鸡腺胃分离的传染性支气管炎病毒基因型与致病性研究

Genotype and pathogenicity of infectious bronchitis viruses isolated from proventriculitis cases

为明确传染性支气管炎病毒(IBV)是否是导致鸡腺胃炎的主要原因,对分离自腺胃炎病例的2个IBV毒株(CK/CH/HeB/2011/1和CK/CH/HeB/2011/2)的致病性进行研究。首先用SPF鸡胚对2株病毒进行扩增,收获的含毒鸡胚尿囊液经检测未发现其他外源病毒污染。经S1基因序列比对和遗传进化分析,2个毒株分别属于Mass和QX基因型。在致病性试验中,2株病毒按照106 EID50.mL-1的剂量分别滴鼻感染10只14日龄SPF鸡,攻毒后连续观察10d。2组试验鸡在攻毒后均出现典型的呼吸道症状,发病率为100%,致死率均为10%,剖检病理变化主要表现为间质性肾炎,但未观察到临床病例的腺胃炎病变。结果表明:分离自腺胃炎病例的IBV毒株存在多个基因型,这些毒株单独感染不一定诱发腺胃炎病变。

To study whether the infectious bronchitis virus （IBV） is the main causative agent of chicken proventriculitis, two IBV strains isolated from proventriculitis eases previously, CK/CH/HeB/2011/1 and CK/CH/HeB/2011/2, were chosed. Firstly, two IBVs were propagated in SPF embryonated ehicken eggs, and proved to be far away from any foreign virus pollution. The S1 genes were cloned by RT-PCR, and the sequencing results showed that S1 gene length was 1 611 and 1 620 bp respectively. Two IBVs were further grouped into different genotypes, Mass and QX, through sequence alignment and phylogenetic analysis. To determine the pathogenicity of these two IBVs, two groups of 10 14-day-old SPF chickens were infected with diluted virus （106 EIDs0. mL-1 ） through intranasal route. All chickens in both groups showed respiratory symptoms. Till 10 d postchallenge, the mortality was 90% for both groups. The consist- ent pathological change in all chickens was characterized as interstitial nephritis, and no proventrieulitis similar to clinical eases could be observed in any challenged chicken. The results suggested that multiple genotypes of IBV could be isolated from proventriculitis cases, and the studied two IBVs could not induce proventriculitis alone.