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Background: In September 2016, three acutely jaundiced (AJS) pregnant women were admitted to Am Timan Hospital, eastern Chad. We described the outbreak and conducted a case test-negative study to identify risk factors for this genotype of HEV in an acute outbreak setting. Methods: Active case finding using a community based surveillance network identified suspected AJS cases. Pregnant or visibly ill AJS cases presenting at hospital were tested with Assure® IgM HEV rapid diagnostic tests (RDTs) and some with Polymerase Chain Reaction (PCR) in Amsterdam; confirmed cases were RDT-positive and controls were RDT-negative. All answered questions around: demographics, household makeup, area of residence, handwashing practices, water collection behaviour and clinical presentation. We calculated unadjusted odds ratios (ORs) and 95% confidence intervals (95% CI). Results: Between September and April 2017, 1443 AJS cases (1293 confirmed) were detected in the town(attack rate: 2%; estimated 65,000 population). PCR testing confirmed HEV genotype 1e. HEV RDTs were used for 250 AJS cases; 100 (40%) were confirmed. Risk factors for HEV infection, included: having at least two children under the age of 5 years (OR 2.1, 95%CI 1.1–4.3), having another household member with jaundice (OR 2.4, 95%CI 0.90–6.3) and, with borderline significance, living in the neighbourhoods of Riad (OR 3.8, 95%CI 1.0–1.8) or Ridina (OR 3.3, 95%CI 1.0–12.6). Cases were more likely to present with vomiting (OR 3.2, 9%CI 1.4–7.9) than controls; possibly due to selection bias. Cases were non-significantly less likely to report always washing hands before meals compared with controls (OR 0.33, 95%CI 0.1–1.1). Discussion: Our study suggests household factors and area of residence (possibly linked to access to water and sanitation) play a role in HEV transmission; which could inform future outbreak responses. Ongoing sero-prevalence studies will elucidate more aspects of transmission dynamics of this virus with genotype 1e. [ABSTRACT FROM AUTHOR]

Background: From September 2016-April 2017, Am Timan, Chad, experienced a large HEV outbreak in an urban setting with a limited impact in terms of morbidity and mortality. To better understand HEV epidemiology in this context, we estimated the seroprevalence of anti-HEV antibodies (IgM and IgG) and assessed the risk factors for recent HEV infections (positive anti-HEV IgM) during this outbreak.Methods: A serological survey using simple random sampling was implemented in Am Timan at the tail-end of the outbreak (sample size aim = 384 household). Household members provided us with blood samples and household heads answered questions around water, sanitation and hygiene practices and animal ownership. Blood samples were tested for HEV IgG and IgM antibodies using Enzyme-Immune-Assay (EIA). We calculated weighted prevalence estimates and prevalence ratios (PRs) for possible risk factors for recent infection using multivariate Cox regression.Results: We included 241 households (1529 participants). IgM prevalence decreased with age: 12.6% (< 5 years) to 4.3% (> 15 years). IgG prevalence increased with age: 23.5% (< 5 years) to 75.9% (> 15 years). Risk factors for recent HEV infections included: sharing the sanitation facility with other HHs (PR 1.72; 95%CI: 1.08-2.73), not systematically using soap for HW (PR 1.85; 95%CI: 1.30-2.63) and having animals sleeping inside the compound (PR 1.69; 95%CI: 1.15-2.50).Conclusions: Evidence suggests that Am Timan was already highly endemic for HEV before the outbreak, potentially explaining the limited extent of the outbreak. Recent infection with HEV was linked to household level exposures. Future HEV outbreak response must include ensuring access to safe water, and reducing household level transmission through active hygiene and sanitation promotion activities. [ABSTRACT FROM AUTHOR]

Hepatitis E Virus (HEV) genotype 1 and 2 infect an estimated 20 million people each year, via the faecal-oral transmission route. An urban outbreak of HEV occurred in Am Timan, Chad, between September 2016 and April 2017. As part of the outbreak response, Médecins Sans Frontières and the Ministry of Health implemented water and hygiene interventions, including the chlorination of town water sources. We aimed to understand whether these water treatment activities had any impact on the number of HEV infections, using geospatial analysis of epidemiological and water treatment monitoring data. By conducting cluster analysis we investigated whether there were areas of particularly high and low infection risk during the outbreak and explored the reasons for this. We observed two high-risk spatial clusters of suspected cases and one high-risk cluster of confirmed cases. Our main finding was that confirmed HEV cases had a higher median number of days of exposure to unsafe water compared to suspected and non-confirmed cases (Kruskal-Wallis Chi Square: 15.5; p < 0.001). Our study confirms the mixed, but shifting, transmission routes during this outbreak. It also highlights the spatial and temporal analytical methods, which can be employed in future outbreaks to improve understanding of HEV transmission.

In September 2016, Médecins Sans Frontières responded to a hepatitis E (HEV) outbreak in Chad by implementing water treatment and hygiene interventions. To evaluate the coverage and use of these interventions, we conducted a cross-sectional study in the community. Our results showed that 99% of households interviewed had received a hygiene kit from us, aimed at improving water handling practice and personal hygiene and almost all respondents had heard messages about preventing jaundice and handwashing. Acceptance of chlorination of drinking water was also very high, although at the time of interview, we were only able to measure a safe free residual chlorine level (free chlorine residual (FRC) ≥0.2 mg/L) in 43% of households. Households which had refilled water containers within the last 18 hours, had sourced water from private wells or had poured water into a previously empty container, were all more likely to have a safe FRC level. In this open setting, we were able to achieve high coverage for chlorination, hygiene messaging and hygiene kit ownership; however, a review of our technical practice is needed in order to maintain safe FRC levels in drinking water in households, particularly when water is collected from multiple sources, stored and mixed with older water.