牛环曲病毒云南流行株N基因序列分析

Detection of bovine torovirus in some areas of Yunnan Province and analysis of its N gene sequence

为深入了解云南省牛环曲病毒(bovine torovirus,BToV)的流行现状及遗传进化趋势,2021年3月—2023年6月采集云南省9市15个养牛场不同年龄段的655份牛粪便样品,进行BToV RT-PCR检测,并对其中具有代表性的6份样品进行N基因测序分析。结果显示:BToV阳性检出率为10.84%(71/655);扩增得到6条完整的N基因序列,其同源性在98.4%~100%,与国内外参考毒株相比发现,6个毒株N基因与我国四川、黑龙江毒株同源性高,亲缘关系较近,可能是由引种、调运或动物产品交易传播而来;发现2个毒株发生氨基酸突变,可能是由于云南独特的气候和不同的饲养条件造成的。结果表明:牛环曲病毒在云南存在范围较广,须密切注意监测、加强检疫,同时加快疫苗研发。

In order to gain a deeper understanding of the prevalence and genetic evolution trends of bovine circovirus(BToV)in Yunnan Province,655 cow feces samples from 15 cattle farms in 9 cities of Yunnan Province were collected from March 2021 to February 2023 and BToV RT-PCR detection was performed.Six representative samples were analyzed for N gene sequencing.The results showed that the positive detection rate of BToV was 10.84%(71/655);Six complete N gene sequences were amplified,with homology ranging from 98.4%to 100%.Compared with domestic and foreign reference strains,it was found that the N genes of the six strains had high homology and close genetic relationships with domestic Sichuan and Heilongjiang strains,possibly originating from their transmission;two strains of the virus were found to have amino acid mutations,possibly due to the unique climate and different feeding conditions in Yunnan.The results indicate that bovine circovirus has been widely spread in Yunnan,possibly through introduction,transportation,or animal product trading.So,it is necessary to strengthen quarantine,pay attention to monitoring,and accelerate vaccine development.