上海市金山区2015—2019年流感病原学监测结果分析

Pathogenic monitoring of influenza in Jinshan district of Shanghai, 2015-2019

目的了解金山区2015—2019监测年度流行性感冒(流感)的病原学特征,为流感防控提供科学依据。方法收集金山区2015—2019监测年度流感样病例的鼻咽拭子标本,通过Real-time RT-PCR鉴定流感病毒亚型,核酸阳性标本用马丁达比犬肾(Madin-Darby canine kidney,MDCK)细胞和(或)无特定病原体(specific pathogen free,SPF)鸡胚分离培养,对甲型流感进行HA基因分析。结果2015—2019监测年度共采集流感样病例鼻咽拭标本4263份,流感病毒核酸检测总阳性率为23.95%(1021/4263)。其中甲型流感病毒检出阳性数占检测总阳性数的80.99%,主要为甲型H3N2和甲型H1N1。流感病毒检出阳性率及分型情况呈季节分布,各年龄组核酸检测阳性率差异有统计学意义(χ2=83.783,P<0.05),其中60岁以上组阳性率最高30.77%,0~岁组阳性率最低12.10%,不同性别间流感病毒核酸检测阳性率差异无统计学意义(χ2=3.740,P>0.05)。基因进化分析表明金山区甲型H1N1和H3N2流感病毒与疫苗推荐株亲缘性较近,但与国内近几年分离到的甲型流感毒株比较,甲型H1N1和甲型H3N2流感病毒HA基因均存在一定的变异。结论金山区2015—2019年以甲型流感病毒株流行为主。目前的流感疫苗对甲型流感病毒具有预防作用,但不同年份流感病毒HA基因存在一定的变异,应加强流感病毒监测,及时发现病毒的变异情况,提高疫苗的保护作用。

Objective To understand the pathogenic characteristics of influenza in Jinshan district during 2015-2019,and to provide a scientific basis for influenza prevention and control.Methods We collected nasopharyngeal swab specimens from influenza like illness(ILI)cases monitored in Jinshan district during 2015-2019.Real-time RT-PCR was used to detect subtypes of influenza virus,and the specimens positive for nucleic acid test were cultured with Madin-Darby canine kidney(MDCK)cells and/or specific pathogen free(SPF)chicken embryo.The nucleotide sequences of HA genes were analyzed.Results From 2015 to 2019,a total of 4,263 nasopharyngeal swab specimens of ILI cases were collected,and the total positive rate of nucleic acid test of influenza virus was 23.95%(1,021/4,263).The positive detection rate of influenza A virus accounted for 80.99%of the total number of positive cases,of which the main ones were H3 N2 and H1 N1.The positive detection rate and subtypes of influenza virus showed seasonal distribution.Statistically significant difference was observed in the positive rate of nucleic acid test of influenza virus among different age groups(χ~2=83.783,P<0.05),of which the positive rate was found to be the highest(30.77%)in the group aged above 60 years and the lowest(12.10%)in the group aged 0-4 years.There were no statistically significant differences in the positive rate of nucleic acid test of influenza virus between males and females(χ~2=3.740,P>0.05).Genetic evolution analysis showed that HA gene of influenza A H1 N1 and H3 N2 viruses in Jinshan district were closely related to the recommended vaccine strains,but there were some variations in the HA genes of influenza A H1 N1 and H3 N2 viruses compared with influenza A strains isolated in China in recent years.Conclusions Influenza A virus strains dominated in Jinshan district in 2015-2019.The current influenza vaccine has preventive effects on influenza A virus,but the HA gene of influenza viruses in different years has a certain variation.Thus it is necessary to strengthen the monitoring of virus mutation,detect the variation of virus in time,and improve the protective effect of vaccines.