Analysis on Influenza Surveillance in Futian District of Shenzhen City during 2007-2009

[Objective]To understand the dynamic epidemiologic characteristics of influenza and variation of influenza virus strains in Futian District,and provide scientific basis for the prevention and treatment of influenza.[Methods]Influenza-like illness(ILI) data of monitoring hospitals were weekly analyzed and the nasopharyngeal swab samples of ILI were collected.MDCK cells were used for influenza virus isolation.Hemagglutination inhibition experiments were applied to identify influenza virus type.[Results]From 2007 to 2009,a total of 32 961 cases of ILI were monitored,accounting for 5.61% of total monitoring out-patients;363 influenza strains were isolated,the virus isolation rate was 34.41%.The annual trend of ILI% was consistent with the trend of virus isolation rate;97 epidemic outbreaks occurred mainly in schools and nurseries.[Conclusion]The epidemiologic peak of influenza is from June to August in Futian District,the influenza virus subtypes alternate,the virus strain type usually changed in June.The ILI% and the isolation rate and the epidemic outbreaks increasing is mainly due to influenza pandemic of H1N1 in 2009.