两株H9N2亚型禽流感病毒的基因组序列分析及其对小鼠的致病性研究  

Analysis on genome sequence of two H9N2 avian influenza viruses and their pathogenicity in mice

作　　者：侯玉杰[1] 尹馨 房敬真 邓国华[1] 崔鹏飞[1] 王冬雪 施建忠[1] 陈化兰[1] HOU Yu-jie;YIN Xin;FANG Jing-zhen;DENG Guo-hua;CUI Peng-fei;WANG Dong-xue;SHI Jian-zhong;CHEN Hua-lan(Influenza Laboratory of the Ministry of Agricultural,State Key Laboratory of Veterinary Biotechnology,Harbin Veterinary Research Institute,Chinese Academy of Agricultural Sciences,Harbin 150069,China)

机构地区：[1]中国农业科学院哈尔滨兽医研究所兽医生物技术国家重点实验室/农业部动物流感重点实验室,黑龙江哈尔滨150069

出　　处：《中国预防兽医学报》2020年第11期1089-1094,共6页Chinese Journal of Preventive Veterinary Medicine

基　　金：国家重点研发项目(2016YFD0500201、2016YFD0500203);现代农业产业技术体系专项资金(CARS-41-G12);中央级公益性科研院所基本科研业务费专项(1610302017001)。

摘　　要：为了解H9N2亚型禽流感病毒(AIV)的生物学特性,本研究对2019年自青海省活禽市场家禽拭子和青海湖野鸟粪便中各分离到的一株H9N2亚型AIV,CK/QH/S1182/2019株和WB/QH/S1355/2019,并进行了病毒基因组序列测定、遗传演化分析和BALB/c小鼠致病性试验。HA序列分析显示,两株病毒的HA裂解位点均为333PSRSSR↓GLF341,不存在多个连续碱性氨基酸,符合低致病性禽流感病毒(LPAIV)分子特征。遗传演化分析结果显示,两株病毒的HA、NA基因均属欧亚分支。除WB/QH/S1355/2019株的M基因与A/chicken/Zhejiang/S1074/2016(H7N9)AIV株的M基因高度同源外,分离的两株病毒的其余基因节段均来源于H9N2亚型AIV。分离的两株H9N2 AIV的NA、PB1及NP基因亲缘关系较近,核苷酸同源性高达99%~100%,提示野鸟携带的H9N2亚型AIV与家禽来源的H9N2 AIV株可能存在基因重组的可能性。小鼠感染性试验结果显示,两株病毒均可在小鼠的鼻甲和肺中有效复制,但在小鼠的脑、脾脏和肾脏中均未检测到病毒,且在观察期内小鼠体质量均无明显变化,也未出现明显的临床症状,表明两株H9N2亚型AIV均对小鼠呈现低致病力。本研究对H9N2亚型AIV感染哺乳动物的风险评估提供了一定的数据支持,对该亚型AI的综合防控具有指导意义。Two H9N2 avian influenza viruses(AIVs)CK/QH/S1182/2019(H9N2)and WB/QH/S1355/2019(H9N2)were isolated from chicken in live poultry markets and wild bird droppings collected in Qinghai province in 2019,respectively.To investigate the biological characteristics of the two H9N2 viruses,their genome sequences were analyzed and their pathogenicity was evaluated in mice.Sequence analysis showed that the two H9N2 viruses had the same amino acid sequences of 333PSRSSR↓GLF341 in HA cleavage site without consecutive basic amino acids,which was consistent with the sequence characters of low pathogenic AIV.Genetic evolution analysis indicated that the HA and NA genes of both strains belonged to the Eurasian lineage.Except that the M gene of WB/QH/S1355/2019(H9N2)was highly homologous with that of A/Chicken/Zhejiang/S1074/2016(H7N9)virus,the remaining genes of the two strains were all derived from H9N2 AIV.The NA,PB1 and NP genes of the two H9N2 AIV strains shared 99%-100%nucleotide sequence homology,which revealed that the H9N2 AIVs carried by wild birds may have the possibility of gene recombination with the H9N2 AIVs from poultry.The infectivity in mice revealed that both of viruses could effectively replicate in the turbinates and lungs of mice and that neither of them could be detected in brains,spleens or kidneys of the infected mice.Meanwhile,there was no significant change in body weight or obvious clinical symptoms during the observation period.The above results demonstrated that both of them had low pathogenicity in mice.This study provides data support for the monitoring of H9N2 virus evolution and for evaluating their potential to cause infection in mammals.

关 键 词：禽流感病毒 H9N2 进化分析 致病力 野鸟 

分 类 号：S852.65[农业科学—基础兽医学]