Hepatitis E virus in pigs at the moment of slaughter in Spain, 2015 and 2017

We investigated the presence of hepatitis E virus (HEV) in pigs at the moment of slaughter in Spain in years 2015 and 2017. A total of 1786 caecal content, liver, and serum samples from animals at slaughterhouses were tested by reverse transcription real-time quantitative PCR (RT-qPCR) and anti-HEV antibodies were evaluated in 623 serum samples by an ELISA test. The overall seroprevalence obtained was 70.9 %. A total of 398 RT-qPCR positive samples were identified in caecal content (26.8 %; 156/583), serum (21.8 %; 136/623) and liver (18.3 %; 106/580). A total of 32 RT-qPCR positive samples were genotyped; 3f (84.4 %) and the 3c (9.4 %) being the most prevalent subgenotypes. This is the first report on detection of HEV in pigs at the moment of slaughter with a Spain nation-wide representation. The data show a large high seroprevalence (70.9 %) in pigs, while the presence of the virus (HEV RNA) was significantly lower. HEV RNA detection varied markedly between matrices, with caecal samples showing higher positivity (30-50 %) than serum (5-25 %); both simple and interaction GEE models confirmed strong effects of sample type and its interaction with year on prevalence estimates. However, the percentage of positive liver samples (18.3 %) and the concurrence between the HEV 3 subtypes identified (3f, 3m and 3c) and those identified in human patients in Spain, underscores the possibility of foodborne zoonosis. It can represent a real risk for consumers if pork products are not cooked adequately. A holistic One-Health approach, including a better understanding of HEV prevalence in the swine population, would allow implementation of control measures in the meat chain to mitigate the main transmission routes for humans.