1株鸡传染性支气管炎病毒的分离鉴定及生物学特性研究

Isolation,Identification and Biological characteristic Study of an Avian Infectious Bronchitis Virus

为跟踪传染性支气管炎病流行情况,2015年我们从在江苏某养鸡场疑似传染性支气管炎发病鸡群采集分离到1株疑似传染性支气管炎病毒,对其进行了鉴定和生物学特性研究。结果在鸡胚上连传6代出现鸡胚典型病变,死亡鸡胚全身出血明显,未死鸡胚发育受阻,呈明显的侏儒胚、蜷缩。分离株S1基因RT-PCR扩增可见到清晰的1. 7 kb左右大小的条带,与引物设计的预期结果相符,与Gen Bank中的IBV序列进行比对和分析,从进化树看,分离株属于IBV当前主要流行的QX型。电镜下观察可见直径为80～120 nm,有囊膜和纤突的冠状病毒粒子;经卵磷脂酶C处理后能凝集鸡红细胞,并能特异性地被该分离株的高免血清所抑制;对热、酸碱、胰酶有一定耐受性,对脂溶剂敏感,符合鸡传染性支气管关病毒(IBV)有囊膜的特性;该分离株的最小致病量为102. 0EID50。该毒株灭活苗0. 25 m L/只免疫即可达到良好的免疫效果。以上结果表明,该分离株符合鸡传染性支气管炎病毒的特性。

In order to invesgate the epidemics of infectious brunchitis, we isolated an avian intectious bronchitis vinas from chickens, suspected of infectious bronchitis,in a chicken farm in Jiangsu province, 2015. We identified and characterized this virus. We obtained an avian infectious bronchitis virus through a continuous passageof six generations in embryos,which resulted in typical embryo lesions and martality. The embryo lesions included hemorrhage, stunting and curling of the embryo. The RT-PCR amplification of the S1 gene of the isolate showed a clear band of about 1.7 kb, which was in consistent with the expected target of the primer design. We compared the sequence with the IBV sequence in Genbank,and the phylogenetic tree analysis showed that the isolate belonged to the popular QX type. Biological characteristics showed that diameter of this virus particle was approximately 80- 120 nm, and the particle had capsules and dendritic coronavirus particles. The virus agglutinated chicken red blood cells ＂after treating with Iccithinase C, and virus-neutralizing test showed that its growth was inhibited by hyper-immune serum. The virus was resistant to heal, trypsin, acid and alkali, but sensitive to lipid solvent, which were consistent with the capsule characteristics. The minimum pathogenic dose was 102. OEIDS0. 0. 25 mL immunity dose of this isolate protected vaccinated chickens against challenge. The resuhs indicated that the strain was an avian infectious bronchitis virus