Hepatitis E virus (HEV) genotype and the prevalence of anti-HEV in 8 species of animals in the suburbs of Beijing / 中华流行病学杂志

ABSTRACT

Objective To investigate the prevalence of anti-hepatitis E virus (HEV) and genotypes of hepatitis E virus in 8 species of animals including swine, cattle, sheep, horse, donkey, dog, chicken and duck in the suburb of Beijing. Methods Serum samples were collected from the 8 species of animals, and fecal samples of younger swine were collected from 2 stock farms. Anti-HEV was detected by Double Antigen Sandwich Assay. HEV RNA from fecal samples was detected by a reverse transcription nested polymerase chain reaction (RT-nPCR). Parts of the PCR products were cloned and sequenced. The swine HEV sequences were analyzed genetically. Results The positive rates of anti-HEV in serum specimens of swine, cattle, horse, donkey, sheep, dog, duck and chicken were 80.43%(481/598), 15.02%(52/346), 14.29%(40/280) ,0(0/26) ,9.88%(33/334), 0(0/ 21) ,3.03% (7/231) and 2.53%(8/316), respectively. The anti-HEV prevalence of adult swine(≥6 months)and younger swine(≤3 months)were 87.86%(369/420)and 62.92%(112/178)respectively. 74 of 111 (66.67% ) pig faces were positive for HEV RNA. Sequence analysis on these positive samples showed that there were 6 groups of HEV designated as bjsw1, bjsw2, bjsw3, bjsw4, bjsw5 and bjsw6. The 6 strains of HEV shared 94.5%-99.6% sequence identity of partial HEV ORF2 nucleotide with each other. The identities of HEV ORF2 nucleotide sequences between the 6 strains and genotype 1, 2, 3 and 4 were 75.6%-78.6% , 75.6%-76.2%, 77.1%-80.7% and 83.7%-94.5%, respectively. The sequence identity between the 6 strains and human HEV genotype 4d was 90.0%-94.5% . Conclusion HEV infection was seen in swine, cattle, horse, sheep, duck and chicken in the suburbs of Beijing. The anti-HEV positive rate appeared the highest in swine and the lowest in dog and donkey. The six strains of HEV isolated from younger swine belonged to genotype 4d.