鸡腺病毒血清8a型毒株的分离鉴定及致病特点  

Isolation and Pathogenicity of Fowl Adenovirus Serotype 8a Strain

作　　者：李慧昕[1] 宋文平 韩宗玺[1] 刘胜旺[1] LI HuiXin;SONG WenPing;HAN ZongXi;LIU ShengWang(Harbin Veterinary Research Institute,Chinese Academy of Agricultural Sciences/State Key Laboratory for Animal Disease Control and Prevention,Harbin 150069)

机构地区：[1]中国农业科学院哈尔滨兽医研究所/动物疫病防控全国重点实验室,哈尔滨150069

出　　处：《中国农业科学》2023年第16期3226-3236,I0005-I0009,共16页Scientia Agricultura Sinica

基　　金：黑龙江省自然科学基金团队项目(TD2021C001)。

摘　　要：【目的】鸡腺病毒(fowl adenovirus,FAdV)在鸡群中流行广泛且血清型众多,不同血清型毒株对鸡的致病能力尚不完全清楚。通过对FAdV-8a型分离株的致病特点进行研究,为了解血清8a型毒株的致病能力、进而对鸡群中不同血清型FAdV的防控提供科学依据。【方法】2017年,从发病鸡群采集肝脏组织,组织匀浆后无菌处理,接种鸡胚分离病毒,经PCR鉴定,初步确定分离毒株为鸡腺病毒。为确定分离株的分类情况,对病毒的全基因组进行测序及序列分析,经基因组序列比对及hexon基因遗传演化分析,从分子水平确定病毒的种/血清型。为了解分离株的致病特点和致病能力,30只10日龄SPF鸡随机分成2组,经滴鼻和点眼途径人工感染。从临床发病(发病率和死亡率)、病毒血症、排毒、循环抗体消长规律及其与中和抗体相关性、感染后5 d鸡剖检症状及病理组织学检测、病毒的组织分布及组织嗜性等方面评价分离株JL/170408对10日龄SPF鸡的致病性。【结果】对分离株的全基因组序列进行测定和分析,表明基因组序列与FAdV-8a型参考毒株TR59株同源性最高,基因组结构和编码基因特点与该毒株高度一致。基于全基因组序列进行遗传演化分析,分离株处于FAdV-E种的进化分支内,与TR59株亲缘关系较近。同时对分型基因hexon基因进行遗传演化分析,分离株划分为8a血清型。综合分离株基因组特征及遗传演化分析,确定分离株JL/170408为FAdV-E种、血清8a型毒株。分离株感染10日龄SPF鸡,感染后3—13 d是临床发病高峰期,但不引起鸡只死亡。感染后3 d开始出现病毒血症并经呼吸道和消化道排毒,病毒血症持续时间长达51 d之久,此时感染鸡的抗体未全部转为阳性且循环抗体滴度较低(平均S/P<1),低水平的循环抗体不能有效清除病毒。感染后54 d,感染鸡抗体滴度出现高峰(平均S/P>2),有效清除感染鸡体内病毒,表现为病�【Objective】Fowl adenovirus(FAdV)circulates in chicken flocks with multiple serotypes,while there is less information about the pathogenicity of all serotype strains.To understand the capability of causing disease as a primary pathogen to chicken of the FAdV-8a strain,we carry out the experiment for evaluating the pathogenic characteristics of this serotype strain,which will help making the control strategy for breeding.【Method】In 2017,liver tissue was collected form the diseased flocks.The liver tissue homogenates were inoculated into the embryo egg for isolating the virus.The isolate was determined as a FAdV strain after PCR detection.To classify the isolate,genomic sequencing and the genetic evolution based on the complete genome sequence and the hexon gene sequence were performed.To clarify the pathogenicity,thirty 10-day-old SPF chicks were randomly divided into 2groups and exposed to the isolate JL/170408 via nasal inhalation and eye droppings.The clinical syndrome(including morbidity and mortality),viremia,virus shedding,circulating antibody,postmortem examination and histopathological detection at 5 days post infection(d.p.i.),viral distribution and the tropism on tissues were performed to evaluate the pathogenic capability and characteristics of JL/170408 to SPF chicks.【Result】The complete genome sequencing showed that there were the highest identity between the isolate and the FAdV-8a TR59 strain.They showed high identity in the genomic structure and the encoding gene.Phylogenetic analysis based on the complete genome sequence,the isolate JL/170408 was in the cluster of FAdV-E,further was grouped into the branch of serotype 8a based on the hexon gene.Consequently,the isolate JL/170408 was determined as FAdV-8a serotype within the species of FAdV-E.The clinical peak was observed from 3 to 13 d.p.i.without death.The virus shedding and viremia was detected as early as 3 d.p.i.and last for a long period at least 51d,the antibody was not positive conversion completely and the mean ELISA titer S/P<

关 键 词：鸡腺病毒 血清8a型 基因组特征 致病性 

分 类 号：S852.65[农业科学—基础兽医学]