台湾基因Ⅰ型鸡传染性支气管炎病毒SCTW株的分离鉴定及致病性研究

摘要

为分离鉴定鸡传染性支气管炎病毒(IBV)及其致病性,本研究通过病料鸡胚接种和鸡胚尿囊液的RT-PCR检测,从四川某养鸡场的发病鸡群中分离出一株IBV.其S1基因测序分析表明,该病毒分离株属于台湾基因Ⅰ型(TWⅠ)IBV,命名为SCTW株,这是中国大陆地区首次分离的TWⅠ型IBV.将该分离株与禽源致病性大肠杆菌(E.coli)分别或混合感染15日龄白羽肉鸡以鉴定其致病性,结果显示:SCTW分离株具有较强的致病性;而且E.coli的混合感染可明显增加SCTW的发病率和病死率,使其组织病理变化更加严重.因此,加强IBV的流行病学调查,做好E.coli的防治,对鸡传染性支气管炎(IB)的防制有重要的意义.%An avian infectious bronchitis virus (IBV) was isolated from affected chickens in a farm of Sichuan area by inoculation of chick embryo and RT-PCR detection of the allantoic fluid.The sequence analysis of S1 gene showed that the isolate belongs to Taiwan genotype Ⅰ (TW Ⅰ) of IBV,designated SCTW,which was first isolated in mainland of China.Then 15 day-old white feather broilers were infected with the SCTW isolate or E.coli originated from avian or both of them.The results demonstrated that SCTW had high pathogenicity to checks with a 100％ morbidity and 40％ mortality in co-infected group with SCTW and E.coli,comparing with the 80％ morbidity and 10％ mortality in only SCTW infected group.Furthermore,the tissue lesions were more severe in co-infected group than that in SCTW or E.coli infected group.Hence,the prevention and control of IB not only need to the epidemic investigation of IBV,but also need to control E.coli primarily.