2006—2007年广东省登革病毒Ⅰ型分离株E基因序列的分子进化

Phylogenetic analysis of the E gene of Dengue virus isolated in Guangdong province from 2006 to 2007

目的揭示广东省2006—2007年各地登革病毒流行株的遗传关系，探讨其可能来源。方法收集广东省2006年5个流行区、2007年4个流行区登革毒株和近几年广东省分离的登革病毒流行毒株，设计覆盖登革Ⅰ型病毒E（包膜蛋白）基因的3对扩增片段互相嵌套的引物，应用逆转录一聚合酶链反应（RT—PCR）进行扩增，扩增产物纯化后直接进行序列测定，所得序列经拼接成E基因全长序列后，同时与GenBank上获得的登革Ⅰ型病毒E基因序列一起，用MEGA4．1软件进行分析。结果2006年广州流行株来源于越南；阳江、南海流行株来源于阳江本地；汕头、潮州流行株来源于新加坡。2007年流行株都来源于新加坡。结论广东省2006年发生的登革热疫情来源多样，而2007年疫情来自同一源头，近几年广东省流行的登革病毒主要来源于东南亚等国，但在广东省局部地区已形成地方性流行。

Objective To investigate the genetic relationship of the Dengue virus strains isolated in Guangdong province in 2006 and 2007, and to find the sources of these virus. Methods Serum samples of the dengue fever patients from 5 cities of Guangdong province in 2006 and 4 cities in 2007 were collected. Three pairs of primers that specific for amplifying the 3 overlap fragments of E gene of Dengue virus type Ⅰ were designed. RNAs were extracted from C6/36 cells treated with patients＇ serum. E genes were amplified by RT-PCR, purified and then sequenced directly. To obtain the E gene complete sequences, the raw sequences were assembled and edited. Obtained E genes were compared with E genes of other Dengue virus type I published in the GenBank, analyzed by MEGA version 4.1 software. Results In 2006, virus circulating in Guangzhou2006 （EF508203） was closest to Vietnam2006 （EU482539） with 99.3% nucleotides homology, Chaozhou2006 （EF508206） and Shantou2006 （EF508207） strains were closest to Japan2004 （AB178040） and Singapore2006 （EU081280） with 99.5% nucleotides homology, while Yangjiang2006 （EF508205） and Yangjiang2001 （EF508200） were closest to each other and both with 99.5% nucleotides homology to Thailand2001 （AY732482）. All 4 Dengue virus strains circulated in 2007 were closest to Singapore2005 （EU081276） with 99.7% nucleotides homology. Conclusion The Dengue viruses prevalent in 2006 were from different sources while those in 2007 came from the same origin. The data also showed that there was an endemic area of Dengue virus in Guangdong province.