Epidemic of Influenza in Chongqing,2010

Objective To provide scientific evidence for developing the influenza prevention and control strategy in Chongqing by analyzing the epidemiological characteristics of influenza in Chongqing in 2010.Method Descriptive epidemiology analysis was conducted on the influenza monitoring results in Chongqing in 2010,which including the reported clinical diagnosed cases from medical institutions at all levels,influenza monitoring in sentinel hospitals,monitoring of outbreaks and network laboratory influenza-like illness pathogen monitoring.Result Totally 61 H1N1 influenza A cases were reported in Chongqing in 2010,with 1 death case,the incidence rate was 0.21/105,and case fatality rate was 1.61/105.The reported cases ranked 6 in the 26 categories of class B infectious diseases.For seasonal influenza,955 cases and 1 death case were reported,with the incidence rate was 3.369/105,and case fatality rate was 0.1047/105,and the reported cases ranked 5 in the 11 categories of class B infectious diseases.,The H1N1 A virus was the dominate strain in January 2010;and the seasonal B type was the dominate strain during February to June;which during July to September was seasonal A type;tha type A and type B were alternated during October to December.Patients were distributed in 34 districts/counties,cases reported in Fulig,Yuzhong and Yongchuan ranked top 3.The male to female ratio was 1.25∶1;most cases were student and children.There were 12 ILI(influenza-like illness) outbreaks reported around the city,totally 295 cases were reported.After sampling monitoring,10 outbreaks(83.3%) were identified as influenza epidemic;epidemic peaked in March to April and July to August;10 outbreaks occurred in schools,accounting for 83.33%;2 cases were nosocomial infection,accounting for 16.67%.Conclusion The epidemic of influenza was at a low level and main in sporadic in Chongqing Municipality in 2010.Schools are key sites of influenza outbreaks,the students are the most suffering population