33株H9N2亚型禽流感病毒分离株分子流行特点的研究

在1998至2007年期间,采集了我国不同地区、不同宿主来源的H9N2亚型禽流感病毒株,应用逆转录聚合酶链反应(RT-PCR)扩增HA基因,获得33株H9N2亚型禽流感病毒的核苷酸序列。结合GenBank中公开发表的其他国内H9亚型禽流感HA基因序列共65株,应用计算机软件绘制进化树,进行H9亚型禽流感病毒谱系全景分析,探索H9亚型禽流感的流行趋势。分析结果表明:这65株的基因进化树主要分为三个系列,每个系列毒株均呈现全国性流行分布;三个系列毒株可在同一时间段内、同一地区发生流行;不同时间的流行毒株虽有变异,但大部分归属于三个系列中。无论从时间的推移上还是地域的转变中,病毒均没有表现出明显的时间演变与地理分布特征,进一步显示了H9亚型禽流感的复杂性和多样性。

Epidemiological Characteristics of 33 H9N2 Subtype Avian Influenza Virus Isolates

To learn the epidemic features of H9N2 subtype avian influenza virus in China,33 H9N2 AIV isolates were collected from different hosts and areas during 1998 to 2007.The HA genes of H9N2 were amplified by RT-PCR.In order to analyze sequence similarities of H9N2 isolates,the HA genes were sequenced subsequently and compared with GenBank data.Based on the sequences of HA gene,the phylogentic tree of H9N2 subtype was analyzed using bioinformatics softwares The epidemiological characteristics was analyzed.The results revealed all the isolates were divided into three clusters and they came from all the areas in China.The distinct genetic diversity among the H9N2 isolates implied no relation with time lapse and geographic distribution.From the isolated strains,three strains sharing high nucleotide sequence identity in three lineages were selected for the vaccine study.The epidemiological investigation provided scientific data and laid the foundation for the develop-ment of the H9N2 subtype polyvalent vaccine.