Hepatitis E Virus in Wild Boar in Northwest Poland: Sensitivity of Methods of Detection

In northwest Poland, 163 blood and 53 fecal samples of wild boars were collected in winter 2012/13 and 2013/14. All blood samples were tested for the presence of hepatitis E virus (HEV) ribonucleic acid (RNA) by two reverse transcription-polymerase chain reaction (RT-PCR) based methods and by anti-HEV IgG enzyme-linked immunosorbent assay (ELISA). About 17.2% of blood samples were seropositive. One-step nested RT-PCR turned out to be too insensitive (11.6% were positive). Therefore a two-step nested RT-PCR was applied where 25.8% of the blood samples were tested positive for HEV RNA. About 50.0% of blood samples positive in ELISA were also positive in two-step nested RT-PCR. The prevalence of HEV RNA in feces was 9.4%. Based on the results of blood (ELISA, PCR) and fecal (PCR) tests, the overall prevalence of HEV in wild boars in northwest Poland was 36.8%. There was no correlation between the ELISA results and the presence of HEV RNA in plasma or in feces. According to the sequencing results of 348 bp PCR products of HEV, there were four different subtypes identified. Reports on the prevalence of HEV in wild boar populations are varying due to different sensitivities of the detection methods. However, this study reveals based on a highly sensitive method that HEV is widely spread in wild boar populations in the northwestern region of Poland and posing a potential risk to the consumer of game meat.