进口白羽肉种鸡禽白血病疫情鉴定

Diagnosis of avian leukosis in imported broiler breeders

2018年以来,某进口品种肉种鸡发生疑似禽白血病病例,流行范围广,危害严重,为确定该次疫情的病原,本研究从辽宁、山东等地发病鸡场采集55份疑似禽白血病病料样品。病理组织切片观察显示,病料样品肝脏和脾脏均有髓细胞样肿瘤细胞增生。针对禽白血病病毒(ALV)、鸡马立克氏病病毒(MDV)和网状内皮组织增生症病毒(REV)的特异性PCR检测结果显示,55份病料样品中ALV阳性样品12份(21.8%),MDV阳性样品1份(1.82%),REV均为阴性。将12份ALV阳性病料样品经处理后接种DF-1细胞进行病毒分离,ELISA检测结果显示有8份ALV群特异性抗原阳性。ALV多重PCR检测结果表明,8个分离株均为J亚群ALV(ALV-J),测序结果显示,8个分离株之间核苷酸序列同源性为99.5%~100%,与A、B、C、D、E亚群ALV的同源性仅为56.5%~58.8%,与ALV-J的同源性为90.7%~96.6%,进一步表明所有分离株均为ALV-J。上述结果表明,引起该次进口白羽父母代肉种鸡发生禽白血病的病原主要以ALV-J为主,该研究结果为疫情的溯源和有效防控奠定了基础。

Since 2018,imported broiler breeders emerged suspected cases of avian leukosis,which caused wide prevalence and seriously economic losses.To determine the pathogen of this case,55 suspected samples were collected from poultry farms in Liaoning and Shandong province.Myeloid tumor cell proliferation was observed by histopathological observation in the livers and spleens.Three tumor viruses:avian leukosis virus(ALV),Marek’s disease virus(MDV)and Reticuloendotheliosis virus(REV)were detected by special PCR and the result showed that among 55 samples,12 samples were positive ALV,1 sample was MDV positive and all of the samples were REV negative.All ALV positive samples were inoculated into DF-1 cells for viral isolation and 8 samples among them were ALV group specific antigen positive detected by ELISA.The ALV multiple PCR test results showed that 8 isolates belonged to subgroup J ALV(ALV-J).Sequence analysis indicated that the homology between the 8 isolates was 99.5%-100%,shared only 56.5%-58.8%homology with that of A,B,C,D,and E subgroup ALV,and 90.7%-96.6%with ALV-J,which further demonstrated that all 8 isolates belonged to ALV-J.All data indicate that ALV-J,as the primary pathogen,caused avian leukosis of imported broiler breeders.These results will contribute to track the source of this outbreak and provide a foundation for effective prevention and control measures for ALV.