黄羽父母代种鸡混合感染禽白血病病毒与马立克病病毒的鉴定

Identification of co-infection with avian leukosis virus(ALV) and Marek's disease virus(MDV) in the Yellow chicken parent stock

广西某养殖场130日龄父母代种鸡发生临床肿瘤样病变和死亡,对病鸡采用病理解剖、组织病理学观察、PCR检测、病毒分离以及分离株重要基因的序列测定和病原鉴定。结果显示:病鸡的心脏、肝脏、脾脏等部位表现有肿瘤样病变; PCR检测及病毒分离培养有J亚群禽白血病病毒(avian leukosis virus subgroup J,ALV-J)和马立克病病毒(Marek's disease virus,MDV)的感染; ALV-J分离株env基因的序列与10株ALV-J参考株的核苷酸相似性为87. 2%～97. 7%,与ALV A-E亚型参考株的相似性为53. 5%～54. 7%;与ALV-J英国原型株HPRS-103的env基因糖基化位点进行分析比较,部分糖基化位点发生了改变; MDV分离株meq基因序列与8株MDV参考株的核苷酸相似性为98. 7%～99. 4%,分离株在第71～80位氨基酸发生突变,符合国内强毒分离株的特征。结果说明:该鸡群为ALV-J和MDV的混合感染。

A parent stock of breeding chickens on a farm in Guangxipresented clinical tumor-like lesions and suffered from death at 130 days of age. Pathological anatomy,histopathological observation,PCR detection,virus isolation,and sequencing and analysis of important genes of isolates from the virus of the diseased chickens were performed for diagnosis. The results showed that the heart,liver,spleen and other organs of the diseased chickens showed tumor-like gross lesions. PCR detection and virus isolation of the cell cultures showed co-infection of avian leukosis virus subgroup J( ALV-J) and Marek’s disease virus( MDV). The nucleotide sequence of the env gene of the ALV-J isolate was 87. 2%-97. 7% similar to those of the 10 ALV-J reference strains and 53. 5%-54. 7% similar to those of the ALV A-E subtype reference strains. Comparison of the glycosylation sites with the British ALV-J prototype strain HPRS-103 revealed changes of some glycosylation sites. The meq gene nucleotide sequence of the MDV isolate was 98. 7%-99. 4% similar with 8 MDV reference strains and the mutations at the region of No. 71-80 amino acids were found,which was consistent with the characteristics of the domestic virulent MDV isolates( v MDV). The results obtained here indicated that the flock of the studied chickens was co-infected with ALV-J and MDV.