2018年北京市朝阳区流行性感冒流行特征及病原学监测分析

Epidemiologic characteristics and etiology surveillance of influenza in Chaoyang district of Beijing in 2018

目的了解北京市朝阳区流感样病例(ILI)流行性感冒(流感)病毒(Flu A/B)的病原谱及流行特征,为制定科学有效的流感防控措施提供依据。方法采集2018年1月1日-2018年12月31日北京中日友好医院、首都医科大学附属北京朝阳医院2家哨点医院就诊的ILI的咽拭子样本,采用多重实时荧光PCR法检测Flu A/B。采用χ^2检验或Fisher's确切概率法比较不同性别、年龄及月份Flu A/B的检出情况,对ILI数与Flu A/B、Flu A及Flu B检出率,Flu A与Flu B检出率进行Spearman秩相关分析。结果2018年北京市朝阳区共报告ILI 2073例,其中,男性占43.37%,女性占56.63%,平均年龄(38.59±16.34)岁。Flu A/B单一阳性率为17.56%(364/2073);Flu A型占63.46%(231/364),其中,H1N1亚型占65.37%(151/231),H3N2亚型占34.63%(80/231);Flu B型占36.26%(132/364),其中,B-Victoria系占20.45%(27/132),B-Yamagata系占79.55%(105/132);混合感染率为0.05%(1/2073)。时间分布上,不同月份Flu A/B核酸检测阳性率及Flu A/B型别的分布不同,差异有统计学意义(χ^2=522.021,P<0.05;χ^2=137.765,P<0.05)。性别分布上,不同性别Flu A/B核酸检测阳性率及Flu A/B型别的分布差异无统计学意义。年龄分布上,不同年龄间Flu A/B型别的分布差异无统计学意义。ILI数与Flu A/B(rs=-0.242)、Flu A(rs=-0.102)及Flu B(rs=-0.156)阳性检出率均无相关性(P均>0.05),Flu A与Flu B检出率呈正相关(rs=0.758,P<0.05)。结论2018年北京市朝阳区流感流行的优势毒株为H1N1亚型和B-Yamagata系,B-Victoria系和B-Yamagata系检出率在时间分布上差异有统计学意义,在本地区首次发现Flu A与Flu B阳性检出率呈正相关,流行持续时间与优势株的型别构成有关。

Objective To understand the pathogenic spectrum and epidemiological characteristics of influenza-like illness(ILI)influenza virus(Flu A/B)in Chaoyang district of Beijing,China.Methods Samples of ILI throat swabs from 2 sentinel hospitals of Beijing China-Japan Friendship Hospital and Beijing Chaoyang Hospital affiliated to Capital Medical University from January 1,2018 to December 31,2018 were collected.Fluorescence detection was performed by multiplex real-time PCR.χ^2 test or Fisher exact probability method was used to compare the detection of Flu A/B in different genders,ages and months.The detection rate of ILI number and Flu A/B,Flu A and Flu B were detected.Spearman rank correlation analysis was performed on the outflow rate.Results A total of 2073 ILI samples were reported in Chaoyang district of Beijing in 2018.The sex ratio of patients was 43.37%males vs 56.63%females and the average age was 38.59±16.34 years old.Flu A/B single positive rate was 17.56%(364/2073);Flu A type accounted for 63.46%(231/364),of which,H1 N1 subtype 65.37%vs H3 N2 subtype 34.63%;Flu B type accounted for 36.26%(132/364),of which,B-Victoria20.45%vs B-Yamagata 79.55%;the mixed infection rate was 0.05%(1/2073).In the time distribution,the positive rate of flu A/B nucleic acid detection and the distribution of Flu A/B type were different in different months,and the difference was statistically significant(χ^2=522.021,P<0.05;χ^2=137.765,P<0.05).There was no significant difference in the positive rate of Flu A/B nucleic acid detection and Flu A/B type distribution between genders.There was no significant difference in the distribution of Flu A/B between different ages.There was no correlation between the ILI number and the positive detection rates of Flu A/B,Flu A and Flu B(rs=-0.242,rs=-0.102,rs=-0.156,respectively,P>0.05),and the detection rates of Flu A and Flu B showed positive correlation(rs=0.758,P<0.05).Conclusions The dominant strains of influenza epidemics in Chaoyang district of Beijing in 2018 were H1 N1 subtype and B-Yamagata,and the time distributions of B-Victoria and B-Yamagata were different.It is the first discovery that the detection rate of Flu A is positively correlated with detection of Flu B in this region,and the duration of the epidemic is related to the type of dominant strain.