Surveillance of influenza in Zhejiang, 2008-2012

Objective understand the epidemiological characteristics of influenza in Zhejiang province and provide evidence for the prevention and control of influenza. Methods Descriptive epidemiological analysis was conducted on the surveillance data of influenza 1ike illness and influenza outbreak information in Zhejiang from 2008 to 2012. Results The average proportion of ILI cases in total outpatients was 4.00% in sentinel hospitals during this period. The ILI cases were mainly children aged15 years. The annual peak of positive laboratory detection was consistent with that of ILI cases. The outbreak mainly occurred in schools and child care settings. Conclusion The seasonality of influenza was obvious in Zhejiang. The change on epidemiological characteristics of influenza had been observed since the epidemic of influenza A (H1N1) pdm 09 in 2009.