水禽源H3亚型禽流感病毒分离鉴定及其对鸭的致病性研究

Isolation of Waterfowl Derived H3 Subtype Avian Influenza Virus and Its Pathogenicity to Duck

为调查某蛋鸭养殖场发生的以急性产蛋下降和呼吸道症状为特征的传染性疾病病原,研究对发病鸭群进行病原分离鉴定、全基因组演化分析以及动物回归试验。结果显示:引起蛋鸭发病病原为H3N6亚型禽流感病毒(AIV);该病毒HA和NA基因来源于欧亚谱系野鸟源低致病性AIV,内部基因与当前流行的2.3.4.4b分支H5Ny亚型AIV具有较高的同源性;该病毒对SPF鸭高度易感,感染雏鸭出现呼吸道症状以及神经症状,死亡率40%,引起肺脏等多脏器严重病理损伤,病毒可在气管、肺脏、小肠和脑中有效复制,通过口咽和泄殖腔长时间(11d)排毒,并且在鸭之间接触传播。综上所述,试验分离的新型重组H3N6亚型AIV对鸭致病性较强,并具有一定的传播能力,对水禽养殖业具有一定威胁。

In order to explore the pathogen of an infectious disease characterized by respiratory symptoms and acute egg-laying rate decline in a duck flock,virus isolation,identification,sequence analysis,and duck infection experiment were carried out in this experiment.The results showed that the pathogen was H3N6 subtype avian influenza virus(AIV),which was evolving as a multiple reassortment event,and its HA and NA gene were from lowly pathogenic AIVs of Eurasian lineage.The internal genes were highly homology with clade 2.3.4.4b H5Ny AIV circulating in migratory birds and domestic waterfowl.The novel H3N6 AIV was highly susceptible to SPF duck.Infected ducks showed respiratory symptoms,neurological symptoms and caused 40%mortality.The pathological changes were observed in multiples organs,and the virus could be detected from the oropharynx and cloaca for 11 days,and also replicated efficiently in trachea,lung,small intestine and cerebrum,which was transmitted by contact between ducks.In conclusion,the novel reassortment H3N6 AIV was highly pathogenic to duck and had a certain ability of transmission,which posed a threat to waterfowl industry.