2015年四川省麻疹病毒分子流行病学特征分析

摘要

目的 分析四川省2015年流行的麻疹病毒的基因型别和核蛋白基因特征,了解不同基因型别麻疹病毒在省内流行情况.方法 采集疑似麻疹病例咽拭子标本,用Vero/SLAM细胞分离病毒.对分离培养阳性毒株,采用逆转录-聚合酶链反应(RT-PCR)扩增核蛋白N基因片段并进行序列测定和分析.结果 从971份疑似麻疹病例咽拭子标本中分离得到398株麻疹病毒.397株分离株为H1基因型,与H1基因型参考株核苷酸同源性为96.2％-98.0％;在进化树上呈现为2个分支,分支间平均核苷酸差异率为2.0％.1株分离株为A基因型,与A基因型参考株核苷酸同源性为98.0％.结论 H1基因型为2015年四川省本土流行麻疹病毒的优势基因型;近年来四川省内流行的毒株未发生较大变化,但存在一定核苷酸差异,呈现2个传播链,需进一步加强监测.%Objective To analyze the genetic characteristics of measles virus in Sichuan province in 2015.Methods Measles virus was isolated from throat swab specimens collected from suspected measles cases.Nucleotide sequences coding for C terminus of nucleoprotein were amplified by RT-PCR and sequenced for phylogenetic analysis.Results 398 measles virus isolates were obtained from 971 throat swab specimens.Phylogenetic analysis showed that 397 belonged to H1 genotype,the sequences homologies were 96.2％-98.0％ compared with H1 genotype reference strain;and all those isolates separated into 2 clusters in phylogenetic tree with the average nucleotide divergence of 2.0％.1 isolate belonged to A genotype,and shared 98.0％ nucleotide homology compared with A genotype reference strain.Conclusions H1 genotype virus remained predominant circulating in Sichuan Province.There was no much genetic variation in N gene.But a minor nucleotide divergence existed between different clusters,leading to 2 transmission chains.