Epidemiological characteristics of 771 influenza cases in Shenzhen port

Objective To analyze epidemiological characteristics of 771 influenza cases in Shenzhen port and to provide scientific evidence for the prevention and control of influenza.Methods We collected 771 influenza cases in Shenzhen port from May 2009 to February 2011 and analyze the data with descriptive epidemiology.Results All the 771 influenza-positive cases were passengers through Shenzhen port and mainly from mainland China and Hong Kong(91.6%);the ratio of male to female was 2.3:1;most of the cases were young adults under age of 40 years(73.2%).The clinical symptoms of the most cases were mild and most of the cases had fever of less than 39 ℃(79.8%).The three peaks of the influenza epidemic occurred in June to September 2009,July to October 2010,and January to February 2011.The prevalent type of the first peak was influenza H3;the second was influenza H3 and influenza A/H1N1;and the third peak was mainly influenza A/H1N1.Conclusion The influenza type in Shenzhen port changed from influenza type H3 to influenza type A/H1N1 and the most of the cases were young adults.