2010-2013年杭州地区甲型流感H3N2分子流行病学分析

Epidemiological investigation and migration analysis of Influenza virus A H3N2 in Hangzhou during 2010-2013

目的对2010-2013年杭州地区甲型流感H3N2进行分子流行病学调查分析。方法收集2010-2013年杭州地区H3N2监测样本数据,对样本数据按年份、性别以及年龄进行分组,比较各组之间的差异。查询、整理GenBank中的中国H3N2序列并建立数据集,并对国内H3N2的HA基因及2010-2013年杭州地区H3N2病毒HA、NA序列进行系统生物进化分析。结果 2010-2013年杭州地区H3N2感染率分析,不同年度间H3N2感染率差异具有统计学意义(χ2=14.004,P<0.05),不同性别和年龄组间差异无统计学意义(χ2=3.552,χ2=2.691,P>0.05)。杭州地区2010年与2012、2013年H3N2感染病毒株,在系统进化树上分布存在两个不同分支,且HA序列进化属于广东省H3N2进化的不同时间点的两个分支,在国内H3N2系统进化树上存在一类未见人类感染的病毒分支。结论 H3N2感染无性别选择性及年龄差异,不同年度的感染率存在差异;杭州及我国多省市流行的H3N2感染存在广泛迁徙的现象,今后仍然具有引起高致病性大规模流行的能力,因此应加强各地监测及信息共享,做到早发现和及时防控。

Objective To investigate the epidemiological characteristics and analyze the migration of incidence of infection of Influenza virus A（H3N2）in Hangzhou,Zhejiang from 2010 to 2013.Methods The H3N2 monitoring data during 2010 and 2013in Hangzhou was collected and grouped by the isolation time,gender,and age to compare the differences between each group.Published H3N2 sequences of China were acquired from GenBank,and local dataset was established for further analysis of the biological evolution and migration of the HAgene published in China and the sequences of H3N2 virus collected during 2010-2013 in Hangzhou.Results There was statistically significant difference in the incidence of infection of H3N2 among different years（χ2=14.004,P0.05）,while no significant differences in age and gender（χ2=3.552,χ2=2.691,P0.05）.Analysis of phylogenetic tree based on HA sequences showed that H3N2 viruses isolated in 2010 were different from those in 2012 and 2013,which belonged to two branches at different time points of H3N2 phylogenetic tree of Guangdong province.There was a novel virus of H3N2 which did not infect human in the phylogenetic tree of China.Conclusion There is no difference in the incidence of infection of Influenza virus A between gender or age,but between different years.The infection of Influenza virus A H3N2 was widespreadly migrated in Hangzhou and many other cities of China.There may be large-scale outbreak of H3N2 virus in the future,thus it is necessary to monitor and share information of the outbreaks of H3N2 to prevent and control the epidemics timely.