柯萨奇病毒A16型的B1a和B1b两个分支在内蒙古自治区共同流行

B1a and B1b Evolutionary Branch of Coxsackie virus A16 Co-prevailed in Inner Mongolia Autonomous Region

研究2010年引起内蒙古自治区手足口病流行的柯萨奇病毒A组16型(Coxsackie virus A16,CVA16)的分子流行病学特征。采集内蒙古自治区12个盟市门诊就诊的888名手足口病患者粪便和咽拭子标本共921份,进行病毒分离,然后利用实时荧光PCR对阳性分离物进行CVA16的鉴定。从临床症状分别为普通型、重型和死亡病例的临床标本中分离的CVA16中随机选取50株代表株进行VP1编码区扩增及核苷酸序列测定和分析,与其他各基因型和基因亚型的CVA16构建亲缘进化关系树。921份标本共分离出82株CVA16,分离率为8.90%,其中从重症病例分离出3株CVA16,从死亡病例中分离出1株CVA16。50株内蒙古CVA16代表株在核苷酸水平上与1998年以来中国大陆CVA16分离株的同源性都较高,尤其与2009年北京株和2010年河南株的同源性最高,分别为96.18%～98.88%和94.94%～98.76%;但与2007年内蒙古流行株存在一定的差异,同源性仅为91.68%～96.52%;亲缘进化关系树显示,所有内蒙古CVA16株都属于B1基因型的两大进化分支B1a和B1b,并处于不同的簇中,它们之间的核苷酸和氨基酸同源性分别为89.99%～100%和98.31%～100%,表现为CVA16分离株属于多个病毒传播链。2010年从内蒙古自治区不同临床症状手足口病病例分离的CVA16流行株属于B1基因型的两大进化分支B1a和B1b,两个进化分支的CVA16在内蒙古自治区共同进化和流行。

To study on the molecular evolution of Coxsackie virus A16 （CVA16）isolated from clinical specimens of Hand, foot and mouth Disease（HFMD） patients in Inner Mongolia in 2010. A total of 921 clinical specimens including stools, throat swabs and vesicle fluids were collected from 888 HFMD patients in outpatient service in Inner Mongolia and viral isolation was then performed, the positive viral isolates were identified by using the real-time PCR method detecting CVA16. A total of 50 CVA16 isolates were selected from the patients presenting mild symptoms, severe symptoms and the death patients randomly, and the VP1 coding regions of representative CVA16 isolates were amplified and sequenced. Finally the phyloge- netic tree was constructed among the VP1 coding regions of the different genotypes and subgenotypes of CVA16 strains. Eighty two viruses were isolated form 921 clinical specimens, the positive rate was 8.90% ,of which 3 viruses were isolated from severe cases and 1 viruses was from death cases. The nucleotide acid of 50 representative CVA16 strains in Inner Mongolia were closed to CVA16 strains isolated from China's Mainland since 1998, especially from Beijing in 2009 and from Henan in 2010, the identity were 96.18%-98.88% and 94.94%-98.76%, respectively. There was a little difference in the nucleotide acid between the CVA16 strains from Inner Mongolia in 2010 and in 2007, the identity were 91.68%-96.52% . The phylogenetic tree showed that all CVA16 strains clustered within Bla and Blb evolution branch of B1 genotype. There was slight difference in the nucleotide and the amino acid in VP1 region among the 50 Inner Mongolia CVA16 strains, the identity were 89.99%-100% and 98.31%-100%, respectively, indicating that these strains belonged to many different viral transmission chains. The CVA16 strains circulated in Inner Mongolia in 2010 were all belong to Bla and Bib evolution branch of B1 genotype, and the two evolutionary branchs of Coxsackie virus A16 were co-evolved and co-prevailed in Inner Mongolia Autonomous Region.