中国2000～2001年流行性感冒流行概况

Influenza activity in China from 2000 to 2001

目的 了解中国 2 0 0 0～ 2 0 0 1年流行性感冒 (流感 )流行及抗原性变异情况。方法 鸡胚传代病毒用于抗原性分析 ;病毒液提取RNA进行逆转录 聚合酶链反应 (RT PCR) ,扩增产物纯化后测序。然后用MegAlign(Version1.0 3 )和Editseq(Version3 .69)软件进行基因种系发生树分析。结果 2 0 0 1年流行的H1N1亚型病毒血凝素蛋白重链 (HA1)区氨基酸序列与A 上海 7 99(H1N1)相比 ,在抗原决定簇D区的第 190位发生了氨基酸替换 ;基因种系发生树表明 2 0 0 1年的H1N1亚型流感病毒存在基因特性不同的两系病毒株。国内人群中仍然同时流行着两种抗原性明显不同的B型流感病毒 (Yamagata系和Victoria系 ) ,Yamagata系病毒占大多数 ,Victoria系的HA1区基因与B 山东 7 97毒株相比 ,其 197和 199位氨基酸发生了替换。B型的基因种系发生树也证实Victoria系病毒株的抗原性改变。 2 0 0 0年分离的H3N2亚型流感病毒的HA1区氨基酸序列与A 悉尼 5 97(H3N2 )间有 7～ 8个氨基酸的差异 ;2 0 0 1年分离的H3N2病毒株与 2 0 0 0年的病毒株相比 ,又在 83、186、2 0 2、2 2 2位发生了氨基酸替换 ,表明H3N2亚型病毒株间的抗原性发生了较明显的变异。结论 2 0 0 0～ 2 0 0 1年中国流感的流行情况较为平静 ;H3N2亚型的抗原性发生?

Objective To understand the epidemics and antigenic drift of influenza viruses in China from 2000 to 2001. Methods The viruses were grown in embryonated hen eggs with 9-10 days old. The egg allantoic fluids with influenza viruses were used. Virion RNA was transcribed into cDNA by reverse transcriptase while cDNA amplified by PCR. Producs of PCR were purified. RNA sequence analysis was then performed. Finally, phylogenetic analysis of the sequencing data was performed with MegAlign (Version 1.03) and Editseq (Version 3.69) software. Results Data from comparison of amino acid sequence on HA1 domain of HA protein molecule between H1N1 viruses isolated in 2001 and A/Shanghai/7/99 (H1N1) strain indicated that there was only one difference of amino acid located at 190 position (antigenic determinant D). However, phylogenctic analysis showed that there were two distinguishable genetically lineages of H1N1 viruses co-circulating in men in China in 2001. Two antigenically distinct genetic lineages of influenza B viruses were still existing in men in China. Most of influenza B viruses were Yamagata-like strain and there were two different amino acid sequences located at 197 and 199 position on HA1 domain of HA protein molecule, between Victoria-like virus isolated and B/Shandong/7/97 strain. When comparing amino acid sequences on HA1 protein domain of H3N2 viruses isolated in 2000 with those of A/Sydeney/5/97 (H3N2) virus,it was revealed that there were 7-8 differences of amino acid sequences between them. However, there were four differences related to amino acid sequences on HA1 protein domain between H3N2 viruses isolated in 2000 and in 2001. These results were further demonstrated by analysis of pholygenic tree. Conclusions Influenza was not prevalent in China from 2000 to 2001. The antigenic drifts of H3N2 and B/Victoria-like viruses occurred. Two antigenically distinct genetic lineages of influenza B viruses were still co-circulating in men in China. Two genetically distinct lineages of influenza A(H1N1) virus were also co-circulating in men in China.