云南省南部地区蚊携带乙型脑炎病毒的检测和遗传进化分析

Detection and Phylogenetic Analysis of Japanese Encephalitis Virus Carried by Mosquitoes in the Southern Area of Yunnan Province

为探索云南省南部地区乙型脑炎病毒(JEV)的流行及基因变异情况,将2016年8—10月在南部4个县级地区采集的6 952只蚊,根据采集地和蚊种合并为69份样品,采用RT-PCR检测JEV并进行基因分析。结果显示:检出7份JEV阳性样品,平均阳性率为10.14%,其中思茅区和宁洱县蚊阳性率最高,均为25.00%;扩增的5条完整JEV E基因序列与2009年分离的JEV老挝株亲缘关系最近,同源性为97.3%~98.7%,均属于基因I型;5条E基因序列(YN2016-1/2/3/4/5)在1 323位核苷酸位点首次出现C碱基替换,且YN2016-1在第340位氨基酸位点首次出现丙氨酸替换。结果表明:云南省南部地区蚊JEV的携带率较高,尤其是思茅区和宁洱县;蚊携带的JEV出现了核苷酸和氨基酸变异,应注意对其加强监测。

In order to investigate the prevalence and variation situation of Japanese encephalitis virus（JEV）in mosquitoes in the southern area of Yunnan Province,6 952 mosquitoes were collected from 4 counties during August to October of 2016 and merged into 69 samples. JEV of 69 samples was detected by RT-PCR method,and its gene mutations were analyzed. The results showed that 7 samples were detected JEV-positive,with an average positive rate of 10.14%. The positive rates in Simao District and Ninger County were the highest and same,both of them were 25.00%. Five complete JEV E gene were amplified,of which the sequences were closely related to the JEV strain isolated from Laos in 2009,with the nucleotide homology of 97.3% to 98.7%,the five genes all belonged to the genotype I JEV. C base substitution occurred firstly at the 1 323 nucleotide sites of the five E genes （YN2016-1/2/3/4/5）,and alanine substitution at amino acid position 340 also firstly occurred in YN2016-1 strain. As a result,the carrying rate of JEV in mosquitoes in southern area of Yunnan Province was relatively high,especially in Simao and Ninger,and nucleotide and amino acid mutations appeared,hence,JEV surveillance should be strengthened.