LEUNG, Senior Medical and Health Officer, Communicable Disease Division, Surveillance and Epidemiology Branch, CHP.

Cryptosporidiosis is a diarrhoeal disease caused by the parasite Cryptosporidium. Among the Cryptosporidium species, C. hominis and C. parvum cause the majority of human infections. Other species, such as C. canis, C. felis, C. meleagridis and C. muris, have also been reported to cause human infections1.

Cryptosporidiosis is transmitted through ingestion of faecal contaminated food or water, including pool water swallowed while swimming, or from person to person via the faecal-oral route. People infected with Cryptosporidium can be asymptomatic. For those who develop symptoms, the symptoms generally begin two to ten days after infection and include watery diarrhoea, abdominal pain, dehydration, nausea, vomiting, fever and weight loss. In immunocompetent people, the symptoms are usually self-limiting and last about one to two weeks. However, symptoms may be more severe and prolonged and can lead to serious or life-threatening illnesses in immunocompromised people such as patients with acquired immunodeficiency syndrome (AIDS) or inherited diseases that affect the immune system, cancer patients and transplant recipients who are taking immunosuppressive drugs2.

Cryptosporidiosis can be diagnosed by microscopic examination of stool samples using different techniques. Molecular methods can be used to identify Cryptosporidium at the species level3. The mainstay of management of cryptosporidiosis is to prevent dehydration by drinking adequate amounts of fluid while anti-diarrhoeal medicine may control diarrhoea. Most immunocompetent patients will recover without treatment4.

Due to its low infectious dose, prolonged survival in moist environments and high tolerance to chlorine, Cryptosporidium is highly transmissible through drinking or recreational water such as swimming pools5. Outbreaks of cryptosporidiosis linked to drinking municipal water or recreational water contaminated with Cryptosporidium have been reported in overseas countries.

Global situation The first human case of cryptosporidiosis was reported in 1976 in an immunocompetent child. In the 1980s, cryptosporidiosis emerged as an opportunistic infection that complicated AIDS and became widely recognised as a human pathogen causing acute enteric disease6,7. In the past two decades, cryptosporidiosis has become one of the most common causes of waterborne diseases and is now endemic worldwide, with the highest incidences in developing countries5.

The largest documented outbreak of cryptosporidiosis occurred in Milwaukee, Wisconsin of the United States in 1993. It affected more than 400 000 people and resulted in 54 confirmed deaths associated with cryptosporidiosis, of which, 85% had AIDS listed as the underlying cause of death8,9. The outbreak was due to contamination by Cryptosporidium of Lake Michigan water which was used as drinking water after treatment.The Cryptosporidium oocysts could not be adequately filtered at one of the water treatment plants, allowing the parasites to enter the drinking water supply, hence resulting in the outbreak8.

Local situation In Hong Kong, medical practitioners are encouraged to report cryptosporidiosis cases to the Centre for Health Protection (CHP) of the Department of Health for epidemiological investigations and implementation of control measures. In the past decade (2009-2018*), CHP recorded a total of 35 confirmed cryptosporidiosis cases, with the annual number ranged from zero to 15 (median: one case) (Figure 1). The 35 cases involved 21 males and 14 females, with ages ranging from nine to 56 years (median: 32 years).The majority of the patients were Chinese (30, 85.7%), followed by African (1, 2.9%), Belgian (1, 2.9%), British (1, 2.9%), French (1, 2.9%) and one was unknown due to loss of contact. All patients presented with diarrhoea (35, 100%). Other presenting symptoms included abdominal pain (29, 82.9%), fever (14, 40.0%) and nausea (13, 37.1%).Thirty-one patients (88.6%) required hospitalisation while 30 of them had been discharged with a median length of stay of three days (range: less than one day to 24 days). No fatal case due to cryptosporidiosis was recorded.

