云南省景洪市2015年蚊虫感染病毒状况调查

Identification of Japanese encephalitis viral infections in mosquitoes in Jinghong city,Yunnan province,China

目的调查云南省西双版纳傣族自治州(西双版纳州)景洪市蚊虫自然感染登革热病毒(DENV)和流行性乙型脑炎(乙脑)病毒(JEV)状况,为相关疾病防控提供科学依据。方法 2015年8-9月在景洪市城区采集蚊虫标本,利用RT-PCR法检测DENV和JEV核酸,阳性标本进行C/Pr M基因序列测定以及同源性和系统进化分析。结果共捕获蚊虫4种2 009只,其中白纹伊蚊、埃及伊蚊、库蚊(未鉴定种类)和刺扰伊蚊分别为896、477、634和2只;从一批库蚊和一批白纹伊蚊中均检测到JEV核酸,并获得这2株JEV的C/Pr M基因核酸序列;进化分析结果表明,2株JEV与基因Ⅰ型JEV同处于一个进化分支,并与2009年红河哈尼族彝族自治州、2010年德宏傣族景颇族自治州和2008年甘肃省流行株亲缘关系较近。DENV检测结果均为阴性。结论 2015年景洪市存在基因Ⅰ型JEV流行,为西双版纳州首次从蚊虫中检出。今后仍需加强该地区乙脑病例及其媒介蚊虫的监测和防控,防止乙脑大范围流行。

Objective To investigate the natural infection with Dengue virus（DENV）and Japanese encephalitis virus（JEV）in mosquitoes in Jinghong city,Xishuangbanna prefecture,Yunnan province,China,and provide the scientific basis for its prevention and control.Methods Mosquito samples were collected from urban area of Jinghong in August and September 2015.Mosquito samples were tested for the nucleic acid of DENV and JEV by RT-PCR assay,and positive specimens were sequenced for C/Pr M gene for homology and phylogenetic analyses.Results A total of 2 009 mosquitoes were collected in urban area of Jinghong.Aedes albopictus,Ae.aegypti,Culex（species not identified）and Ae.vexans were 896,477,634,and 2 of the total,respectively.The JEV RNA were detected from one pool of Culex mosquitoes and one pool of Ae.albopictus mosquitoes.The sequences of C/Pr M genes of the 2 JEV strains were obtained.Homology and phylogenetic analyses showed that the 2 JEV strains are consistent with the genotypeⅠ（G-Ⅰ）and its clade of the same G-Ⅰ strains of JEV from Gen Bank,and the JEV strains from Jinghong were closely related to the JEV G-Ⅰ strains from Honghe prefecture of Yunnan in 2009,Dehong prefecture of Yunnan in 2010 and Gansu province,China in 2008.Mosquito samples tested negative for DENV in the study.Conclusion Existence of JEV G-Ⅰin Jinghong city of Xishuangbanna prefecture was firstly confirmed from mosquitoes in 2015.It should be strengthened to monitor and control Japanese encephalitis epidemics in this area.