[Analysis of sequence and genotype of E gene of the newly isolated Japanese encephalitis virus strains in Wuhan, Hubei Province].

ABSTRACT

OBJECTIVE: To analyze the molecular characteristics of the newly isolated two Japanese encephalitis virus strains (JEV) in Wuhan. METHODS: The mosquitoes were collected in Wuhan from April to October in 2009. The envelope (E) protein gene of JEV was detected using RT-PCR and sequenced. Sequence comparisons and phylogenetic analysis were conducted using DNAstar and MegAlign. RESULTS: Two Japanese encephalitis virus (JEV) strains (WHJX09-9, WHJX09-10) were isolated from Culex tritaeniorhynchus among 16 mosquito pools and identified as genotype I. The result showed that the homology of the two strains was 98. 9% in nucleotides and 100% in deduced amines. The comparison between the new genotype 1 JEV strains and live attenuated vaccine strain SA14-14-2 in E gene showed that the homology of nucleotide sequence was 87.4% and 87.9%, the homology of amino acid was 96.9% (total 15 amino acid were different) in E gene. The mutation sites of amino acid distributed among three different coding domain, but no antigen binding site and neurotoxin-involved site of amino acid were changed. CONCLUSION: Wuhan had appeared a new genotype of JEV which was different from the former strain isolated in Wuhan, the new JEV strains still had neurotoxicity but had high homology with the vaccine strains adopted in Wuhan. The vaccine could still be adopted to prevent Japanese encephalitis if steps were take to eradicate mosquitos at the same time. laboratory surveillance were also an important task to build an early-warning mechanism against JEV.