COMMUNICABLE DISEASES WATCH 111 Dec 16 - Dec 29 2018 WEEKS 51 - 52 VOL 15 ISSUE NO 26 Most cases (23, 65.7%) were locally acquired infections, while four (11.4%) were imported cases who acquired the infection from Kenya (1), Malaysia (1) and multiple countries (2) respectively.The place of infection could not be determined for six cases (17.1%) as the patients had stayed both in and outside Hong Kong during the incubation period.The importation status of the remaining two cases (5.7%) was unknown. No epidemiological linkage was identified among the cases.

About 46% (16) of the patients enjoyed good past health, while 12 (34.3%) were infected with human immunodeficiency virus, one (2.9%) was a renal transplant recipient, one had acute leukaemia (2.9%) while four (11.4%) had other underlying medical illnesses and the past health of one patient (2.9%) was unknown. Regarding the risk factors, two patients reported swimming and drinking unboiled water outside Hong Kong, Figure 1 - Annual number of confirmed cryptosporidiosis cases respectively. Three and one patients had consumed raw vegetables and recorded by CHP from 2009 to 2018 (*Preliminary as of December 31, 2018). raw oyster, respectively.

Notably, CHP has observed an upsurge of C. hominis infection since October 2018. From October 23 to December 20, CHP investigated a total of eight cases of C. hominis infection. The cases involved three males and five females with ages ranging from 15 to 51 years (median: 35 years). The patients were all immunocompetent with symptoms onset from October 6 to December 9 (Figure 2). The presenting symptoms were diarrhoea (8), abdominal pain (6) and fever (5). All patients had been hospitalised and seven out of eight were hospitalised at different wards of the same private hospital while the remaining one was hospitalised at another private hospital.All patients had stable condition and were discharged. Their stool specimens were tested positive for Cryptosporidium nucleic acid by the private hospital concerned and subsequently confirmed to be Figure 2 - Epidemic curve of the eight cases of C. hominis infection (preliminary positive for C. hominis by the Public Health Laboratory as of December 31, 2018). Services Branch of CHP.

CHP conducted extensive investigations attempting to identify the reason accounting for the upsurge. All cases had no known exposure history to recreational water or unboiled water. So far, no epidemiological linkage and common exposure among the cases could be identified. Review of patients’ practice of stool specimen collection and the procedures of laboratory diagnosis by the private hospital where seven of the patients had stayed were unremarkable. CHP is closely monitoring the situation.

Prevention of cryptosporidiosis There is no vaccine for cryptosporidiosis. To avoid contracting the disease, members of the public should maintain good personal, food and environmental hygiene, including the following:

✦ Adopt the Five Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases; ✦ Wash hands thoroughly with liquid soap and water before handling food or eating, and after using toilet or handling faecal matter; ✦ Drink only boiled water from the mains or bottled drinks from reliable sources; ✦ Avoid drinks with ice of unknown origin; ✦ Purchase fresh food from hygienic and reliable sources. Do not patronise illegal hawkers; ✦ Eat only thoroughly cooked food; ✦ Wash and peel fruit by yourself and avoid eating raw vegetables; ✦ Exclude infected persons and asymptomatic carriers from handling food and from providing care to children, elderly and immunocompromised people; and ✦ Refrain from work or school, and seek medical advice if suffering from gastrointestinal symptoms such as diarrhoea.

Further information on food safety can be found from the website of the Centre for Food Safety of the Food and Environmental Hygiene Department.

