Surveillance of influenza in Changzhou city in Jiangsu province, 2009 - 2010

Objective To understand the epidemiological characteristics of influenza in Changzhou and provide evidence for the prevention and control of influenza. Methods The analysis was conducted on the surveillance data and laboratory detection data of influenza like illness (ILI) cases from June 2009 to December 2010 in Changzhou. Results The surveillance data indicated that the number of ILI cases declined obviously and remained at low level after the incidence peak of 2009 pandemic influenza A (H1N1). The incidence peak of influenza was during late autumn-early winter or during winter in Changzhou. Influenza A viruses and influenza B viruses circulated alternately. ILI mainly affected children and adolescents. Conclusion It is necessary to strengthen the surveillance of influenza in winter and pay close attention to protect susceptible population of children and adolescents.