Hepatitis E virus in wild boar from Poland

Hepatitis E virus (HEV) is an emerging zoonotic pathogen of growing public health concern. HEV genotype 3 is a cause of sporadic human infections in Europe, and is carried by wild boars (Sus scrofa). This study investigated the prevalence of HEV in free-ranging wild boars from different regions of Poland and evaluated the potential risk factors associated with infection. Serum samples (n = 367) were tested serologically for HEV antibodies, and spleen samples (n = 100) for viral RNA using Real-Time quantitative RT-PCR. Detection rates were analysed in relation to geographic origin, sex, and age. HEV-IgG antibodies were detected in 154/367 (41.96%) samples. Viral RNA was identified in 10/100 animals, all of which also tested seropositive. Nested reverse-transcription PCRs amplifying short genomic fragments within ORF1 and ORF2 confirmed five viral sequences: one strain was classified as HEV-3c, related to a human strain from the Netherlands, while the other four belonged to an unclassified subtype similar to sequences reported in wild boar in Europe. Only wild boar density appeared to significantly influence HEV seropositivity. Positive animals were distributed across multiple voivodeships, suggesting widespread environmental circulation.