Surveillance of influenza in Jiangxi, 2009-2011

Objective To learn about the epidemiological characteristics of influenza in Jiangxi,understand the circulation of subtype influenza viruses and provide scientific evidence for the prevention and control of influenza. Methods The sentinel surveillance data of influenza like illness (ILI) in Jiangxi from 2009 to 2011 were collected to conduct analysis. Results From September 2009 to September 2011, a total of 167 346 ILI cases were reported, which accounted for 3.74% of the total outpatient visit. Two incidence peaks occurred in spring and autumn;Totally 12 778 samples collected from ILI cases were tested in influenza network laboratories, the positive rate was 25.76%. Among the positive samples, influenza A (H1N1) pdm 09 (pH1N1) viruses accounted for 53.24%,influenza A viruses unspecified accounted for 23.46%,influenza B viruses accounted for 21.45%, influenza A (H3) virus accounted for 1.82%, influenza A (H1) viruses accounted for 0.24% and the mixed accounted for 0.09%. Conclusion The seasonality of influenza viruses circulation was obvious in Jiangxi during this period. During the incidence peak periods, different predominant subtype strains were detected. The occasional active circulation of (pH1N1) virus at the late phase would have slightly influenced the proportions of the predominant strains of seasonal influenza viruses, but influenza B viruses were detected all the year round.