一株野鸟源H1N1亚型禽流感病毒的遗传进化特征及其系统学分析

Phylogenetic Variation in Avian Influenza Virus Subtype H1N1 Isolated from Wild Mallard

从2007年秋季在黑龙江省三江国家级自然保护区采集的绿头鸭(Anas platyrhynchos)泄殖腔样品中,分离到一株A型禽流感病毒,亚型鉴定结果为H1N1,命名A/Mallard/Sanjiang/390/2007(H1N1),简称为MD/San-jiang/390/2007(H1N1)。对8个基因片段(PB2、PB1、PA、HA、NP、NA、M、NS)进行了扩增与序列测定,其中HA基因序列的氨基酸裂解位点序列为PSIQSR↓GLFGAI,符合低致病性禽流感病毒(LPAIV)的序列特征。从该病毒基因组的系统进化分析看出:除PA基因属于北美群系禽流感病毒外,其余基因均属于欧亚群系禽流感病毒;与猪流感病毒、季节性人流感病毒、2009年新型H1N1流感病毒的比较来看,亲缘性较远,均处于不同分支,HA亚型分类属于h1.1.2。NP基因与家鸭分离株A/duck/Hokkaido/Vac-3/2007(H5N1)的核苷酸同源性为99.4%,M基因与家鸭分离株A/duck/Hokkaido/W90/2007(H10N7)的核苷酸同源性达99.6%,PB1基因与NP基因和猪分离株A/swine/Korea/C12/2008(H5N2)的核苷酸同源性分别达99.2%、99.1%,提示该病株可能是一个整合了来源于家鸭和猪的多个亚型AIV基因片段的重组病毒。

An avian influenza A virus （AIV）, designated A/Mallard/Sanjiang/390/2007, was isolated from the cloaca sample of a wild mallard collected in Sanjiang Nature Reserve of Heilongjiaug Province, China. The isolate was a HI N1 subtype virus as determined by sequence analysis. Subsequently, the eight full-length genes （PB2, PB1, PA, HA, NP, NA, M and NS） of the virus were amplified and sequenced and the amino acid sequences near the cleavage site within viral hemagglutinin was PSIQSR ↓ GLFGAI, which is consistent with the consensus sequences of the low pathogenic influenza viruses. Phylogenetic analysis shows that the PA gene of the virus clusters within those from the viruses in North American clade, while the remaining genes belong to the Eurasia clade. In addition, the virus is not closely related to swine influenza virus, seasonal human influenza virus or novel influenza virus A/H1N1 in 2009 as demonstrated by the phylogenetic analysis. HA subtype classification indicated that HA gene of the virus was in hi. 1.2. The nucleotide homology of NP geue with A/ duck/Hokkaido/Vac-3/2007（ H5N1 ） AIV was 99.4%, the M gene was 99.6% with A/duck/Hokkaido/W90/2007 （H10N7） AIV, while PB1 and NP genes were 99.2% and 99.1% with A/swine/Korea/C12/2008 （ H5N2 ）, respectively, which suggests that the MD/SJ/390/2007 （H1 N1 ） may be a product of natural reassortment between different sublineages of influenza viruses from domestic ducks and pigs.