珠海市2006-2008年流感症状监测分析及预测

目的 了解广东省珠海市2006-2008年流感流行趋势及其病毒株变化特点,预测2009年流行趋势,为本地区防控流感提供科学依据。方法 收集2006-2008年珠海市流感监测哨点流感样病例(ILI)监测和暴发疫情监测资料信息,医院门诊、暴发疫情的流感病毒病原学监测资料,进行综合分析。采用季节性自回归移动平均(ARIMA)构建模型预测2009年ILI的趋势。结果 2006-2008年珠海市流感流行大致呈3-4月和6-7月的双峰型,平均ILI%为4.1%;门诊报告ILI中<5岁儿童为主,占50.3%,构成比逐年上升。哨点医院流感病毒分离阳性率为10.0%,2006年流感季节类型为A(H1N1)型和B型混合型,2007年为A(H3N2)型占优势,2008年为A(H1N1)型和A(H3N2)型混合型。暴发疫情主要发生在3-6月,流行病毒株与医院哨点监测基本一致。结论 珠海市流感流行呈现春夏季双峰型,ILI的高峰较流感病毒早4周左右;H3型、H1型、B型流感病毒交替成为年分离优势株。预测2009年季节性流感流行趋势平稳。

Syndromic surveillance and prediction of Influenza in Zhuhai, 2006-2008

Objective To analyze and predict the trend of prevalence and predominant strains of influenza viruses and provide scientific basis for the prevention and control of influenza in Zhuhai. Methods Epidemiological surveillance was performed by 28 sentinels. Influenza-like illness(ILl) cases of out-patient were reported weekly. Influenza viruses were iso-lated from nasopharynx specimens collected by doctors from ILI cases in sentinel hospitals. The information of outbreaks collected through influenza surveillance network and daily surveillance was used to predict the tendency of ILI% in 2009 with autoregressive integrated moving average model (ARIMA). Results Influenza virus prevalence exhibited seasonal bi-modal pattern, with one peak in March to April and another in Jun to July. The weekly percentage of out-patient visitors for ILI (ILI%) ranged from 1.5 % to 10. 1% during 2006-2008, and the average was 4. 1%. Children under five years of age were the main part (50. 3%) of ILI. There were 3,216 specimens tested for influenza viruses and 321 (10. 0%) were posi-tive. Of the positive specimens,230 (71.7%) were influenza A virus,and 91 (28. 3%) were influenza B virus. The influ-enza A (H1N1) virus and influenza A (H3N2) virus circulated simultaneously in 2006,influenza A(H3N2) virus predom-inated circulation in 2007, and influenza A (H1N1) viruses and influenza A (H3N2) virus circulated simultaneously in 2008. Outbreaks of influenza oceured mostly in March to June. Conclusion Influenza prevalence showed two peaks distrib-uted in spring and early summer in Zhuhal. ILl preeedeed the oscillations of laboratory surveillance by about four weeks. The construction of subtype strains usually take turns to be the annually outstanding subtype. The curve predicts that the epi-demic tendency of seasonal influenza in 2009 will be stable.