Analysis on influenza surveillance during epidemic period in Huairou District of Beijing from 2012-2013

[Objective]To understand the epidemic characteristics of influenza and the variant of influenza viruses during epidemic period in Huairou District of Beijing from 2012-2013,learn about the epidemic trends,and provide scientific basis for making the prevention and control strategies of influenza.[Methods]According to the criterion of China influenza surveillance program and Beijing influenza surveillance program,the epidemiological and pathogenic surveillance were conducted,and the results were collated and analyzed.[Results]From September 2012 to May 2013,2883 influenza like illness( ILI) cases were found in 717 582 outpatient cases,with the ratio of 0. 40%. 289 strains of influenza viruses were isolated from 1496 nasopharyngeal swab specimens,and the positive rate was 19. 32%. In the 289 isolates,170( 58. 82%) were influenza A( H1N1),and 119 were seasonal influenza A( H3N2). During the epidemic period in2012-2013,the isolation rate of viruses in December was the highest,and the predominant strain was influenza A( H1N1).[Conclusion]The epidemic situation of influenza in Huairou District has stayed relatively stable from 2012-2013,the sporadic cases are predominant,and there is not large-scale outbreak. The epidemiological data are not completely consistent with the viral isolation data,which indicates that the sensitivity and specificity of the influenza surveillance system should be further improved.