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目的了解江西省2007年乙型流感病毒流行情况的分子基础。方法采集监测医院和疑似流感疫情的流感样病例鼻咽拭子标本进行流感病毒分离,对分离到的B型流感病毒进行核酸的提取,采用逆转录-聚合酶链反应(RT-PCR)扩增病毒HA1基因后进行核苷酸序列测定,用DNAStar5.0、BioEdit(Version5.0)、Mega生物软件对测序结果进行分析处理,推导出氨基酸序列,进行基因特性分析。结果2007年分离到B型流感病毒91株,其中68株Yamagata系和23株Victoria系;6株Yamagata系和4株Victoria系B型流感病毒分别与WHO推荐的疫苗株B/Shanghai/361/2002(Yamagata系)和B/Malaysia/2506/2004(Victoria系)的HA1序列比对,结果为:Yamagata系B型流感病毒HA1区域核苷酸平均替换数为23.3个,平均点突变率为2.30%,氨基酸替换数在7～9个,同源性为95.2%～96.3%,所有毒株均在6个相同的氨基酸位点发生了相同的替换;Victoria系B型流感病毒HA1区域核苷酸平均替换数为8.5个,平均点突变率为0.84%,氨基酸替换数在3～4个,同源性为98.95%～99.48%,所有毒株均在3个相同的氨基酸位点发生了相同的替换。结论2007年Victoria系B型流感病毒HA1基因特性有所改变,疫苗仍有预防效果,但是B型流感流行趋势发生了改变,Yamagata系比Victoria系更活跃,B/Malaysia/2506/2004(Victoria系)疫苗推荐株对江西省B型流感保护效果不佳。
Objective To understand the molecular basis of the prevalence of influenza B virus in Jiangxi Province in 2007. Methods Nasopharyngeal swab samples of influenza-like cases in hospitals and suspected influenza epidemic were collected for influenza virus isolation. Nucleic acid was extracted from influenza virus type B and amplified by reverse transcription-polymerase chain reaction (RT-PCR) The HA1 gene of the virus was sequenced, and the sequencing results were analyzed by using DNAStar5.0, BioEdit (Version5.0) and Mega biological software to deduce the amino acid sequence and analyze the gene characteristics. Results A total of 91 strains of influenza B virus were isolated in 2007, of which 68 strains were Yamagata strains and 23 strains were Victoria strains. Six strains of Yamagata strain and four strains of Victoria strain were associated with WHO vaccine strains B / Shanghai / 361/2002 (Yamagata line) and B / Malaysia / 2506/2004 (line Victoria line). The results showed that the average number of nucleotide substitutions in HA1 region of Yamagata strain B was 23.3 and the average point mutation rate was 2.30% , The number of amino acid substitutions ranged from 7 to 9 and the homology was 95.2% to 96.3%. All the strains had the same substitutions at the same 6 amino acid sites. The average number of nucleotide The number of substitutions was 8.5, the average point mutation rate was 0.84%, the number of amino acid substitutions was 3 ~ 4, and the homology was 98.95% ~ 99.48%. All strains were replaced by the same amino acid at the same three sites . Conclusion The characteristics of HA1 gene of influenza B virus in Victoria have been changed in 2007, and the vaccine still has a preventive effect. However, the epidemic trend of influenza B is changed. Yamagata is more active than Victoria. B / Malaysia / 2506/2004 (Victoria ) Vaccine recommended strains of type B influenza in Jiangxi Province to protect the poor.