云南库蠓中版纳病毒的首次分离及鉴定

First isolation and identification of Banna virus from Culicoides pools in Yunnan

目的了解云南库蠓携带病毒及感染情况。方法2011年9月．11月在云南曲靖市采集库蠓、牛血清及猪血清标本；库蠓上清液接种于C6／36细胞进行病毒分离；对可疑分离物进行分子生物学鉴定；采用微量中和试验检测牛、猪血清病毒抗体。结果捕获到的18160只库蠓中，短跗库蠓8300只（45．7％），琉球库蠓7100只（39．1％）。分离到2株阳性分离物，命名为SC093和SC233。经鉴定，其VP2、VP4、VP8序列与版纳病毒中国株（AF134526）核苷酸序列同源性为99．0％，属于版纳病毒；1份牛血清与SC093和SC233病毒株中和抗体滴度分别为160和40，阳性率为0．5％（1／200）；10份猪血清与SC093和SC233病毒中和滴度分别为80—320和20—80，阳性率为1．7％（10／535）。结论所分离的SC093和SC233病毒株经鉴定为版纳病毒，并能引起猪和牛的感染，这是首次从库蠓中分离到版纳病毒。

Objective To understand the virus-carrying status and infection condition of Culicoides in Yunnan province. Methods Culicoides, cattle serum samples and pig serum samples were collected in Qujing City in Yunnan province from Sep. to Nov. in 2011 ; the supernatant of Culicoides was inoculated in C6/36 cells to isolate virus. Suspected isolates were identified by molecular biology techniques and titers of virus antibodies in pigs and cattles serum samples were tested by VN. Results 8 300 short tarsal Culicoides （8 300/18 160） and 7 100 Ryukyu Culicoides （7 100/18 160） were identified among 18 160 Culieoides specimens. Two suspected virus strains were isolated and designated as SC093 and SC233. The nucleofide sequence homology of VP2, VP4 and VP8 sequences with Banna virus Chinese strain （Accession number： AF134526） is up to 99%. 1 out of 200（1/200） cattle serum samples was antibody positive against Banna virus with 0. 5% positive rate. And the neutralizing antibody titers of SC093 and SC233 with above Barma virus antibody positive cattle serum were 160 and 40. 10 out of 535 （ 10/535 ） pig serum samples were antibody positive against Banna virus with 1.7% positive rate. And the neutralizing antibody titers of SC093 and SC233 with above Banna virus antibody positive pig serum samples were 80-320 and 20-80 respectively. Conclusions The SC093 and SC233 virus strains isolated from Shizong were identified to be Banna virus and it could cause infection in pigs and cattles. This is the first report that Banna virus was isolated from Culicoides.