云南省2006～2010年非脊灰肠道病毒分子流行病学特征分析

Study on the Molecular Typing and Epidemiology of Non-polio Enterovirus in Yunnan Province,China during 2006-2010

为了解云南省非脊髓灰质炎(脊灰)肠道病毒(NPEV)的基因型分布及分子进化特征,对2006～2010年间从急性迟缓性麻痹(AFP)病例中分离到的105株NPEVs进行VP1区部分核苷酸扩增和序列测定。所获得的云南地方株基因序列与各基因型原型株进行核苷酸与氨基酸同源性比较,并与GenBank中选取的代表株构建基因进化关系树。结果分析显示:105株NPEVs分别属于HEV-A、HEV-B、HEV-C,其中HEV-A 18株(7个血清型)所占比例为17.1%;HEV-B 77株(22个血清型)所占比例为73.3%,表明云南省AFP病例中流行的NPEV还是以HEV-B为主;HEV-C 10株(4个血清型)所占比例为9.5%;没有分离到HEV-D组肠道病毒;基因进化树中各种血清型病毒与对应原型株及代表株聚集一起,除CA2、EV90和EV76外,云南地方株与原型株位于不同分支。相同型别的毒株在5年的流行过程中变异程度亦不同,亲缘关系远近不一,表明这些病毒在云南省存在不同的传播链。

In order to explore the genotype distribution and molecular evolution of non-polio enterovirus （NPEVs）in Yunnan Province,the People＇s Republic of China,we sequenced and analyzed the partial VP1 coding region of 105 NPEVs isolated from acute flaccid paralysis （AFP） surveillance in Yunnan province during a 5- year study period from 2006 to 2010. The viral genomes of 105 NPEVs were translated to corresponding amino acid sequences and compared with those of the prototype strains, and the phylogenetic tree was constructed among these VP1 nucleotide sequences and other prototype strains from GenBank. Analysis showed that 18 isolates were classified into 7 serotypes of human enterovirus A species, while 77 isolates into 22 serotypes of B and 10 isolates into 4 serotypes of C species. However, we did not isolate any viruses which belonged to human enterovirus D species. Thus, under AFP surveillance, human enterovirus B species accounted for 73.3; of the 105 isolates and was considered as the predominant one,followed by human enterovirus A（17.1%） and human enterovirus C（9.5 %）. Phylogenetic analysis showed that various serotypes of the virus and the corresponding prototype strains or other representative strains clustered into the same grooup, however, Yunnan strains and prototype strains were located in the different branches （except CA2.EVg0 and EV76）. The degree of variation was different even among the same genotype strains. This report showed that different genotype strains spread widely in Yunnan Province.