Isolation and phylogenetic analysis of Japanese encephalitis virus in Liaoning province

ObjectiveTo isolate and identify genetype of Japanese encephalitis virus(JEV)from mosquitoes collected in Liaoning province in 2007.MethodsVirus strains were isolated by inoculating BHK-21 cells.The isolated strains causing cytopathogenic effect(CPE)on cells were identified by reverse transcription polymerase chain reaction(RT-PCR).The RTPCR-products were sequenced and phylogenetic tree was constructed by neighbor-joining method in Mega3.1 software.ResultsTwenty-two strains were isolated and results of RT-PCR showed all strains were J EV.Sequence analysis of three virus selected showed the isolates belonged to genotype Ⅰ and the homology of nucleotide and amino acid sequence of E gene coding domain were 99.3% and 100%.Compared with the vaccine strain SA14-14-2,the divergence of amino acid sequence was twelve.ConclusionThe isolated strains from mosquitoes belonged to genetype Ⅰ and the divergence E-327(S→T)of domain revealed variant strain of JEV was first isolated in Liaoning province.