Molecular characterization of hepatitis E virus detected in swine farms in the province of Quebec.

Swine Hepatitis E virus (HEV) could be a zoonotic agent for HEV infection in humans. In Canada, approximately 60% of 6-mo-old commercial pigs are seropositive for HEV; the prevalence is higher in the provinces of Quebec and Ontario. A study was set up to evaluate the presence of swine HEV in Quebec farms and to compare the strains detected in fecal samples with human and swine HEV strains reported worldwide. Fecal samples were collected randomly from May 2003 to January 2004 from 70 swine farms in Quebec. In 24 specimens, representing 34% of the visited farms, HEV RNA was extracted and detected by nested reverse-transcription polymerase chain reaction (RT-PCR). All amplified nested RT-PCR products were purified, cloned, and sequenced. The nucleotide sequences of a 304 base pair fragment at the 5' end of the open reading frame 2 gene were determined. Phylogenetic analysis revealed that the 24 amplified fragments clustered in genotype 3 and had 85% to 99% nucleotide-sequence similarity with HEV strains identified in Japan, the United States, and Canada. Three strains identified in the study (swSTHY1, swSTHY31, and swSTHY47) showed 95% homology with 2 Japanese (swJ1-1 and HE-JA10) and 1 American (US1) HEV human strains.