浙江省首例人禽流感病例的病原学与分子生物学研究

Pathogenicity and Molecular Characterization of the H5N1 Influenza Virus Isolated from the First Human Case in Zhejiang Province

为确认浙江省首例疑似人禽流感病例,进行病原学分析,对患者气管吸出物进行核酸RT-PCR、荧光定量RT-PCR检测以及病毒分离,并对患者血清进行HI抗体测定。结果表明:患者气管吸出物H5N1亚型和A型流感病毒特异核酸均呈阳性,分离到禽流感病毒A/Zhejiang/16/06(H5N1)株;双份血清中禽流感病毒(H5N1)HI抗体滴度分别为1:320和1:640,从病原学和血清学上证实为人禽流感病例。分离毒株测序结果显示,A/Zhejiang/16/06(H5N1)株在HA裂解位点为多个碱性氨基酸,符合高致病性禽流感病毒特征;该毒株的HA、NA、PB2、NP、M和NS基因序列均为禽源,与2005年我国福建、安徽等地禽流感病毒分离株高度同源,而与越南、泰国以及香港1997年分离到的禽流感病毒株之间存在明显差异。

In order to confirm the etiology of the first suspected human case of the highly-pathogenic avian influenza virus and to perform the pathogenicity studies, a tracheal aspirate specimen was tested by RT-PCR, Real-time PCR and virus isolation. In addition, the HI （hemagglutination-inhibition） antibody in serum samples was assayed. The results showed that RNA extracted from the tracheal aspirate specimen was positive for H5N1 avian influenza virus and influenza virus type A. The H5N1 avian influenza virus was named A/Zhejiang/16/06 （H5N1）. The titers of HI antibody for H5N1 avian influenza virus were 1：320 and 1： 640, respectively. Both the pathogenic and serologic tests confirmed the human case of H5N1 avian influenza virus infection. The results of HA （hemagglutination） gene sequencing revealed that there were multiple basic amino acids at the cleavage site of HA gene associated with highly pathogenic H5 avian virus. The HA、 NA、PB2 、NP、M and NS genes were all of avian origin and were very similar to that of H5N1 avian influenza virus isolated from Fujian and Anhui provinces in 2005. However, there were obviously differences compared with the strains isolated from Vietnam, Thailand and Hong Kong in 1997.