新疆出血热病毒分子流行病学研究

Molecular epidemiology of Xinjiang hemorrhagic fever viruses

目的研究新疆出血热病毒(XHF)分子流行病学,揭示其与相关病毒之间关系,分析XHF的流行来源和分布特点。方法RTPCR检测20012002年XHF患者和蜱标本中XHF病毒S基因,阳性标本直接进行核苷酸序列测定。计算机软件进行S基因部分片段和S全基因序列同源性比较和S基因、M基因的种系发生树分析。结果不同年份人和蜱来源的病毒S基因部分片段核苷酸序列均显示较高同源性(97.3%～100%)。S基因进化树分析将病毒分成了欧洲、非洲和亚洲3组,其中亚洲毒株由中亚分离株和中国分离株组成,中国所有的XHF病毒S基因(同源性93.0%～99.5%)均集中在一个分枝下形成独立的一组,明显区别于世界上其他地区分离株(同源性81.40%～96.4%)。M基因进化树分析表明序列间差异不完全与病毒分离的地理区域相关。结论S基因分析显示XHF病毒蜱分离株与人分离株遗传背景接近,我国XHF病毒有共同的进化途径和基因结构特点,并具明显的地域性。

Objective To study the molecular biology of Xinjiang hemorrhagic fever （XHF） viruses, to txplorc its relationship with other Crimean-Congo hemorrhagic fever viruses, analyzing the epidemic origin and the tendency of geographic distribution of XHF. Methods The S partial segment from the patient and tick samples collected in 2001 and 2002 was tested by RT-PCR, the positive samples were scqucnsed directly. The nuclcotidc homology of S partial segment as well as the whole segments were analyzed and the phylogcnctic tree of S and M gone segments was drawn by computer. Results All compared sequences of S partial segments from the patient and tick samples showed a high homology of nuclcotidc sequences. Phylogcnctic tree dcvidcd all the analyzed viruses into three groups; Europe, African and Asian group. The Asian group can be divided further into another two branches： the middle Asian branch and the Chinese branch. All the Chinese isolates were clustered into one single group and was easy to be discriminated from the other isolates. The dividing of M segments seemed not complctly related to the geographic orign of the viruses. Conclusion M segment classification was not consistent to the geographic distribution of the viruses. S segments analysis showed the close relationship of genetic background between the patient isolates and the tick isolates. Besides, all the Chinese isolates have the common evolution route and the gone structure characteristics displayed the regional distribution pattern.