鸡传染性支气管炎病毒合肥分离株的致病性分析  

Pathogenicity analysis of one isolate of avian infectious bronchitis virus from Hefei

作　　者：蓝嘉宁 卞希一 盛豪 肖鹏 颜焰 周继勇[1,2] 廖敏[1,2] LAN Jianing;BIAN Xiyi;SHENG Hao;XIAO Peng;YAN Yan;ZHOU Jiyong;LIAO Min(College of Animal Sciences,Zhejiang University,Hangzhou 310058,China;Key Laboratory of Animal Virology of Ministry of Agriculture and Rural Affairs,Hangzhou 310058,China)

机构地区：[1]浙江大学动物科学学院,浙江杭州310058 [2]浙江大学农业农村部动物病毒学重点实验室,浙江杭州310058

出　　处：《中国兽医学报》2024年第9期1854-1864,共11页Chinese Journal of Veterinary Science

基　　金：国家重点研发计划资助项目(2021YFD1801102);浙江省基础公益计划资助项目(LGN22C18003)。

摘　　要：旨在为分离鉴定鸡传染性支气管炎病毒(infectious bronchitis virus,IBV)并研究其致病性。从疑似传染性支气管炎(infectious bronchitis,IB)感染的安徽合肥临床送检样品中成功分离到1株IBV(HF210416)。该毒株S1基因测序分析表明HF210416属于GI-22基因型,与参考的GI-22型毒株S1基因序列存在较大差异,同源性仅在84.5%~87.8%之间。重组分析结果显示,HF210416为重组毒株,主要亲本为YX10(GI-19型),次要亲本为YN(GI-19型)。2日龄SPF雏鸡感染HF210416分离株表现明显的呼吸困难、精神沉郁、排水样粪便等临床症状;感染鸡发病较急,接种后2 d便出现死亡现象,死亡持续至第5天,病死率为33.33%(5/15);攻毒后14 d,雏鸡恢复健康;攻毒鸡咽肛拭子的RT-PCR检测结果显示,14 d的试验期内能持续检测到攻毒鸡的排毒;剖检死亡和未死亡的感染鸡发现肾脏肿大、苍白,并伴有明显的尿酸盐沉积等病变;组织病理切片HE染色显示气管纤毛脱落,免疫组化结果显示气管、肺脏、肾脏均观察到明显的病毒信号。病毒载量测定结果表明,HF210416在肾脏组织中的载量最高,其次在盲肠扁桃体和气管中也具有较强的复制能力;血清中和试验结果表明,HF210416对GI-22同基因型毒株具有较好的中和效果,但对其他基因型毒株中和效果较差,不适合作为疫苗的候选毒株。总而言之,GI-22型分离株HF210416对雏鸡具有较强的致病性和嗜肾性,其基因组遗传特性与免疫原性与其他毒株均存在较大差异,该研究丰富了IBV毒种资源,为了解GI-22基因型病毒在中国的流行及其致病性提供了参考数据。To investigate the epidemiology of avian infectious bronchitis virus(IBV)and study the pathogenicity of IBV isolate,we isolated the IBV field strain from a clinical sample of chickens suspected to be infected with infectious bronchitis virus(IBV)from Hefei,Anhui Province,named HF210416.Sequencing analysis of the S1 gene showed that HF210416 belonged to the GI-22 genotype,which was significantly differed from that of the reference GI-22-type strains,with homology ranging only from 84.5%to 87.8%.Recombinant analysis showed that HF210416 was a recombinant strain,with YX10(GI-19)as the major parent and YN(GI-19)as the minor parent.2-day-old SPF chicks infected with the HF210416 isolate showed clinical symptoms such as breathing with difficulty,depression and excreting watery droppings;the infected chicks had a rapid onset of disease,with mortality occurring on the second day of inoculation,and mortality persisted until the fifth day,with 33.33%(5/15)mortality rate.The infected chicks recovered the 14th day after inoculation.RT-PCR detection of pharyngeal-anal swabs showed that the virus shedding by infected chicks could be continuously detected within 14 days of the test period;Enlarged and pale kidney as well as urate deposition in the kidney were observed in infected dead and undead chicks;and the HE staining of histopathological slices showed that the cilia of trachea were removed.Immunohistochemistry showed that obvious viral signals were observed in the trachea,lungs,and kidneys.The viral load of various tissues was detected by RT-qPCR and it showed that HF210416 had the highest replication efficiency in kidney tissues,then in cecum tonsils and trachea.The results of serum neutralization test showed that HF210416 had a better neutralization effect on GI-22 homologous strains,but poorer neutralization effect on other genotypes strains,suggesting that HF210416 is not suitable for vaccine candidate.In conclusion,the GI-22 isolate HF210416 is highly pathogenic and nephrotropic to chicks,and its genomic genetic chara

关 键 词：鸡传染性支气管炎病毒 安徽合肥分离株 GI-22型 致病性 

分 类 号：S852.65[农业科学—基础兽医学]