Seroprevalence and genetic characterization of zoonotic hepatitis E virus among swine in Beijing, China

Hepatitis E virus (HEV) is a major zoonotic pathogen widely circulating in swine, but contemporary data on its molecular epidemiology in swine populations in Beijing are limited. We investigated the seroepidemiological and molecular characteristics of HEV in swine in Beijing, China. A total of 1,018 serum samples collected from 21 swine farms were tested for anti-HEV IgG, and 991 bile samples from slaughtered pigs were screened for HEV RNA. HEV-positive samples were subjected to ORF1/ORF2 sequencing and phylogenetic analysis, and selected samples underwent near-complete genome sequencing and amino acid characterization. The overall seroprevalence was 21.81%, with variation observed across the surveyed farms. HEV RNA was detected in 4.74% of bile samples, and sequence data were successfully obtained from 41 samples. HEV-4 was the predominant genotype, with subtype 4a accounting for the majority of samples, followed by subtype 4d, whereas HEV-3a was detected at a lower frequency. No clear recombination signals were observed among the three near-complete genomes relative to the selected reference sequences. Amino acid analysis identified genotype-associated variation at RdRp residue 1634, whereas one substitution type (T497I) was identified within a reported neutralizing epitope of ORF2. These findings characterize the seroepidemiological and molecular features of HEV in swine sampled in Beijing and support continued genotype-resolved molecular surveillance.