2005～2006年湖南省人感染高致病性禽流感(H5N1)实验室诊断及病毒基因特性研究

为了对2005~2006年湖南省2例不明原因肺炎病例进行实验室诊断,确定病因以及对其进行病原学研究,采集病例呼吸道标本和血清标本,对呼吸道标本采用实时荧光定量逆转录聚合酶链式反应(Real-time RT-PCR)和逆转录聚合酶链式反应(RT-PCR)方法检测H5亚型禽流感病毒核酸,对血清标本采用血凝抑制试验检测特异性抗体,并对其中1例死亡病例(病例2)的肺穿刺物标本进行病毒分离,所获毒株予以测序及同源性分析。结果显示,2例病例H5亚型禽流感病毒核酸检测均为阳性,病例1恢复期血清H5N1特异性抗体阳性,并且较急性期血清呈4倍以上增长;病例2急性期血清特异性抗体阴性,2例均为人感染高致病性禽流感病毒(H5N1)确诊病例。从病例2分离得到毒株A/Hunan/1/2006,测序及分子特性分析表明,其8个基因片段均为禽源,且与湖南本地禽类分离的病毒相似,并未与人流感病毒发生基因重组或产生显著变异。

Laboratory Diagnosis and Molecular Characterization of Highly Pathogenic Avian Influenza Virus (H5N1) in Human in Hunan Province in 2005-2006

To determine the etiologic agents of two atypical pneumonia human cases in Hunan Province in 2005-2006 and to study their pathogenic potential,the patients' respiratory tract samples and sera were collected.The respiratory tract samples were tested by real-time RT-PCR and RT-PCR methods,and the sera by hemagglutination-inhibition assay.Virus was isolated from case 2 and its genome was sequenced and analyzed.Results showed the H5 nucleic acid tests of two cases were positive.The H5-specific antibody titer of the convalescence serum of case 1 showed a 4-fold greater rise than that of the acute phase.And case 2's antibody titer of acute phase was negative.The two atypical pneumonia cases were confirmed as the avian influenza A(H5N1) infection cases.Viral strain A/Hunan/1/2006 was isolated from case 2.Phylogenetic and molecular analysis suggested that 8 gene segments of A/Hunan/1/2006 originated from avian viruses.And A/Hunan/1/2006 was similar with viruses isolated from avian in Hunan Province.The isolated virus did not recombine with human influenza viruses and no obvious variation was observed.