鸡传染性喉气管炎病毒WF03株关键抗原基因和毒力基因的遗传演化与致病性分析  

Phylogenetic Analysis and Pathogenicity of an Avian Infectious Laryngotracheitis Virus Strain WF03

作　　者：张翼 王晨燕[1] 杨骁 邵国青 侯博[1] ZHANG Yi;WANG Chenyan;YANG Xiao;SHAO Guoqing;HOU Bo(Fujian Animal Disease Control Technology Development Center,Institute of Animal Husbandry and Veterinary Medicine,Fujian Academy of Agricultural Sciences,Fuzhou,Fujian 350013,China;MSD(Ningbo)Animal Health Technology Co.,Ltd.,Ningbo Zhejiang 315336,China;Institute of Veterinary Medicine,Jiangsu Academy of Agricultural Sciences,Nanjing,Jiangsu 210014,China)

机构地区：[1]福建省农业科学院畜牧兽医研究所/福建省畜禽疫病疾病防治工程技术研究中心,福州350013 [2]默沙东(宁波)动物保健科技有限公司,宁波315336 [3]江苏省农业科学院兽医研究所,南京210014

出　　处：《畜牧兽医学报》2023年第8期3435-3444,共10页ACTA VETERINARIA ET ZOOTECHNICA SINICA

基　　金：福建省农业科学院科技创新团队(CXTD2021014-3);福建省“5511”协同创新工程(XTCXGC2021008)。

摘　　要：本研究旨在分析近年分离自鸡传染性喉气管炎病毒(ILTV)活疫苗免疫失败鸡群的ILTV WF03株的部分关键抗原基因及毒力基因的变异情况和对鸡的致病力,为ILTV活疫苗的有效性评价提供一个稳定、可靠的攻毒毒株。通过ILTV临床分离株WF03的部分免疫原性基因和毒力相关基因进行克隆和测序,并与疫苗株和早期分离株进行遗传进化分析,同时在28和56日龄SPF鸡测定了该毒株的致病力。遗传进化分析结果表明:WF03株主要免疫原性基因和毒力相关基因与我国早期的分离株和现在部分商品化的疫苗株处在同一个大的进化分支,亲缘关系较近。致病力试验显示WF03株以10^(4.5)、10^(4).0、10^(3.5)和10^(3.0)EID_(50)·羽^(-1)的剂量感染28日龄SPF鸡后发病率分别为100%、100%、95%和85%,死亡率分别为45%、30%、35%和10%;以10^(4).0 EID_(50)·羽^(-1)的剂量感染56日龄SPF鸡的发病率和死亡率分别为100%和27.3%;所有发病鸡临床症状主要表现为咳血、呼吸困难、张口呼吸等典型的喉气管炎发病症状。结果表明:ILTV临床分离株WF03主要抗原基因和毒力基因与我国早期分离株和疫苗株相比未发生明显变异,属于强致病力毒株,其对SPF鸡的发病能力稳定,在10^(4.5)、10^(4).0、10^(3.5)和10^(3.0)EID_(50)·羽^(-1)攻毒剂量时均可以使80%以上的鸡发病。结果提示目前我国鸡群中存在着强致病力ILTV毒株流行,且WF03株可以作为疫苗效力评价的攻毒毒株,这将丰富我国当前ILTV毒株的流行病学数据库。This experiment analyzed the variations of key antigen genes and virulence genes of infectious laryngotracheitis virus(ILTV)WF03 strain isolated from chickens that failed to be immunized with live vaccine.And also,the virulence of WF 03 was tested in SPF chickens.The phylogenetic tree of key immunogenic genes and virulence related genes of clinical ILTV isolate WF03 was performed,and the pathogenicity of this strain infected 28 and 56 days-old SPF chickens was tested.The results showed that the key immunogenic genes and virulence related genes of the WF03 strain were in the similarity evolutionary branch with the early isolates from China and some commercialized vaccine strains.The pathogenicity experiment showed that when the 28 days-old SPF chicken were challenged with WF03 strain with the doses of 10^(4.5),10^(4).0,10^(3.5)and 10^(3.0)EID_(50),respectively,the morbidity was 100%,100%,95%and 85%,respectively,and the mortality was 45%,30%,35%and 10%,respectively.The morbidity and mortality to 56 days-old SPF chickens challenged with 10^(4).0 EID_(50)dose were 100%and 27.3%,respectively.The main clinical symptoms were hemoptysis,dyspnea,mouth breathing with same as typical symptoms of laryngotracheitis.The results showed that the clinical strain WF03 of ILTV was a high virulent strain and can be used as a challenge strain for vaccine efficacy,and its genetic characteristics were not significantly different from those of early isolates and vaccine strains in China.The results suggested that high virulent strains were prevalent in Chinese flocks,which will enrich the epidemiological database of current ILTV strains in China.

关 键 词：传染性喉气管炎病毒 遗传特征 致病力 

分 类 号：S852.659.1[农业科学—基础兽医学]