Hepatitis E – Chad
From 1 September 2016 until 13 January 2017, a total of 693 cases including 11 deaths of acute jaundice syndrome (AJS) have been reported from Am Timan, Chad.
Of the 50 patients with AJS who were hospitalized, 48 were tested for Hepatitis E using the Hepatitis E virus rapid diagnostic test (HEV RDT) and 27 (56.3%) tested positive. In total, at the end of epidemiological week 2, 2017, a total of 126 HEV RDT have been performed, of them 57 (45.2%) were positive, while 69 (54.8%) tested negative for Hepatitis E. 18 (31.6%) of the 57 patients that tested positive using the HEV RDT also had a positive malaria test, and 20 (29%) out of 69 patients that tested negative using the HEV RDT also had a positive malaria test. Since September 2016, 11 deaths have been reported among the hospitalized cases but the total case fatality might be underestimated.
As of 13 January 2017, 16 pregnant women presenting with AJS have been hospitalized and tested for Hepatitis E, 12 (75%) of them tested positive using the HEV RDT. Of the pregnant women presenting with AJS, four have reportedly died (three had tested positive for Hepatitis E).
Approximately 90% of the AJS cases were reported from Am Timan which appears to be the epi-centre of the ongoing outbreak, and most of the cases are identified through active case findings. As of 13 January 2017, AJS cases have been reported from 59 different quartiers in and surrounding Am Timan.
Public health response
The outbreak was detected when two pregnant icteric women were admitted in the Am Timan Regional Hospital, partly supported by Médecins Sans Frontières (MSF) since 2009. MSF has been responding to the outbreak in support to the Ministry of Public Health (MPH) with a total of 14 expatriate staff and over 400 national staff dedicated to the epidemic response in addition to staff involved in the regular project. MSF provides support in implementing outbreak monitoring, active surveillance, water chlorination and community sensitization in Am Timan.*
In addition, World Health Organization (WHO) and the MPH are complementing the initial investigations carried out between 22–29 October 2016 by extending investigations to the whole region in order to identify potential new foci.** WHO country office is also supporting the MPH in passive and active surveillance strengthening outside of Am Timan, developing case definition, surveillance tools, simple case management protocols and testing algorithm, defining criteria for case hospitalization and carrying out needs assessment in and outside the town of Am Timan. WHO is also advocating for additional needed partnerships especially to address the needs in terms of water and sanitation and social mobilisation in Am Timan as in the region.***
WHO risk assessment
Based on the available information, there appears to be a plateau in the number of cases reported in the past 5 weeks from the affected area with an average of 70 cases reported weekly where only a minor proportion (7.2%) requires hospitalization. The infectious risk seems confined to Am Timan and immediate surroundings. However, the event remains under close monitoring at all levels of WHO. The current level of risk for further spread remains as moderate to high and at local level, and the limited capacity to respond to date calls for additional immediate support, especially in terms of water and sanitation and social mobilisation.
WHO recommends the continuation of the investigations with a specific case definition as to describe the time, place and person characteristics of the outbreak and identify the source. It is important to identify the source of contamination of the surface water and, in the meantime, to ensure water safety by chlorination at the point of use by the population. Travellers to Chad should follow standard hygiene recommendations in terms of water and food safety for travellers. These should protect them against Hepatitis E, as the risk of person to person transmission is very low.
*Please note that the first paragraph under the heading "Public health response" was added on 30 January 2017. **Please note that an amendment was made to this sentence on 30 January 2017 to add additional information regarding the investigations carried out during October 2016. ***Please note that an amendment was made to this sentence on 30 January 2017 to add additional contextual information regarding the needed partnerships.