H6N2亚型禽流感病毒全基因组的序列分析及其致病性研究

Sequence analysis of the entire genome and studies on pathogenicity of a H6N2 subtype avian influenza virus

2008年对我国南方活禽市场进行流行病学监测时从鸭体内分离鉴定出1株H6N2亚型禽流感病毒(AIV)。为了解该病毒DK/GD/S6/08(H6N2)的生物学特征,本研究对其全基因序列进行分析并对SPF鸡和SPF鸭进行致病性试验。结果表明DK/GD/S6/08(H6N2)的HA裂解位点附近的氨基酸序列为340QIETR↓GLF347,符合低致病力AIV的特征。其HA基因与A/duck/Shantou/8365/2005(H6N6)同源性最高;NA基因在颈部无缺失;除M基因外,其他5个内部基因均来源于H6亚型AIV。鸭致病性试验表明DK/GD/S6/08(H6N2)可以感染SPF鸭,并通过泄殖腔排毒,法氏囊等脏器中可以检测到病毒,肺脏、肾脏、法氏囊和脑组织中可见病理变化。鸡致病性试验显示鸡的脑、肺脏、脾脏、法氏囊、肾脏、十二指肠和胰腺均未检测到病毒,咽喉拭子和泄殖腔拭子中未检测到病毒,表明该病毒不能感染SPF鸡。

Avian influenza virus （A1V） DK/GD/S6/08（H6N2） was isolated from duck in a live-bird market in Southern China during the routine epidemiologic surveillance in 2008. Eight genes were sequenced and analyzed. Sequence analysis of the hemagglutinin （HA） gene showed that the virus was categorized as low pathogenic avian influenza （LPAI）, with the typical HA cleavage site of QIETGR ,~ GLF. The HA gene was closely related to A/duck/Shantou/8365/2005 （H6N6） and NA gene had no deletion in the neck region. However, except M gene, other five inner genes were derived from H6 subtype AIV. The pathogenicity test in ducks showed that DK/GD/S6/08（H6N2） was able to infect ducks and caused histopathologic changes, while the same tests in chickens demonstrated that DK/GD/S6/08（H6N2） failed to replicate in chickens.