1995年大连麻疹病毒流行株的部分基因分析

Partial genetic analysis of a measles virus strain epidemiced in 1995 in Dalian

目的本实验以研究麻疹病毒（ＭＶ）为目的，采用反转录聚合酶链式反应（ＲＴＰＣＲ），早期、快速、准确、灵敏地检出ＭＶ，通过对扩增产物的基因分析，判断传染源和传播途径，并研究ＭＶ基因型。方法对１９９５年６月大连地区发生的一起５人的麻疹流行进行ＭＶ检测，用反转录套式ＰＣＲ法分别扩增ＭＶ的核蛋白基因（Ｎ）和基质蛋白基因（Ｍ），阳性对照用长春冻干麻疹活疫苗。对疫苗株长－４７（９４０５）和任意选取的两个标本ＤＬ１Ｃｈｉｎａ９５、ＤＬ２Ｃｈｉｎａ９５的扩增片段进行核酸序列测定，并对核酸序列、相应的氨基酸序列及基因差异进行计算机分析。结果疫苗株和患者标本均扩增得到Ｎ基因３１８ｎｔ，Ｍ基因１８８ｎｔ核酸片段，确证此次为麻疹流行。ＤＬ１Ｃｈｉｎａ９５、ＤＬ２Ｃｈｉｎａ９５有完全相同的核酸序列，属同一流行株，说明此次麻疹流行来自同一传染源，此结果与流行病调查结果相符。此流行株不同于疫苗株长－４７（９４０５）。Ｍ基因的１５２ｎｔ中，流行株５ｎｔ不同于疫苗株，其中有义突变２ｎｔ。Ｎ基因的变异较大，在２８２ｎｔ中，流行株有２１ｎｔ不同于疫苗株，其中有义突变１２ｎｔ。依据Ｎ基因１２３５～１５１６核酸序列，此流行株的基因型分析结果与非洲、欧?

Objective To explore the source and path of measles infection by genotype analysis with RT PCR. Methods There were 5 people suffered from clinical measles in June 1995 in Dalian,China. The virus strains were isolated and the Matrix(M) gene and Nucleocapsid(N) gene were amplified by RT PCR. Changchun measles vaccine strain Chang 47(9405) was used as positive control. PCR products of two random clinical samples DL1China95, DL2China95 and vaccine strain Chang 47(9405) were sequenced. Nucleic sequence, amino acid sequence and gene difference were analyzed by computer. Results 318nts fragment of N gene and 188nts fragment of M gene were amplified from the vaccine virus and the specimens. That confirmed that the cases were caused by MV. The sequences of DL1China95 and DL2China95 were identical in both of the M gene and the N gene. That suggested that the outbreak was originated from a single MV strain. This conclusion was the same as that of epidemiological investigation. The sequences of DL1China95 and DL2China95 were notably different from that of Chang 47(9405). Among the 152nts of the amplified fragment of M gene, there were different 5nts between DL1China95 and Chang 47(9405). Among the 282nts of the amplified fragment of N gene, there were different 21nts between DL1China95 and Chang 47(9405). The epidemic strain was different from the strains widespread in the Africa, Europe and USA. The divergence of the 1235 1516 N gene fragment between DL1China95 and other strains was (7 4 12 8)%. Conclusions The genotype analysis of measles is helpful for studying epidemic regularity and doing better surveillance programs.