Detection of antibodies and nucleic acid of hepatitis E virus in pregnant women in Zhejiang Province / 中华传染病杂志

ABSTRACT

Objective To analyze the hepatitis E virus (HEV) infection status and the molecular characteristics of HEV isolated from pregnant women in Zhejiang Province.Methods Totally 98 236 serum samples collected from pregnant women during the year 2013 to 2015 were tested for HEV IgM by enzyme-linked immunosorbent assay (ELISA) and samples positive for IgM were detected for nucleic acid of HEV by nested polymerase chain reaction (PCR).The whole gene of HEV open reading frame 2 (ORF2) was further amplified and the prevalence was analyzed in nucleic acid-positive samples.Results Three hundred and fifty-two out of 98 236 serum samples were tested positive for HEV IgM,with positive rate of 0.36％.All the samples were simple positive of HEV IgM except for two samples co-infected with hepatitis B virus.HEV specific nucleic acid fragments were detected positive from three serum samples.Further phylogenetic analysis revealed that all the three HEV isolates in this study belonged to HEV genotype 4.Three isolates did not cluster in one branch,although they shared high nucleic acid homology and more than 97 ％ of amino acid homology.Variations were found significantly between sample sequence and other published HEV 4 isolates,including two variable regions found in the ORF2 gene (1-460 nucleotide and 620-870 nucleotide).However,the synonymous and non-synonymous substitutions rates in the two regions were similar,and neutral selection was the main evolutionary pressure.Conclusions HEV infection rate in pregnant women of Zhejiang Province is similar with the published data.The HEV isolates obtained in this study belong to genotype 4 with high variation rate.