COMMUNICABLE DISEASES WATCH 112 Dec 16 - Dec 29 2018 WEEKS 51 - 52 VOL 15 ISSUE NO 26 References 1Centers for Disease Control and Prevention. Cryptosporidium: Pathogen & Environment. Available at: https://www.cdc.gov/parasites/crypto/pathogen.html, accessed on December 23, 2018. 2Centers for Disease Control and Prevention. Cryptosporidiosis: Illness & Symptoms. Available at: https://www.cdc.gov/parasites/crypto/illness.html, accessed on December 23, 2018. 3Centers for Disease Control and Prevention. Cryptospriodiosis: Diagnosis & Detection. Available at: https://www.cdc.gov/parasites/crypto/diagnosis.html, accessed on December 23, 2018. 4Centers for Disease Control and Prevention. Cryptosporidiosis:Treatment. Available at: https://www.cdc.gov/parasites/crypto/treatment.html, accessed on December 23, 2018. 5Centers for Disease Control and Prevention. Infectious Diseases Related to Travel. Available at: https://wwwnc.cdc.gov/travel/yellowbook/2018/infectious-diseases-related-to-travel/cryptosporidiosis, accessed on December 23, 2018. 6Centers for Disease Control and Prevention. Epidemiologic Notes and Reports Cryptosporidiosis: Assessment of Chemotherapy of Males with Acquired Immune Deficiency Syndrome (AIDS). Morbidity and Mortality Weekly Report (MMWR) [Internet]. 1982; 31(44): 589-92. 7O'Connor R M, Shaffie R, Kang G,Ward HD. Cryptosporidiosis in patients with HIV/AIDS.AIDS. 2011;25(5):549-60. 8Hoxie NJ, Davis JP, Vergeront JM, Nashold RD, Blair KA. Cryptosporidiosis-associated mortality following a massive waterborne outbreak in Milwaukee,Wisconsin.Am J Public Health. 1997;87(12):2032-5. 9Mac Kenzie WR, Hoxie NJ, Proctor ME, Gradus MS, Blair KA, Peterson DE, et al. A massive outbreak in Milwaukee of cryptosporidium infection transmitted through the public water supply. N Engl J Med. 1994;331(3):161-7.

Update on the situation of listeriosis in Hong Kong Reported by Dr Hyeon LEUNG, Medical and Health Officer, Enteric and Vector-borne Disease Office, Surveillance and Epidemiology Branch, CHP.

Facts on listeriosis Listeriosis is a primarily foodborne infection caused by the bacterium Listeria monocytogenes. L. monocytogenes is ubiquitous in nature and can be found in soil, water, sewage and vegetation1. It can contaminate a variety of foods and is able to tolerate adverse environmental conditions with low temperatures, high acidity and high salt concentrations2. As such, ready-to-eat products that have a long refrigerated shelf-life and are consumed without further listericidal treatment, such as cheese, unpasteurised milk, processed meat, smoked seafood, raw vegetables and salad, are considered high-risk1,3.

While the principal mode of transmission is through consumption of contaminated food, listeriosis may also be transmitted from pregnant women to their foetuses1. In otherwise healthy people, listeriosis usually manifests as febrile listerial gastroenteristis with self-limiting symptoms including diarrhoea, fever and headache. In the elderly and immunocompromised people, listeriosis may manifest as invasive listeriosis with fever, myalgia, sepsis and meningitis. In invasive listeriosis, symptoms are severe and the mortality rate is as high as 20 to 30%1. Pregnant women, the elderly and immunocompromised people are particularly at risk of contracting listeriosis4. Listeriosis in pregnant women can result in miscarriage, stillbirth, premature delivery and life-threatening infection of the newborn4. Severe cases such as meningitis should be treated with antibiotics1.

In Hong Kong, listeriosis is a notifiable disease under the Prevention and Control of Disease Ordinance (Cap 599). From 2009 to 2018, the Centre for Health Protection (CHP) of the Department of Health (DH) recorded a total of 179 cases of listeriosis. From 2009 to 2018, the annual number of cases ranged from six to 26 and the annual incidence ranged from 0.09 to 0.36 cases per 100 000 population (Figure 1). Cases were recorded all year round and there was no seasonal trend observed.

Among the 179 cases, 62 (34.6%) were male and 117 (65.4%) were female. Their ages ranged from less than one day to 95 years (median: 60 years).The incidences in infants and adults aged 65 years or above were higher than that of Figure 1 - Annual number of cases and incidence of listeriosis in Hong Kong, other age groups (Figure 2). 2009-2018.

