西藏自治区儿童埃柯病毒29型分子流行病学分析

Ananlysis on the molecular characteristics of ECHO29 virus in Tibet

目的 研究西藏自治区1999-2000年≤5岁儿童埃柯病毒29型（Echovirus 29,ECHO29） VP1区编码基因特征及其分子流行病学特点.方法 选取1999-2002年从西藏自治区急性弛缓行麻痹（acute flaccid paralysis,AFP）病例和≤5岁到儿童医院就诊儿童及部分健康儿童的659份粪便标本中分离的7株ECHO29病毒,进行核糖核酸（RNA）提取,VP1编码区逆转录-聚合酶链反应（RT-PCR）,PCR产物的核苷酸序列测定和分析.结果 共分离出7株ECHO29病毒,其中5株是从1999年标本中分离到的;另2株是从2000年标本分离到的,其他年份未分离到ECHO29.7株ECHO29病毒VP1区基因全长都是876 bp,翻译的氨基酸全长为292 aa.所测7株ECHO29病毒序列之间同源性为75.41％ ～ 99.3％.所测序列与ECHO29原型株JV-10相比,核苷酸同源性为77.1％ ～81.23％,氨基酸同源性为71.26％ ～ 79.69％.所构建的ECHO29病毒遗传进化树将已知的ECHO29病毒划分为4个基因型,西藏自治区的7株ECHO29病毒序列分别属于Genotype A和C.结论 首次报告的西藏自治区1999、2000年儿童中流行的ECHO29病毒为2个不同基因型,1999年流行的病毒属于Genotype C,2000年流行的病毒属于Genotype A,西藏自治区1999、2000年ECHO29病毒流行为不同基因型.2001-2002年未发现ECHO29病毒的持续流行。

Objective To study thegenetic and molecula repid emiological characteristics of ECHO29 virusVP1 region coding in Tibet under 5-year-old children in 1999-2000.Method 7 strains of ECHO29 viruses isolated from 659 stool specimens of AFP cases and under 5-year-old patients and some healthy children in Tibet in 1999-2002 were used to extract ribonucleic acid （RNA） while VP1 coding area were amplified by reverse transcription-polymerase chain reaction （RT-PCR） and the nucleotide sequence of PCR products were determined and analyzed.Result A total of 7 strains ECHO29 viruses were isolated from the stool specimens and identified.5 strains were isolated from specimens in 1999 while the other 2 strains isolated from samples in 2000.The complete nucleotides sequence of VP1 region of 7 strains ECHO29 viruses were 876nt coding 292 amino acids.The sequence homology of 7 strains detected ECHO29 viruses was between 75.41%-99.3% while amino acid homology was between 71.26%-79.69%.The phylogenetic tree of ECHO29 viruses showed 4 genotypes which the isolates from Tibet were belong to Genotype A and C.Conclusion It was first reported that the popular ECHO29 viruses in children in Tibet were proposed to 2 different genotypes in 1999 and 2000.The popular ECHO29 virus epidemic in 1999 was belong to Genotype C,while popular ECHO29 virus in 2000 belong to Genotype A.ECHO29 virus increasingly popular was not found in 2001 and 2002.