Belgian wildlife as potential zoonotic reservoir of hepatitis E virus

Hepatitis E is an acute human liver disease in healthy individuals but may become chronic. It is caused by the hepatitis E virus (HEV) and can have a zoonotic origin.
In this study, 383 sera from wild boars were selected for serology; for virology, 69 sera and 61 livers from young wild boars were used. A total of 189 and 235 sera of respectively red and roe deer were collected for serological analysis. For virology, 84 and 68 sera and 29 and 27 livers from respectively red and roe deer were sampled.
An apparent seroprevalence of 34% was found in wild boars, 1% in red deer and 3% in roe deer.
In order to assess the ELISA screening prevalence, Western blot (WB) analyses and a ROC curve analysis were performed. Different scenarios with varying ELISA specificities relative to WB were analysed. In wild boar, seroprevalence remained high whatever the scenario; 4 out of 69 sera and 4 out of 61 livers were detected as positive for HEV RNA. All sequences obtained from sera belonged to genotype HEV-3. HEV RNA, belonging to genotype HEV-3, was detected in one red deer liver.
Wild boar can be considered as a host reservoir of the virus in Belgium. However, the low prevalence in deer makes these species an unlikely reservoir. This evidence needs further investigation in order to determine in which situation deer can serve as reservoir and raise the question of the dynamics of HEV infection between wild fauna, domestic pigs and humans.