Prevalence of hepatitis E virus in swine under different breeding environment and abattoir in Beijing, China

This study was to investigate the prevalence of HEV in pig herds under different breeding environment and in abattoirs located in Beijing, China. In total 638 sera samples and 114 liver samples were collected for a serological survey and a RT-PCR assay, respectively. The average prevalence rate of HEV in pig herds in Beijing suburb were 47.5-100%. Seropositive rate was 76.6% for pig herds of large-scale and 90% for family-scale farms. For sera samples collected from abattoir, 127 samples (78.4%) were found to be positive. Among four liver samples (3.5%) that positive for HEV RNA detection, two strains of HEV has been identified. the two detected HEV sequences shared 99.1% nucleotide sequence identity with each other, and 76.4-81.0%, 76.5-76.8%, 75.7-79.0% and 85.2-96.4% with related strains representing genotype 1, 2, 3, and 4, respectively. Further phylogenetic analysis revealed two HEV sequences belonged to genotype 4 and exhibited a high identity with strain JKO-ChiSai98C (95.4 and 95.7%), and with strains 87, 277 and 292 (96.1-96.4%) isolated from patients with sporadic acute hepatitis E in Beijing, China. The results of this study indicated that the prevalence of HEV in the pig herds were quite high. Additional public-health concerns might be placed on pork safety.