A novel genotype of hepatitis E virus prevalent among farmed rabbits in China

In total, 335 serum samples were collected from rabbits from two farms in Gansu province, China, and tested for anti-hepatitis E virus (HEV) antibody using EIA and for HEV RNA using nested RT- PCR with ORF2 primers. The overall prevalence of anti-HEV antibody and HEV RNA was 57.0% (191/335) and 7.5% (25/335), respectively. The positivity rate of HEV RNA in the anti-HEV antibody negative group (7.6% (11/144)) did not differ significantly from that in the positive group (7.3% (14/191)). The concordance between HEV RNA and anti-HEV antibody was 43.3% with no significant correlation (P < 0.05). All 25 amplicons from the ORF2 region were cloned and sequenced. On the basis of nucleotide sequence comparison, they had 84-99% identity to each other and 73-77%, 70-76%, 75-82%, 71-77%, and 53-65% with the corresponding regions of genotypes 1, 2, 3, 4, and avian HEV, respectively. Samples that were positive with the ORF2 primers were amplified using ORF1 region primers; 17 were positive and shared 71-78%, 73-76%, 74-82%, 72-78%, and 39-58% identity with the corresponding regions of genotypes 1, 2, 3, 4, and avian HEV, respectively, at the nucleotide level. Two representative full-length sequences were determined. These two sequences shared 85% identity with each other and had 74%, 73%, 78-79%, 74-75%, and 46-47% identity to full-length genotypes 1, 2, 3, 4, and avian HEV, respectively. Thus, the sequences isolated from the rabbits represent a novel genotype of HEV. This study provides novel information about HEV genotypes infecting rabbits as well as evidence of a new mammalian genotype of HEV.