Global Task Force on Cholera Control (GTFCC) Surveillance Working Group

Global Task Force on Cholera Control (GTFCC) Surveillance Working Group

Interim Guidance Document on Cholera Surveillance Global Task Force on Cholera Control (GTFCC) Surveillance Working Group June 2017 Global Task Force on Cholera Control (GTFCC) Surveillance Working Group Table of contents 1. Introduction 4 2. Definitions 5 2.1. Cholera endemic area, cholera hotspot, cholera outbreak, cholera alert and cholera elimination 5 2.2. Cholera case definitions 6 3. Surveillance of cholera disease 7 3.1. Indicator-Based Surveillance 7 3.2. Event-Based Surveillance 8 3.3. Community-Based Surveillance 9 3.4. Environmental surveillance 10 4. Outbreak detection and response 11 5. Laboratory testing 13 5.1. Stool culture, PCR and Rapid Diagnostic Test 13 5.2. Collection, transport and storage of samples 14 5.3. Testing strategies 15 6. Data collection and reporting 17 6.1. Data collection tools 17 6.2. Reporting and flow of information 17 7. Data analysis and indicators 20 7.1. Description of cases by time, place and person 20 7.2. Surveillance indicators 21 7.3. Other indicators 23 7.4. Impact assessment 23 8. Surveillance in at-risk areas 25 8.1. Surveillance after outbreaks in highly endemic areas 25 8.2. Surveillance in complex emergencies situations 26 9. Bibliography 27 Annex 1. Example of data collection form for cholera cases 28 Annex 2. Template of a line-listing 30 Annex 3. Example of a weekly community-based surveillance form 31 2 Global Task Force on Cholera Control (GTFCC) Surveillance Working Group Foreword Cholera remains a global threat to public health and a key indicator of lack of social development. Cholera transmission is closely linked to inadequate access to clean water and sanitation. Typical at-risk areas include peri-urban slums and rural areas where basic infrastructure is not available, as well as camps for internally displaced persons or refugees, where living conditions and access to water and sanitation systems are disrupted. In 2015, more than 170,000 cases and 1300 deaths (CFR: 0.8%) were notified to WHO from 42 countries, of which 41% was reported from Africa 37% from Asia and 21% from Hispaniola. However, the true number of cholera cases occurring globally is thought to be much higher. Factors contributing to underreporting of cases and deaths may include weak surveillance systems, inconsistencies in case definitions, lack of laboratory diagnostic capacities, fear of negative impact on travel and trade, etc. An operational surveillance system for cholera is crucial for detecting outbreaks, monitoring disease occurrence and estimating disease burden to orient implementation of prevention and control measures and to allocate resources. The objective of this guidance document is to support the public health professionals in implementing effective surveillance of cholera in at-risk, endemic and epidemic areas. This document has been developed by the Surveillance Working Group of the Global Task Force for Cholera Control (GTFCC) at the World Health Organization based on the existing documents, guidelines, tools and articles related to surveillance of cholera disease, as well as technical discussions with experts held during GTFCC meetings. The document is aimed at health professionals working at Ministries of Health, Public Health Institutes, WHO Country Offices and partners who are involved in cholera surveillance. This interim version will be regularly updated. Acknowledgement is given to all members of the Surveillance Working Group of the GTFCC, experts and partners who have actively participated in the development of this guideline. 3 Global Task Force on Cholera Control (GTFCC) Surveillance Working Group 1. Introduction Cholera can be predicted, prevented, and treated. Areas with poor sanitation, limited access to safe water and deficient hygiene practices are considered at high risk for cholera transmission. In addition, limited access to health care facilities and inadequate treatment of cases are factors associated with high cholera-related mortality. Long term multi-sectoral prevention and control strategies ensuring adequate access to water and sanitation, social mobilization for health and hygiene promotion, immunization, surveillance, and rapid appropriate case management are essential for reducing the morbidity and mortality of cholera in endemic and epidemic contexts. An effective surveillance system aims to provide reliable and timely data to detect outbreaks in both endemic and non-endemic areas, monitor morbidity and mortality trends, and identify hotspots in areas where cholera disease is endemic, in order to implement adequate control measures to minimise the impact of the disease in the population. In addition, well-performing laboratories contribute to surveillance through timely and accurate