二株鸭源H11N9亚型禽流感病毒的遗传进化及致病性分析

Pathogenicity Analyses of 2 H11N9 Subtype Avian Influenza Isolates from Ducks

为了解从湖南省洞庭湖区鸭群中分离的2株H11N9亚型禽流感病毒变异特点、进化规律及生物学特性,本研究对2株H11N9亚型禽流感病毒的HA、NA序列进行同源性和遗传进化分析,并用2株毒株对SPF鸡进行致病性试验。结果显示,本试验分离到2株H11N9亚型禽流感毒株的HA裂解位点均没有多个连续的碱性氨基酸插入,属于低致病性毒株;HA基因的受体结合位点均非常保守,具有典型的禽源性特征;NA基因序列与在周边国家野鸟中分离的H11N9亚型毒株的氨基酸同源性较高;鼻腔接种SPF鸡后,均能使鸡感染并通过喉头或泄殖腔排毒,但感染的鸡均不表现明显的临床症状,并且不能使同居鸡感染排毒。

To study the genetic variation characteristics, evolution and biological characteristics of two HllN9 subtype avian influenza virus isolates from ducks in Dongting Lake area, we sequenced and analyzed the HA and NA gene homology and genetic evolution, and implemented pathogenicity tests in SPF chickens. The results showed that two H11N9 subtype avian influenza virus isolates belonged to low pathogenic avian influenza virus, because their cracking site did not inset some continuous alkaline amino acid. HA receptor binding sites of the gene were very conservative, with the typical characteristics of avian origin. The amino acid homology of NA genome was higher with other H11N9 subtype avian influenza virus isolated from wild birds in the neighboring countries. All SPF chickens were infected after intranasal inoculation, but the infected SPF chicken did not show obvious clinical symptoms, and cohabiting SPF chickens were not infected.