2012-2013年度上海市虹口区流感监测及流行特征分析

Surveillance of influenza in Hongkou district of Shanghai,2012-2013

目的了解2012-2013年度上海市虹口区流行性感冒（流感）的流行特征,为预防控制流感提供科学依据。方法对2012-2013年度监测流感样病例（influenza-like illness,ILI）监测资料、病原学监测结果及聚集性疫情信息进行统计分析。结果上海市虹口区2012-2013年度流感监测哨点医院ILI就诊百分比（ILI%）平均为0.46%,病例以25~59岁青壮年为主,期间共监测1 481份ILI的咽拭子样本,其中流感病毒核酸检测阳性273份,阳性率18.43%;分离流感病毒131株,其中H3N2性69株（52.67%）,B型51株（38.93%,均为Victoria系）,H1N1型11株[8.40%,均为A（H1N1）pdm09]。2012年ILI%与流感病毒PCR检测阳性率之间存在一定相关性（r=0.51,P〈0.01）,2013年两者无相关性（r=-0.20,P〉0.05）;2012-2013年共报告流感聚集性疫情3起,均发生在学校和幼托机构。结论 2012-2013年上海市虹口区流感活动强度逐渐降低,不同亚型流感病毒交替流行。ILI%难以准确的反应流感病毒在人群中的流行情况,尚须辅助以其他手段;加强流感监测,有效控制流感疫情。

Objective To understand the epidemiological characteristics of influenza in Hongkou district of Shanghai,and to provide evidence for disease prevention and control. Methods Data of cases with influenzalike illness（ILI）were collected and analyzed in Hongkou district of Shanghai from 2012 to 2013regarding the disease etiology and clustering features. Results The average percentage of cases with ILI was 0.46 in influenza sentinel surveillance hospitals during the study period,and majority of cases were young adults.A total of1481 nasopharyngeal swab samples from ILI patients were collected and tested,from which 273 specimens were RNA positive with positive rate of 18.43%.131 strains of influenza virus were isolated with 52.67%of influenza A（H3N2）,38.93%of influenza B（Victoria）,8.40%of influenza A（H1N1pdm09）.There was a positive correlation between ILI%and positive rate of influenza by PT-PCR in 2012（r=0.51,P〈0.01）,but not in 2013（r=-0.20,P〉0.05）.Three clustering of influenza cases were reported from 2012-2013,and all occurred in schools and children care centers. Conclusions The activity of influenza virus in Hongkou district from 2012 to 2013decreases annually,with different virus sub-types prevailing alternatively.It is hard to reflect the real endemic situation only by ILI%.Therefore,the current surveillance system needs to be improved in order to effectively control influenza.