testing of samples to confirm or discard Vibrio cholerae as the causative agent, to monitor the outbreak, and to characterise and determine antibiotic susceptibility of the circulating V cholerae strains. For cholera, key factors for effective surveillance include existence of a standard case definition, simple data collection tools, clear reporting procedures, analysis plans, rapid diagnosis of suspected cases and laboratory confirmation, routine feedback of surveillance data, and appropriate coordination at all levels of the public health sector (i.e. community, health facility, district, national, and international levels). In this line, activities for strengthening and improving the surveillance of cholera in a specific area or country should focus on providing to health professionals clear guidance on standard case definitions, data collection and reporting procedures, ensuring laboratory capacity to detect and confirm cholera, and involving all key actors and community for early detection and response effectively to outbreaks. 4 Global Task Force on Cholera Control (GTFCC) Surveillance Working Group 2. Definitions 2.1. Cholera case definitions Acute watery diarrhoea (AWD) Acute watery diarrhoea is an illness characterized by 3 or more loose or watery (non- bloody) stools within a 24-hour period. Suspected cholera case In areas where a cholera outbreak has not been declared: Any patient aged 2 years and older presenting with acute watery diarrhoea and severe dehydration or dying from acute watery diarrhoea. In areas where a cholera outbreak is declared: any person presenting with or dying from acute watery diarrhoea. Confirmed cholera case A suspected case with Vibrio cholerae O1 or O139 confirmed by culture or PCR and, in countries where cholera is not present or has been eliminated, the Vibrio cholerae O1 or O139 strain is demonstrated to be toxigenic. 2.2 Cholera endemic area, cholera hotspot, cholera outbreak, cholera alert and cholera elimination Cholera-endemic area An area where confirmed cholera cases, resulting from local transmission, have been detected in the last 3 years. An area can be defined as any subnational administrative unit including state, district or smaller localities. Note: Any country that contains one or more subnational administrative units that are endemic, as defined above, is considered a cholera-endemic country. Cholera hotspot A geographically limited area (e.g. city, administrative level 2 or health district catchment area) where environmental, cultural and/or socioeconomic conditions facilitate the transmission of the disease and where cholera persists or re-appears regularly. Hotspots play a central role in the spread of the disease to other areas. 5 Global Task Force on Cholera Control (GTFCC) Surveillance Working Group Cholera outbreak A cholera outbreak is defined by the occurrence of at least one confirmed case of cholera and evidence of local transmission. Outbreaks can also occur in areas with sustained (year-round) transmission, and are defined as an unexpected increase (in magnitude or timing) of suspected cases over two consecutive weeks of which some are laboratory confirmed. Such increases should be investigated and responded to appropriately through additional outbreak response and control measures. Cholera alert A cholera alert is defined by the detection of: two or more people aged 2 years and older (linked by time and place) with acute watery diarrhoea and severe dehydration or dying from acute watery diarrhea from the same areas within one week of one another OR (b) One death from severe acute watery diarrhoea in a person at least 5 years old OR (c) One case of acute watery diarrhoea testing positive for cholera by rapid diagnostic test (RDT) in an area (including those at risk for extension from a current outbreak) that has not yet detected a confirmed case of cholera. Cholera elimination Any country that reports no confirmed cases with evidence of local transmission for at least 3 consecutive years and has a well-functioning epidemiologic and laboratory surveillance system able to detect and confirm cases. 6 Global Task Force on Cholera Control (GTFCC) Surveillance Working Group 3. Surveillance of cholera disease An effective surveillance system is crucial for detecting outbreaks and for monitoring trends of disease over time. The surveillance system should aim to collect reliable and timely data to identify vulnerable populations and high risk areas to guide preventive and control measures including improving access to safe water and sanitation, health and hygiene education in the community, immunization of at-risk population, and adequate and timely access to patient care. However, detection and reporting of cholera cases is usually hampered by inadequate access to healthcare, deficient training in

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