1999-2007年佛山市流感病毒活动情况及甲3亚型病毒HA1基因分析

目的总结1999-2007年佛山市流感病毒流行情况,分析甲3亚型（H3N2）毒株流行与其HA1基因进化的关系。方法用MDCK细胞分离流感病毒,培养后血凝阳性者进行型别鉴定。随机抽取每年2～3株甲3亚型毒株的细胞培养物提取RNA后进行HA1基因的逆转录,对其核苷酸和氨基酸序列及亲缘关系进行分析。结果甲型和乙型流感病毒在佛山市人群中同时流行。甲型流感毒株是人群感染流感的主要型别。HA1区氨基酸序列与历年的流感疫苗推荐株相比,点突变率为0.3%～6.08%。发生替换的重要位点包括了抗原决定簇的17个位点、抗体结合部位的10个位点和1个糖基化位点。结论佛山市的甲1和甲3亚型流感毒株活动呈此起彼伏的优势株转换现象。甲3亚型新旧毒株交替迅速,大致按照毒株分离的年代聚类成进化树的不同小侧枝,表明新的流行株出现后可能迅速突破地域局限。提示地区实验室及时监测和研究流感毒株的发生和发展是流感监测网络建设的基础。

Characteristic of Influenza Epidemics and Study of Hemagglutinin Gene of Influenza A（H3N2） Virus Isolated in Foshan in 1999-2007

Objective To study the characteristic of influenza epidemics and analyze the genetic and antigenic feature of HA1 gene of influenza A（H3N2） virus circulated in Foshan from 1999 to 2007. Methods According to the result of the hemagglutination inhibition（HI） test, viral RNA were extracted from culture fluid of the influenza A （H3） virus strain. HA1 gene was obtained by RT-PCR and sequenced. Results Both influenza A and B viruses were observed cocirculating in human in Foshan during this period, with A virus being the dominant circulating strain. Comparison between 22 H3N2 viruses strains in Foshan and the recommended vaccine strains showed 0.30%-6.08% single amino-acid substitution, including 17 substitutions in antigenic determinant and 10 substitutions in antigen binding sites. Conclusion Influenza H3N2 and H1N1 viruses took turns to be the dominant circulating species in these years. New H3N2 virus strains substituted old ones quickly, and clustered into different branches according to the isolated time, which indicated that new virus strains could rapidly become widespread, therefore local laboratories should play an important role in influenza virus surveillance.