云南省部分养殖场鸡传染性贫血病毒核酸检测及VP2基因序列分析

Detection of CAV Nucleic Acids in Some Farms in Yunnan Province and Analysis on Its VP2 Gene Sequence

为了解云南省鸡传染性贫血病毒(chicken anemia virus,CAV)的流行及其VP2基因变异情况,2017—2020年,在昆明市、楚雄州、大理州、红河州、玉溪市等家禽养殖密集区的89个鸡场,采集422份疑似病鸡肝脏样品,通过PCR方法检测CAV核酸。结果显示,检出阳性245份,平均阳性率为58.06%;不同年份的CAV核酸阳性率为53.61%~60.91%,不同区域核酸阳性率为51.68%~63.52%。对3份CAV阳性样品进行VP2基因序列分析,发现核苷酸序列同源性为99.6%~99.8%,与参考毒株1852TW和N7的核苷酸同源性为99.6%~99.8%,均属于GroupA分支。结果表明:云南省普遍存在CAV感染,且感染较严重;VP2基因仍可作为PCR病毒核酸检测的首选目标基因。通过加强鸡群CAV监测,淘汰阳性鸡群和结合疫苗免疫,可减少该病造成的损失。

In order to identify the prevalence of chicken anemia virus(CAV)and its VP2 gene variation in Yunnan Province from 2017 to 2020,422 liver samples of suspected chickens were collected from 89 farms in intensive poultry farming regions including Kunming,Chuxiong,Dali,Honghe and Yuxi cities to detect CAV nucleic acids by PCR.The results showed that 245 samples were positive,with an average positive rate of 58.06%;the positive rates of CAV nucleic acids were 53.61%to 60.91%in different years and 51.68%to 63.52%in various regions.It was found that,by analysis on VP2 gene sequence of three positive samples,their nucleotide sequence homologies ranged 99.6%to99.8%,and nucleotide homologies with reference strains 1852 TW and N7 were 99.6%to 99.8%,all of which belonged to Group A branch.In conclusion,CAV was widely and seriously prevalent in Yunnan,and VP2 gene could still be used as a preferred target gene for detecting virus nucleic acids by PCR.Any loss caused by the disease could be reduced through intensifying monitoring of CAV in chickens,eliminating positive chickens and strengthening vaccination.