Surveillance for influenza in Fuxin, Liaoning,2010-2014

Objective To understand the epidemiological and etiological characteristics of influenza in Fuxin, Liaoning province, from 2010 to 2014,predict the short term trend of influenza like illness (ILI) and provide evidence for the prevention and control of influenza. Method Descriptive epidemiological analysis was conducted on the annual surveillance data of ILI and pathogens collected from sentinel hospitals in Fuxin from 2010 to 2014. ARIMA (1, 0, 0) model was established by using time series data of ILI proportion in the 164 weeks. Results The incidence peak of ILI occurred during December-February during this period, and age specific ILI incidence varied. A total of 116 strains of influenza viruses were isolated, seasonal influenza A (H3N2) virus was predominant during this period. The viruses were mainly isolated during December-February. Weekly reported ILI case number was positively correlated with positive detection rate of influenza viruses(rs=0.423, P0.05). The residual difference by ARIMA (1, 0, 0) model had no statistical significance (Ljung-Box Q=19.948,P=0.277), indicating the residual was white noise. The average of the relative error between actual value and predicted value was 0.804%. Conclusion The annual incidence peak of influenza was during winter-spring in Fuxin. Age group 0-4 years was at high risk, followed by age group 14 years. The predominant pathogens varied with year. The ILI incidence peak was closely correlated with the positive detection of influenza viruses. ARIMA model can well simulate the incidence trend of influenza-like illness in Fuxin, which is suitable for the short-term prediction.