鸡传染性支气管炎病毒CQ/01/2004株的分离与鉴定

Isolation and identification of an infectious bronchitis virus strain CQ/01/2004

2004年从重庆某肉用鸡场疑似鸡传染性支气管炎的病鸡中采集病料,按常规处理后接种9～10日龄鸡胚,通过鸡胚连续传代培养3代,并对该分离毒株的鸡胚致病性、血凝性和NDV的干扰特性进行检测,同时进行了动物回归试验。结果表明,该分离株具有IBV感染特征,可使鸡胚胚体出血、蜷缩、矮化;该分离毒株无直接血凝性,对NDV有明显的干扰作用;动物回归试验中有75%的感染鸡在10d内发病或死亡。剖检病死鸡可见肾苍白、肿胀,肾小管内充塞大量尿酸盐,支气管有出血点、有大量粘液。采用反转录-聚合酶链式反应(RT-PCR)技术对CQ/01/2004的纤突蛋白S1基因进行扩增、克隆和序列测定,结果表明该基因具有IBVS1基因的共有分子特征,将测序结果提交GenBank进行同源性检索,发现分离株CQ/01/2004和J株S1的同源性最高,核苷酸同源性为94%,氨基酸同源性为89.4%,与M41的核苷酸同源性为80.6%,氨基酸同源性为78.0%。试验结果表明,分离的病毒株CQ/01/2004为鸡传染性支气管炎病毒。

A field strain of infectious bronchitis virus （IBV） named CQ/01/2004 was isolated from the affected broilers in Chongqing. Biological characteristics of the isolate were studied by virus pathogenicity to SPF chicken embryos and chickens, hemagglutination activity of virus to chicken red blood cells, interference with NDV. The data indicated that the isolate didn＇t hemagglutinate chicken red blood cells directly but interfere NDV propagation in chick embryos. The gross lesions caused by the isolate to SPF chicken embryos and SPF chickens were visible. In addition, S1 gene of CQ/01/2004 was amplified by RT-PCR and the sequence has been submitted to GenBank （the accession number is AY769993）. Sequence analysis showed that the nucleotide sequence was homogenous （with homology rate of 94 %） with S1 gene of strain J and （with homology rate of 80.6 %） of strain M41. Furthermore the phylogenetic trees analysis revealed that the isolates CQ/01/2004 was an IBV strain .