Occurrence of water-borne enteric viruses in two settlements based in Eastern Chad: analysis of hepatitis E virus, hepatitis A virus and human adenovirus in water sources.

Hepatitis E virus (HEV) is a common cause of water-borne acute hepatitis in areas with poor sanitation. In 2004 an outbreak of HEV infection affected around 2,000 people in Eastern Chad (Dar Sila). This paper describes the decrease in the incidence of acute jaundice syndrome (AJS) from 2004 until 2009 when a mean incidence of 0.48 cases/1,000 people/year was recorded in the region. Outbreaks of AJS were identified in some of the camps in 2007 and 2008. Moreover, water samples from drinking water sources were screened for human adenoviruses considered as viral indicators and for hepatitis A virus and HEV. Screening of faecal samples from donkeys for HEV gave negative results. Some of the samples were also analysed for faecal coliforms showing values before disinfection treatment between 3 and >50 colony forming units per 100 mL. All water samples tested were negative for HEV and HAV; however, the presence of low levels of human adenoviruses in 4 out of 16 samples analysed indicates possible human faecal contamination of groundwater. Consequently, breakdowns in the treatment of drinking water and/or increased excretion of hepatitis viruses, which could be related to the arrival of a new population, could spread future outbreaks through drinking water.