Molecular character analysis of Japanese encephalitis virus isolated from Sichuan province, China

Objective To analyze the genotype of Japaneso encephalitis virus (JEV) strains isola-ted in 2004 from mosquitoes collected in Bazhong city, Sichuan province of China, and the characters of amino acid in the PrM and E gene. Methods The isolated virus strains from mosquitoes were identified by biological, serological and molecular biology. PrM and E segments of the isolated JEV were amplified by RT-PCR, the PCR products were purified and sequenced. Multiple alignment, phylogenetic and amino acid (AA) analysis were carried out by Clustal X (1.8) , MEGA4 and GENEDOC (3.2) . Results The total of 4688 mosquitoes were collected including Armigeres and Culex. Six isolates were identified be-longing to genotype 1 JEV. The comparison between new genotype 1 JEV strains and live attenuated vaccine strain SA14-14-2 in PrM and E gene showed that total 3 sites amino acid differences in PrM gene and 14 sites in E gene, respectively. Three sites (PrM2, 64 and 65 ) in PrM protein and four sites (E129, 222,327 and 366) in E protein were only belonging to genotype 1 JEV. Conclusion The new isolated JEV strains in Sichuan province belong to genotype 1. It suggests that the vaccine strain SA14-14-2 currently used for preventing Japanese encephalitis is able to protect people against JEV, although in the segments of it had some amino acid differences between vaccine strain and the epidemic genotype 1 JEV strains in PrM and E gene.\r\n\r\nKey words: \r\nJapanese encephalitis virus; Genotype; Phylogeny