目的在山东省南水北调沿线选择微山韩庄、任城太白湖和泰安东平湖3个地区,调查蚊类密度消长及流行性乙型脑炎(乙脑)病毒自然感染状况,为当地蚊虫控制与乙脑防治工作提供科学依据。方法 2015年6-9月,采用人帐法在上述3个地区采集蚊虫标本,分类计数;将蚊虫标本研磨后提取核酸,采用实时荧光定量PCR法检测乙脑病毒核酸。结果 2015年6-9月在3个监测点共捕获蚊虫6属17种16 711只,以三带喙库蚊(39.55%)和淡色库蚊(38.69%)为优势蚊种;蚊虫密度随季节消长均以8月最高。采用实时荧光定量PCR法,在三带喙库蚊、淡色库蚊、黄色轲蚊中检测到乙脑病毒核酸,批阳性率分别为22.96%、7.58%和16.67%。结论山东省南水北调沿线蚊虫密度依然较高,且多个蚊种中检测到乙脑病毒核酸,提示该地区存在乙脑病毒感染风险。 Objective To investigate the natural infection of epidemic encephalitis B (JEV) in mosquito population in Hanzhuang, Weishan Taibaihu and Dongping Lake in Tai’an along the route of South-North Water Diversion Project in Shandong Province. JE prevention and control work to provide a scientific basis. Methods From June to September 2015, samples of mosquitoes were collected in the above-mentioned three regions by using the method of human account, and the samples were counted. The mosquitoes were ground and extracted, and the nucleic acids of JE virus were detected by real-time fluorescence quantitative PCR. Results A total of 16 711 mosquitoes belonging to 6 genera and 17 species were collected from June to September 2015 at three monitoring sites. Culex tritaeniorhynchus (39.55%) and Culex pipiens pallens (38.69%) were dominant mosquito species. The mosquito density varied with seasons Growth and decline are the highest in August. The real-time fluorescent quantitative PCR method was used to detect JE virus nucleic acid in Culex tritaeniorhynchus, Culex pipiens pallens and Keel mosellae. The positive rates of JEV were 22.96%, 7.58% and 16.67% respectively. Conclusion The density of mosquitoes in Shandong Province along the South-to-North Water Diversion Project is still high, and JE virus nucleic acids are detected in several mosquito species, suggesting that there is a risk of JE virus infection in this area.