青海省2000-2011年麻疹病毒的分子流行病学研究

Molecular epidemiological study of measles viruses isolated in Qinghai Province during 2000-2011

目的对青海省2000--2011年流行麻疹野病毒进行分子流行病学研究，为消除麻疹提供科学依据。方法使用B95a细胞或Vero／SLAM细胞从2000--2011年青海省6个地市麻疹暴发和散发病例的咽拭子标本中分离的麻疹病毒，用RT—PCR方法扩增N基因羧基末端676个核苷酸片段，再对扩增产物进行核苷酸序列测定和分析，并与我国其他省份流行的麻疹病毒代表株基于N基因羧基末端450个核苷酸片段构建基因亲缘性关系树。结果青海省2000--2011年共分离到19株麻疹病毒，均为H1基因型中的H1a基因亚型。在亲缘性关系树中显示，2000--2005年间流行的麻疹毒株与2009--2011年间流行的麻疹毒株处在两个不同的簇中，提示19株麻疹病毒株至少属于2条病毒传播链，其中2000--2005年间流行的麻疹病毒之后未再监测到。结论青海省2000--2011年间流行的麻疹野病毒以Hla为绝对优势基因亚型，未监测到其他基因型病毒。青海省麻疹病毒不是独立进化的，而是与我国流行的麻疹病毒在共同进化。

Objective To carry out the molecular epidemiological study of the wild-type measles virus isolated in Qingbai Province during 2000-2011, and provide a scientific basis for the measles elimination. Methods Measles viruses were isolated using B95a cell line or Vero/SLAM cell line from throat swabs collected from suspected measles cases during measles outbreak and sporadic in 6 prefectures during 2000-2011. The fragment of 696 nucleotides of N gene earboxy terminal was amplified by using RT- PCR methods. The PCR products were sequenced and analyzed. The phylogenetic tree was conducted with the viruses isolated in viruses from other province. Results Total 19 measles viruses were isolated during 2000-2011 in Qinghai province and all belong to genotype Hl a. The results of phylogenetic tree showed that viruses in 2000-2005 and in 2009-2011 were distributed in two different lineages, and it revealed that these strains belonged to at least 2 viral transmission chains and the viruses circulated during 2000-2005 were not detected after 2005. Conclusion Genotype Hla was the predominant genotype circulated in Qinghai province during 2000-2011. Qinghai measles virus strains had not evolved independently, but coevolved with the measles virus strains in other provinces in China's Mainland. The variation of important amino acid sites of measles virus should be continuous monitored and provide the scientific strategy for the measles elimination.