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 E 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 disease caused by infection of the hepatitis E (HEV). HEV is a single-stranded RNA virus and has at least four genotypes, namely, genotypes 1 to 4. While genotypes 1 and 2 have only been found in humans, genotypes 3 and 4 viruses circulate in several animals (including , 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 . 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 products, organ transplant and vertical transmission from a pregnant woman to her foetus.

The 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 that goes undiagnosed. Typical of HEV infection include fever, reduced appetite, , 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 , 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 worldwide, leading to an estimated 3.3 million symptomatic cases of HEV infection every year1. HEV infections are most common in East and South .

In Hong Kong, (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 (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), (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 and pig liver during the incubation period, respectively. Among those who consumed pig liver, 19 and seven consumed it with hotpot and congee, 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 mussels (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 and water safety. The risk of hepatitis E infection can be reduced by adopting the Five Keys to 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 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 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 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, veterinarians, 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 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 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 yogurt 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.

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