The commonest presenting symptom was fever (156, 87.2%), followed by abdominal pain (30, 16.8%), chills/rigors (30, 16.8%), diarrhoea (30, 16.8%) and headache (28, 15.6%).Almost all patients (178, 99.4%) required hospitalisation. Seventeen patients died due to listeriosis, giving a case fatality rate of 9.5%. Among the 179 cases, 38 (21.2%) were pregnancy-related (i.e. affecting pregnant women or neonates) while the remaining 141 cases (78.8%) were non-pregnancy-related (Figure 3). COMMUNICABLE DISEASES WATCH 113 Dec 16 - Dec 29 2018 WEEKS 51 - 52 VOL 15 ISSUE NO 26 Among the 141 non-pregnancy-related cases, the majority (131, 92.9%) had at least one chronic medical condition.The commonest medical condition w a s m a l i g n a n c i e s ( 6 4 , 4 5 . 4 % ) . O t h e r immunocompromising conditions such as autoimmune diseases (27, 19.1%), renal diseases (27, 19.1%) and diabetes mellitus (25, 17.7%) were also documented. Seventy-nine patients (56.0%) in this group were aged 65 or above. There were 14 deaths due to listeriosis in this group, giving a case fatality rate of 9.9%.

Among the 38 pregnancy-related cases, 30 (78.9%) were pregnant women and eight (21.1%) were Figure 2 - Age-specific annual incidence of listeriosis in Hong Kong, 2009-2018. neonates. Among the 30 pregnant patients, six (20%) had foetal loss. Among the remaining 24 pregnant patients, five (20.8%) delivered live births with documented neonatal listeriosis, of which four were born preterm and three of these preterm neonates died due to listeriosis.Another two pregnant patients underwent preterm labour with their neonates born prematurely whom did not have . No fatal case was recorded among the pregnant patients. Among the eight cases of neonatal infection, five (62.5%) were born to mothers with listeriosis and the remaining three (37.5%) were born to mothers not diagnosed with listeriosis. As mentioned above, three of the infected neonates died due to Figure 3 - Annual number of pregnancy-related and non-pregnancy-related listeriosis listeriosis, giving a case fatality rate of 37.5%. cases, 2009-2018.

The high-risk food items most commonly consumed by the patients during the incubation period# were dairy products (106, 59.2%), followed by salad or sandwiches (39, 21.8%), cheese (29, 16.2%) and raw or smoked seafood (19, 10.6%).Among those who consumed dairy products, 70 (66.0%) had consumed milk, milk powder or soymilk and 26 (24.5%) had consumed ice-cream. One patient consumed cheese made with unpasteurised milk.

To prevent listeriosis, members of the public should maintain good personal, food and environmental hygiene. The risk of contracting listeriosis can be reduced by adopting the Five Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Te m p e r a t u r e ( Ke e p f o o d a t s a f e t e m p e r a t u r e ) . I n d i v i d u a l s a t r i s k , s u c h a s p r e g n a n t w o m e n , w o m e n p r e p a r i n g f o r p r e g n a n c y, infants, the elderly and immunocompromised people, should avoid consumption of high-risk foods. For more information on listeriosis, please visit the CHP website at: https://www.chp.gov.hk/en/healthtopics/content/24/14450.html. For healthy eating advice for pregnant women and women preparing for pregnancy, please visit the website of the Family Health Service of DH at: https://www.fhs.gov.hk/english/health_info/woman/20036.html.

#More than one item were consumed in some cases.

References 1World Health Organization. Listeriosis. [Fact sheet]. 2018. Available at: http://www.who.int/mediacentre/factsheets/listeriosis/en/, accessed on November 13, 2018. 2Codex. Guidelines on the Application of General Principals of Food Hygiene on the Control of Listeria monocytogenes in Foods CAC/GL 61. Geneva,Switzerland: Codex Alimentarius Commission; 2007. 3U.S. Food and Drug Administration. Quantitative Assessment of Relative Risk to Public Health from Foodborne Listeria monocytogenes Among Selected Categories of Ready-to-Eat Foods. 2003. 4Centers for Disease Control and Prevention. Listeria (Listeriosis). 2017. Available at: https://www.cdc.gov/listeria/symptoms.html, accessed on November 13, 2018.

