金华市首例甲型H1N1流感死亡病例病毒分离及HA基因序列分析

The HA gene sequence analysis of an influenza A(H1N1) viral strain isolated from the first mortality case in Jinhua,Zhejiang

目的分离甲型H1N1流感病毒,分析金华市首例甲型H1N1流感死亡病例病毒分离株HA基因序列特征,为研究病毒进化、致病性、流行规律提供科学依据。方法采用MDCK细胞和real-time PCR法进行病毒分离、鉴定;提取病毒RNA,通过RT-PCR扩增其HA基因片段,测定核苷酸序列;利用GeneBank中相关序列对病毒分离株A/Jinhua/01/2009(H1N1)进行基因进化树分析。结果从3份咽拭子样本中分离出1株甲型H1N1流感病毒。HA基因序列分析证明:该毒株与2009年大流行株高度同源,与古典型猪流感亲缘性较近,与欧亚地区分离的A/H1N1猪流感病毒及A/H1N1禽流感病毒进化关系较远。结论金华市首例甲型H1N1流感死亡病例分离病毒株与北美流行株高度同源,可能是由古典型猪流感进化而来,与WHO选定的甲型H1N1疫苗候选株同源性较高,对于人季节性流感A/H1N1疫苗可能不敏感。

Objective To analyze the hemagglutinin（HA） gene sequence of an influenza A（H1N1） virus strain isolated from the first mortality case in Jinhua.Methods The H1N1 influenza virus was isolated with MDCK cells and confirmed with the real-time RT-PCR assay.The PCR products of HA gene were sequenced and a phylogenetic tree was generated with the correlated sequences from GeneBank.Results The strain of influenza A/H1N1 virus was isolated from all 3 throat swab specimens of an influenza suspect mortality case.Unfortunately,the virus was the first strain of influenza A/H1N1 confirmed in Jinhua in 2009.The phylogenetic tree demonstrated that the HA gene sequence of the new virus was highly homologous with the sequence of worldwide circulated influenza H1N1 virus in 2009.The strain was more closely related to classical swine influenza virus than swine or avian influenza A/H1N1 virus isolated in Europe and Asia.Conclusion The isolated influenza A/H1N1 virus was similar to the 2009 pandemic strain of influenza virus as well as the influenza A/H1N1 vaccine strain candidate,which was later recommended by WHO.