Analysis on Influenza Surveillance in Longgang District of Shenzhen

Objective To investigate the epidemic regularity of influenza virus in Longgang District of Shenzhen from April 2009 to May 2010,and to provide the evidence for effective control of influenza.Methods The situation of influenza epidemic in Longgang District was analyzed according to the surveillance of epidemiology,serology and etiology.Results A total of 43,249 influenza-like illness(ILI) cases were collected from April 2009 to May 2010 in Longgang District,which accounted for 8.42% of the all OPD cases.ILI cases distributed throughout the year,with the peak in June and July.ILI cases were mainly found in the age groups of 0~year and 5~years,which accounted for 79.4%.A total of 520 ILI nasopharyngeal swabs were collected,91 strains of influenza viruses were isolated,which included 19 strains of influenza virus(H1N1),7 strains of H1N1 virus,14 stains of H3N2 virus and 51 strains of influenza B virus.Primary and secondary schools were the major spots of the outbreaks.Conclusions ILI occurred throughout the year in Longgang District of Shenzhen City and peaked in summer and winter.The predominant virus types were seasonal H1N1 and new influenza(H1N1) according to nucleic acid(Victoria series) and influenza A(H1N1).Influenza surveillance is important to prevent influenza epidemic.