Epidemiological characteristics of influenza-like illness outbreak in Foshan City,2004-2011

Objective To understand the epidemiologic situation of influenza-like illness(ILI) and influenza outbreak,and the variation of influenza virus,analyze the epidemiologic characteristics and influence factors,to take proper action for prevention and control of influenza.Methods Epidemic data of ILI and outbreaks between 2004 and 2011 were analyzed.Binomial logistic classification regression was used to analyze the influence factors of outbreaks;Pearson correlation was used to analyze the relationship between the reporting time of the first ILI case and the duration of whole event.Results A total of 66 outbreaks of ILI and influenza were reported in Foshan City from 2004 to 2011.The peak of influenza outbreaks was from March to June(57.58%,38/66).Schools and kindergartens reported 61 influenza outbreaks(92.42%).Influenza A(H3N2)and influenza A(H1N1),and influenza B were the main virus types and caused 13,14 and 19 outbreaks,respectively.Logistic regression analysis showed whether reporting the outbreaks through the Student health care information systems were statistically significant relating with the outbreak of rate levels(OR=0.256) and duration(OR=0.281)(P0.05).Reporting via Student health care information was a protective factor in the outbreak.The duration of the occurrence of the first ILI case to the reporting time was positively related with the duration of whole event(Pearson correlation coefficient=0.576,P0.01).Conclusion The peaks of influenza outbreaks were mainly from March to June in Foshan City.The schools and childcare facilities are high-risk areas for influenza outbreak.To enhance disease surveillance and establish the school childcare facilities reporting system and platform,actively carry out health education,and promote influenza vaccination are conducive to contain the outbreaks timely.