浙江省蚊媒携带流行性乙型脑炎病毒的分布特点

目的 了解浙江部分地区蚊媒及猪携带流行性乙型脑炎(乙脑)病毒情况以及浙江省存在的乙脑病毒基因型别.方法 于2007年5月至10月在浙江省仙居、龙泉和慈溪3个县人房及猪舍采集蚊虫标本和猪血清,共采集10 662只蚊虫和204份猪血清,蚊虫标本中以淡色库蚊和中华按蚊为主.利用病毒分离和荧光定量逆转录聚合酶链反应(RT-PCR)方法检测蚊虫携带乙脑病毒,应用酶联接免疫吸附剂测定(ELISA)方法对猪血清进行抗体检测.应用荧光定量RT-PCR方法对细胞分离株进行病毒鉴定;利用RT-PCR方法扩增新分离乙脑病毒PrM基因,并对细胞分离到的病毒进行基因分型.结果 在蚊虫标本中检出7批乙脑病毒核酸阳性样本,并分离出3株病毒,经鉴定3株病毒均为乙脑病毒,基因分析表明3株病毒均属于基因Ⅰ型乙脑病毒.猪血清有121份阳性,总阳性率为59.3%.6月份有50%以上的猪血清中乙脑病毒抗体呈阳性.结论 浙江省部分地区存在着乙脑的传播媒介,在蚊媒和猪中携带有乙脑病毒;采集的蚊虫标本中分离到3株病毒,经鉴定为基因Ⅰ型乙脑病毒,是近年来在浙江省首次分离到的基因Ⅰ型乙脑病毒.

The distributions of mosquito vectors carrying Japanese encephalitis virus in Zhejiang province

Objective To investigate the natural infection and genotype of Japanese encephalitis virus in mosquitoes and swine in some areas of Zhejiang province. Methods Samples of mosquitoes and sera of swine were collected in three counties (Xianju, Longquan and Cixi)of Zhejiang province from May to October in 2007.10 662 mosquitoes were collected during 2007, of which, C. pipiens pallens and C. quinquefasciatus were the most dominant species and 204 pig serum samples were detected. Japanese encephalitis virus in mosquitoes were detected by virus isolation and real time RT-PCR. The antibody against Japanese encephalitis virus in swine was detected by ELISA. The isolated strain were identified by real time RT-PCR. The PrM gene of the isolated strain was amplified by RT-PCR. Three strains were typed by the gene of PrM. Results Seven positive mosquitoe samples were identified by real time RT-PCR. Three strains were isolated and identified by real time RT-PCR. The PrM gene was cloned and sequenced. The phylogenetic analysis showed that three isolates belong to genotype Ⅰ of Japanese encephalitis virus. Of 204 swine serum samples, 121 positive samples were identified positives. Above 50% sera samples from swine were positive in June. Conclusion The vector of Japanese encephalitis virus existed and carried the Japanese encephalitis virus in these areas of Zhejiang province. Three strains of Japanese encephalitis virus were isolated from mosquito pools collected in Zhejiang province. It should be the first isolation of genotype Ⅰ Japanese encephalitis virus in Zhejiang province in recent years.