新疆维吾尔自治区2003～2004年麻疹野病毒分离株基因特征分析

Genetic Characterization of Wild-type Measles Viruses Isolated in Xinjiang Uighur Autonomous Region in 2003 and 2004

目的了解新疆维吾尔自治区流行的麻疹野病毒的基因型或亚型特征，为消除麻疹提供科学依据。方法对2003~2004年用健康产婴脐血单个核细胞分离的麻疹野病毒进行分子流行病学分析。采用逆转录-聚合酶链反应对麻疹病毒核蛋白（N）基因羧基（COOH）末端676个核苷酸片段进行扩增，并测定扩增产物的核苷酸序列。通过分析COOH末端450个核苷酸序列构建基因亲缘关系树，并分析毒株变异情况。结果2003年和2004年各分离麻疹病毒3株（XJ03—26、）（J03—27、）（J03—74；XJ04—146、XJ04—150、）（J04—152），除）（J03—26株与沪191株核苷酸差异〈1％，属疫苗相关株A基因型外，其余5株均为H1基因型。其中）（J03—27、）（J03—74、XJ04—150、XJ04—152与H1a。参考株China9322的核苷酸差异为0．5％～1.6％，同属于H1a亚型；XJ04—146与H1b参考株China9475的核苷酸同源性为98．7％，属于H1b亚型。4株H1。毒株分属两组（即XJ03—27与）（J04—150，）（J03—74与）（J04—152），每组内毒株N基因COOH末端450个核苷酸序列几近相同或无差异。结论新疆维吾尔自治区2003~2004年流行的麻疹病毒以H1a亚型为主，亦存在H1b亚型。新疆维吾尔自治区流行的麻疹野病毒间存在较大基因变异，不同年份存在相同麻疹病毒的持续循环传播，需加强麻疹疫苗的预防接种及病毒学监测。

Objective To investigate genetic characterization of wild-type measles viruses isolated in Xinjiang Uighur Autonomous Region in 2003 and 2004, and to provide scientific evidence for controlling and preventing measles effectively. Methods Peripheral blood mononuclear cells （PBMC）obtained from 19 suspected measles cases collected from June 2003 to April 2004 were used to isolate measles virus by cocultivation with phytohemagglutinin（PHA）-stimulated cord blood mononuclear cells（CBMC）. For positive samples, the 676 nucleotides of the C-terminus of the nucleoprotein （N） gene of the measles virus genome were amplified by reverse transcriptionpolymerase chain reaction （RT-PCR）and were sequenced. These sequences were compared with those of other measles reference strains available in GenBank or measles isolates in China using BLAST searches and phylogenetic analyses. Results Six measles virus strains were isolated,3 strains（XJ03-26, XJ03-27, XJ03-74） from 2003 and 3 strains（XJ04-146, XJ04-150, XJ04-152） from 2004. The strain XJ03-26,differed from the Chinese measles vaccine strain S-191 （genotype A）by less than 1% at nucleotide level,and is therefore a vaccine-associated strain. The other 5 strains, XJ03-27, XJ03-74,XJ04-146, XJ04-150,and XJ04-152 were determined to be genotype HI strains, among which XJ03-27, XJ03-74, XJ04-150, and XJ04-152, the nucleotide diversity varied from 0. 5% to 1. 6% compared with the H1a reference strain Chin9322, and were identified as H1a strains ; XJ04-146 showed a nucleotide similarity of 98.7% compared to H1b reference strain Chin 9475, and strain. Additionally, we was identified as Hlb found that there were two sets of strain（XJ03-27 and XJ04-150;XJ03-74 and XJ04-152）, with almost identical nucleotide sequences,circulating in 2003 and 2004. And the two sets had more nucleotide variability（up to 6.1%,27 nucleotides）. Conclusions Genotype HI virus circulated in Xinjiang, China during 2003 and 2004. H1a was the predominant epidemic strain, H1b strain next. There were identical strains circulating in two different years and there were more changes within H1a strains in Xinjiang. These results suggest that a more extensive and active vaccination strategy should be adopt- ed for measles elimination in Xinjiang in China. Continued molecular surveillance of measles viruses should be conducted to observe the change in genotypes over time so as to fully control and eradicate measles globally.