鸡传染性支气管炎病毒的分离鉴定及其致病性的研究

Isolation, identification and pathogenicity of a novel infectious bronchitis virus in chickens

本研究从江苏省某鸡场疑似鸡传染性支气管炎(IB)的病料中,利用SPF鸡胚尿囊腔接种的方法分离出1株传染性支气管炎病毒(IBV),命名为CK/CH/JS/TZHY48。经RT-PCR检测,该株IBV的S1基因全长1638bp。遗传进化分析显示,分离株属于基因Ⅵ型,与常规疫苗株H120和H52的同源性较远。分离株对鸡胚有明显的致矮小化作用;对新城疫病毒有显著的干扰作用。动物回归试验结果显示,该分离株对7日龄SPF鸡的发病率为100%,致死率为40%,发病鸡出现气管啰音,甩头流鼻涕等呼吸道症状;病死鸡的剖检病理变化主要表现为肾苍白肿大,花斑肾,有大量明显的白色尿酸盐沉积,气管环出血。本研究可为IBV的遗传进化、致病机制以及免疫防控提供参考。

In this study,an avian infectious bronchitis virus designated as CK/CH/JS/TZHY48 was isolated and identified from a commercial chickens farm in Jiangsu Province through being inoculated into SPF eggs via the allantoic cavity.The length of S1 gene of the isolate was 1 638 bp by RT-PCR.Based upon data arising from S1 sequence and phylogenetic analyses,the IBV isolate was classified into Gene typeⅥ,which was genetically different from vaccine isolates H120和H52.The pathogenicity of CK/CH/JS/TZHY48 strain in 7-day-old SPF chickens was characterized.The morbidity of challenged chickens was 100%and the mortality was 40%.The infected chickens had tracheal rales,head-twitch,snoring etc.of respiratory symptoms.Furthermore,the typical nephhropothhogenic lesions,oedema with some necrotic foci and obvious urate aggradation observed in kidneys and tracheal ring bleeding occurred in those infected dead chickens.The above-mentioned results can provide references for the genetic evolution,pathogenesis and immune control of IBV.