湖北省大流行期和流行后期新甲型H1N1流感病毒基因特性分析

目的 了解湖北省大流行期和流行后期新甲型H1N1流感病毒在流行分布、基因进化、抗原表位和耐药位点等方面的差异情况。方法 对2009-2014年湖北省大流行期和流行后期新甲型H1N1流感病毒血凝素和神经氨酸酶的系统进化树、进化速率和氨基酸突变位点进行对比分析。结果 大流行期病毒核酸阳性率大于流行后期，但大流行期病毒血凝素和神经氨酸酶基因进化速率均小于流行后期，且神经氨酸酶进化速率在两个时期都大于血凝素。血凝素抗原表位突变位点K163Q、A186T、S185T和S203T在大流行期与流行后期病毒的分布数和位置存在不同偏嗜，流行期鲜有的H275Y耐药位点在流行后期的三株病毒中被发现。结论 流行后期的新甲型H1N1流感病毒进化速率不断提高，抗原表位和神经氨酸酶抑制剂耐药位点不断积累，防控工作愈加严峻，需进一步加强该病毒基因特性和耐药分析的监测。

Evolutionary feature analysis of influenza A (H1N1pdm09) viruses in Hubei during the pandemic and post-pandemic periods

Objective To investigate the difference of pandemic and post-pandemic influenza A (H1N1pdm09) viruses among epidemiological distribution, evolution, epitope and drug-resistant substitutions. Methods The comparative analysis of pandemic and post-pandemic viruses on phylogenetic trees, evolutionary rate and amino acid mutations of the hemagglutinin, and neuraminidase genes in Hubei from 2009 to 2014 were conducted. Results Positive rate of nucleic acid testing for pandemic viruses was higher than post-pandemic viruses, but evolutionary rate was slower, and evolutionary rate of neuraminidase gene was faster than hemagglutinin gene in the both periods. Amino acid substitutions of hemagglutinin epitopes, such as K163Q, A186T, S185T and S203T, had different distributional and positional preference between pandemic and post-pandemic viruses. Drug-resistance site H275Y substitution was found on three post-pandemic viruses, but little substitution had been reported on pandemic viruses before. Conclusions The evolutionary rate, epitope mutation and drug-resistant substitutions of post-pandemic influenza A (H1N1pdm09) viruses are increasing. The situation of prevention and control is grim. Surveillance of influenza A (H1N1pdm09) viruses should be strengthened especially for genetic feature and analysis of drug resistance.