甘肃省2009—2012年流感病毒流行特征分析

目的对2009—2012年甘肃省流感监测结果进行分析,为甘肃省的流感防控工作提供科学依据。方法采集全省19家国家级哨点医院门诊流感样病例的咽拭子和各地医疗机构送检流感样暴发疫情咽拭子。采样对象为发病3d之内未使用抗病毒类药物的流感样病例,采集咽拭子,以荧光PCR方法检测病毒核酸,用MDCK进行病毒分离培养。所获得数据采用Excel和SAS软件进行处理,不同样本类型的阳性率的比较使用χ2检验。结果对36 894份流感样病例咽拭子进行核酸检测,检测出流感病毒核酸阳性8 059份,检出率为21.84%,其中4 354份甲型H1N1,1 566份季节性H3N2,92份季节性H1N1,1 656份乙型,391份甲型未分型。按年度分析,2009—2012年流感病毒检出率依次为32.81%、14.10%、7.83%和19.67%;按月分析,在10~12月份甲型流感病毒阳性率及构成比均高于其他月份,阳性率平均为31.33%,构成比为97.61%;2~4月份乙型流感病毒阳性率及构成比分别为16.51%和81.10%。按年龄组分析,<5,5~,15~,25~和≥60岁组病毒核酸检出率分别是13.87%、28.36%、32.33%、16.83%和17.22%,除25~岁组与<60岁组的阳性率差异无统计学意义(P>0.05),其他各年龄组阳性率差异有统计学意义(χ2=26.88~908.11,P<0.01)。对7 073份标本进行病毒分离,分离到病毒1 149株。结论甘肃省2009年以甲型H1N1流感流行为主;2010—2011年流感活动很弱,仅为散发;2012年春季以乙型流感为主,11月开始以甲型H1N1流感及季节性H3N2流感为主。流感流行每年均有一个高峰,病毒型别表现为交替流行的规律,甲型流感是冬季儿童常见的传染病。

Surveillance analysis of influenza from 2009 to 2012 in Gansu province of China

Objective To study the epidemiologic characteristics of influenza in Gansu province of China from 2009 to 2012. Methods Pharyngeal swab specimens of influenza-like illness （ILI） were collected from na- tional surveillance hospitals in Gansu province. Fluorescence quantitative PCR was used to detect the virus nu- cleic acid and specimens were also inoculated on MDCK cell culture to obtain the influenza virus strains. Re- sults From Jan 2009 to Dec 2012, a total of 36 894 specimens were collected and among which, 8 059 （21.84%） were detected ILI positive including 4 354 subtype A （HI pdm N1）, 1 566 subtype H3N2, 92 subtype H1N1, 1 656 subtype B and 391 untypable samples. A total of 1 149 influenza virus strains were isola- ted from nucleic acid positive specimens obtained during years 2009 to 2012, with a positive rate at 32.81 %, 14.10%, 7.83% and 19.67% for each respective year. The proportions of influenza virus infection by age groupsof〈5, 5-, 15-, 25- and ≥60 were 13.87%, 28.36%, 32.33%, 16.83% and 17.22%, respec- tively. Conclusions The predominant strain of influenza virus was subtype A for most winter seasons while subtype B for most spring seasons in Gansu province of China.