COMMUNICABLE DISEASES WATCH 114 Dec 16 - Dec 29 2018 WEEKS 51 - 52 VOL 15 ISSUE NO 26 NEWS IN BRIEF

A possible case of sporadic Creutzfeldt-Jakob disease

On December 18, 2018, the Centre for Health Protection (CHP) recorded a possible case of sporadic Creutzfeldt-Jakob disease (CJD) affecting a 67-year-old woman with underlying illnesses. She had presented with unsteady gait and blurred vision since February 2017. She was found to have progressive dementia, gait disturbance, dysarthria, extrapyramidal dysfunction and cerebellar disturbance.The magnetic resonance imaging (MRI) of the brain showed extensive cortical abnormality suspicious of CJD. Subsequently she had multiple admissions to public hospitals for her medical conditions. She was last admitted to a public hospital on September 4, 2018 due to pneumonia. Her condition deteriorated and succumbed on October 9, 2018.The causes of death were pneumonia and CJD. She had no known family history of CJD and no reported risk factors for iatrogenic CJD. She was classified as a possible case of sporadic CJD.

A sporadic case of Streptococcus suis infection

On December 24, 2018, CHP recorded a sporadic case of Streptococcus suis infection affecting a 56-year-old man with good past health. He had presented with fever, headache and left calf pain since December 21. He attended the Accident and Emergency Department (AED) of a public hospital on December 21 and was admitted on the same day. The clinical diagnosis was left calf cellulitis. His blood specimen was tested positive for Streptococcus suis. He was treated with a course of antibiotics and his condition remained stable. The patient was a butcher. He had history of handling raw pork and right middle finger abrasion injury at work during the incubation period. He had no travel history during the incubation period. His home contacts and colleagues remained asymptomatic.

A sporadic case of necrotising fasciitis due to Vibrio vulnificus infection

On December 26, 2018, CHP recorded a sporadic case of necrotising fasciitis due to Vibrio vulnificus infection affecting a 60-year-old male with underlying illness. He had presented with fever, right foot pain and swelling since December 24. He attended the AED of a public hospital on December 25 and was admitted on the same day. The clinical diagnosis was necrotising fasciitis. He was treated with antibiotics and surgical debridement of right foot. Blood and right foot tissue fluid collected on December 25 were both tested positive for Vibrio vulnificus. His condition was stable. He recalled that his right foot was pricked by the fin of a sea bass (鱸魚) while visiting a wet market on December 24. He had no recent travel history.

A domestic cluster of pertussis

CHP recorded a domestic cluster of pertussis in mid-December 2018, affecting a one-month-old boy and his 63-year-old grandmother.The boy presented with productive cough on December 9 and attended a private doctor on December 12. His nasopharyngeal swab collected on December 12 was tested positive for Bordetella pertussis and he was then treated with azithromycin.The patient was subsequently hospitalised at a public hospital for cyanotic spells and post-tussive vomiting from December 17 to 19. His condition was all along stable.

Contact tracing revealed that his grandmother had on and off cough since November 30 and she was referred by CHP to a public hospital for management on December 14. Her pernasal swab collected on December 14 was tested positive for Bordetella pertussis. She was treated with azithromycin and did not require hospitalisation. Her condition was stable. Pernasal swab collected from the boy’s asymptomatic father was also tested positive for Bordetella pertussis while those collected from the other home contacts were negative. Chemoprophylaxis was given to all asymptomatic home contacts.

The two patients had no travel history during the incubation period.The boy was yet to receive the first dose of diphtheria, tetanus, acellular pertussis and inactivated poliovirus vaccine while the grandmother’s vaccination status against pertussis was unknown.

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