Analysis of the surveillance for influenza outbreak in Shiyan City(2004-2008)

Objective To analyze the etiological and epidemiological characteristics of influenza outbreak from April 2004 to March 2009 in Shiyan city,so as to provide evidence for its prevention and control.Methods To analyze the investigation reports and laboratory data of influenza outbreak during this period.Results 31 influenza outbreaks and 1 151 cases were reported during this period,involving urban area and 5 counties,including 26 middle and primary schools and 5 secondary schools,most cases were from January to May,and from August to September.The separated influenza virus were H3N2、H1N1 and B(Victoria).Conclusions During this five-year period,most outbreaks occurred in schools,the peak of influenza epidemic was in winter,spring and summer in Shiyan.It indicates that surveillance should be strengthened,and,in particular,vaccination rate for the priority population before the peak should be enhanced.