新疆石河子地区牛病毒性腹泻病毒的分子流行病学调查

Epidemiology Investigation of Bovine Viral Diarrhea Virus in Shihezi,Xinjiang

根据GenBank中公布的牛病毒性腹泻病毒(BVDV)5'UTR保守区基因序列,设计3对引物,应用逆转录一聚合酶链反应(RT-PCR)检测方法对采自石河子地区3个场的64份牛全血样品进行核酸检测及测序。结果表明:BVDV阳性率为39.06%(25/64),其中有22对母子对应样品,母牛阳性率为40.91%,犊牛为45.45%,提示新疆石河子地区BVDV垂直感染较严重。9头牛表现临床症状,阳性率为22%,其余为临床健康牛,阳性率为41.81%,数据显示新疆石河子地区奶牛BVDV隐性感染严重。测序得到2条不同的序列,经5'UTR区域核酸序列同源性比较和系统发生分析表明2株病毒与VEDEVAC(匈牙利弱毒疫苗株)亲缘关系最近,同源性达96.2%～100%,用DNASTAR软件进行基因与系统发生进化关系分析属于BVDV-1b基因亚型,未检测到BVDV-2型病毒。提示新疆石河子地区BVDV流行株为BVDV-1b亚型,且经生物型鉴定,所测阳性样品为非致细胞病变型。本研究可为今后的流行病学研究和疫苗应用等防制措施提供依据。

According to 5 ＇UTR sequence of different genotypes and subgroups of BVDV strains, pairs of primer were designed. 64 whole blood samples which were collected from 3 cattle farms in Shihezi were detected by nested RT-PCR assay and sequencing. 39. 06% （25/64） samples were positive for BVDV with RT-PCR. 22 matched-pairs specimens were detected. The Cow-positive rate was 40.91% and the calf was 45.45%. BVDV vertical infection was more serious in Shihezi region. Only 9 cattle showed clinical symptoms, the positive rate was 22%. The positive rate of the remaining normal cattle was 41.81%. Data shows the region of Xinjiang Shihezi cows were infected with BVDV seriously. Alignment of the 5＇UTR sequences of the Shihezi isolates showed 2 different sequences. In addition,Phylogenetic analysis revealed that all viruses were found in group BVDV-Ⅰb. No BVDV type Ⅱ virus was discovered. These results suggest that the BVDV isolated reflect that the virus predominant genotype is BVDV- Ⅰ b in Shihezi. And by the biological-type identification, the isolates were non-cytopathic type. Information obtained from this study would also be useful when carrying out epidemiological surveys of domestic BVDV and vaccine application in Chinese cattle population.