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目的为了解不同省(自治区、直辖市,下同)2003年流行的麻疹野病毒是否存在基因型或亚型的差异。方法对2003年15个省分离的107株麻疹病毒进行了分子流行病学研究,对同一年份不同省流行的麻疹野病毒的基因特征及分子差异做了进一步的分析。用逆转录-聚合酶链反应(reversetranscriptpolymerasechainreaction,RT-PCR)从107株麻疹病毒中扩增出核蛋白(nucleoprotein,N)基因羧基(COOH)末端450个核苷酸片段。通过对扩增产物进行核苷酸序列测定和分析,构建基因亲缘性关系树,进行遗传距离分析。结果106株为麻疹病毒H1基因型;1株属于A基因型,为沪191(S191)疫苗株。106株H1基因型毒株分成2个亚型,101株为H1a,5株为H1b基因亚型。2003年H1b亚型主要流行于海南、四川、上海、贵州省;而H1a在全国广泛分布;未发现H1c基因亚型,该亚型1993~1994年曾是北京、山东、河北、湖南省流行的优势毒株。对比2003年与1993~2002年流行的麻疹病毒基因亚型,H1a呈上升趋势,H1b亚型在所有H1基因型中的比例由1995~2002年的24·3%下降到2003年的4·7%,而H1c亚型逐渐消失。对2003年分离的病毒进行省内和不同省间遗传距离的比较证明,各省内的毒株变异范围在0%~6·1%(0~27个核苷酸差异);各省间的变异范围在0%~4·3%(0~20个核苷酸差异);省内差异最大值大于省间差异。结论中国最近11年来流行的麻疹病毒基因亚型趋势为:H1a呈上升趋势,逐渐成为优势亚型;H1b亚型逐年降低转为弱势;H1c亚型逐渐消失。2003年麻疹变异毒株呈散在分布,无明显地域性。同时表明,中国的麻疹流行是由H1a和H1b中的许多不同病毒株造成的多个传播链引起的。讨论了在中国继续开展麻疹病毒分子流行病学监测的必要性和紧迫性,并展望了分子流行病学监测对于中国控制和消除麻疹的应用前景。
Purpose To find out whether the genotypes or subtypes of measles wild virus in different provinces (autonomous regions, municipalities directly under the Central Government, the same below) are prevailing in 2003. Methods The molecular epidemiology of 107 measles viruses isolated in 15 provinces in 2003 was studied. The genetic characteristics and molecular differences of wild measles virus in different provinces in the same year were further analyzed. Nucleotide (450) nucleotides (COOH) of nucleoprotein (N) gene were amplified from 107 measles viruses by reverse transcriptase polymerase chain reaction (RT-PCR). Through the nucleotide sequence determination and analysis of the amplified product, the gene relationship tree was constructed and the genetic distance was analyzed. Results 106 strains of measles virus H1 genotype; a strain of A genotype, Shanghai 191 (S191) vaccine strain. 106 strains of H1 genotypes were divided into two subtypes: 101 strains were H1a and 5 strains were H1b subtype. In H1 2003, H1 subtype mainly prevailed in Hainan, Sichuan, Shanghai and Guizhou Provinces; while H1a was widely distributed throughout the country; no H1c subgenotype was found. This subtype had been popular in Beijing, Shandong, Hebei and Hunan provinces from 1993 to 1994 Advantage strains. Compared with the genotypes of measles virus prevalent in 2003 and from 1993 to 2002, H1a was on the rise. The proportion of H1 subtype in all H1 genotypes dropped from 24.3% in 1995-2002 to 4.7 in 2003 %, While the H1c subtype disappeared gradually. Comparison of the genetic distances between the isolates in the province and in different provinces in 2003 showed that the variation range of isolates in each province ranged from 0% to 6.1% (ranged from 0 to 27 nucleotides). The variation range In 0% ~ 4.3% (0 ~ 20 nucleotide differences); the maximum difference between provinces is greater than the provincial differences. Conclusion The prevalence of measles virus subtypes in China in the recent 11 years is as follows: H1a is on the rise and gradually becomes the predominant subtype; the H1b subtype is gradually reduced to the weakest and the H1c subtype disappears gradually. Measles variants were scattered in 2003, no obvious regional. It also shows that the spread of measles in China is caused by multiple transmission chains caused by many different strains of H1a and H1b. Discussed the necessity and urgency of continuing the molecular epidemiological surveillance of measles virus in China and looked into the application prospect of molecular epidemiological surveillance in China to control and eliminate measles.