Analysis on the sentinel surveillance of influenza in Ba′nan district of Chongqing in 2009-2011

Objective:To analyze the sentinel surveillance results of influenza in Ba′nan district of Chongqing during 2009-2011,so as to fully grasp the epidemic features of influenza and the advantage strain change to explore the prevalent regularity.Methods: Based on "China influenza monitoring information system",the data of influenza-like illness,etiology material were involved in this analysis.Excel2003 and SPSS17.0 software were used for data collection and processing,and statistical description,chi-square test method were also employed for statistical analysis.Results: The percentages of ILI in 2009,2010 and 2011 were 4.07%,4.91% and 4.31%.Influenza-like illness mainly concentrated on 0～ years old,5～ years old group,accounting for 69.54% of the total.The flu virus separation rate was 24.22%,among which major epidemic strains in 2009 was the type new A(H1),in 2010 was the type B,the type new H1 and type B were both advantage strains in 2011.The virus separation rate was higher in age groups of 5～ years old,15～ years old and 25～ years old.Conclusion: It is necessary to strengthen influenza monitoring on elder people in summer and pay attention to the situation of influenza B to prevent the outbreak of influenza B.