人感染新型H10N8禽流感病毒基因特征检测分析

目的 了解新型H10N8禽流感病毒基因进化特征，分析血凝素（HA）及神经氨酸酶（NA）关键氨基酸位点变异。方法 2013年12月江西省发现首例人感染新型H10N8禽流感病毒病例，分析其病毒基因核苷酸及氨基酸变异。结果 新型H10N8禽流感病毒[（A/Jiangxi-Donghu/346/2013（H10N8），JX346）]HA基因与A/duck/Hunan/S11205/2012（H10N3）同源性为97.0%，NA基因与A/mallard/Korea/1041/2010（H10N8）的同源性为98.8%，6个内部基因与江西分离的H9N2病毒同源性≥99.0%；JX346的HA的氨基酸裂解位点为PELIQGR↓G，存在5个糖基化位点，在其130环处存在突变为A135T、K137R和S138A；NA存在7个糖基化位点，其抗原决定簇有3个氨基酸位点变异，S199A、A331S和K431N；HA有2个正向选择位点（119N，261I），NA有1个正向选择位点（263V）。结论 新型H10N8禽流感病毒可能由H10N3、H10N8及H9N2禽流感病毒重排产生的一种低致病性禽流感病毒，其关键氨基酸位点的突变可能是人易感染的原因。

Genetic characteristics of novel avian influenza A H10N8 virus isolated in human

Objective To examine evolutionary characteristics of genome of novel avian influenza A H10N8 virus and to analyze the variation of the key amino acid sites of hemagglutinin (HA) and neuraminidase (NA). Methods First human infection case of novel avian influenza AH10N8 virus was diagnosed in Jiangxi province, China in December 2013.The variations in gene nucleotide and amino acid sequence of the novel avian influenza AH10N8 virus strain isolated were analyzed. Results The HA and NA gene sequence of the novel avian influenza A H10N8 virus strain (A/Jiangxi-Donghu/346/2013[H10N8], shortly named JX346) showed high identity with A/duck/Hunan/S11205/2012 (H10N3)(97.0%) and A/mallard/Korea/1041/2010 (H10N8)(98.8%), respectively, and the six internal genes showed a more than 99.0% homology with avian influenza A H9N2 virus strain isolated from Jiangxi province.The amino acid sequence of HA at the hemagglutinin cleavage site of the JX346 was PELIQGR↓G and the HA with five glycosylation sites had substitutions (S199A, A331S, K431N)in the 130 loop.Meanwhile, there were seven glycosylation sites in the NA and three substitutions (S199A, A331S, K431N) in its antigenic epitopes.Selection pressure analysis indicated that 3 positively selected sites in major surface protein of the JX346 strain. Conclusion The novel avian influenza A H10N8 virus strain may be the reassortants of avian influenza A H10N3, H10N8 and H9N2N virus.The substitutions in the key sites of novel avian influenza A H10N8 virus may result in human infection.