Etiological analysis of influenza surveillance data in Fangshan District of Beijing from 2014 to 2015

Abstract

Objective To analyze the results on etiological surveillance of influenza in Fangshan District from 2014 to 2015, so as to forecast the prevalence trend of influenza. Methods Throat swab samples were collected from influenza-like cases and were analyzed by real-time RT-PCR method and virus isolation. Results A total of 1339 throat swab samples from influenza-like cases were collected. Viral nucleic acid was positive in 215 samples (positive detection rate, 16.06%), including 32 samples of influenza A (H1N1) virus, 107 samples of influenza A (H3N2) virus, 76 samples of influenza B virus. One hundred and forty-eight strains of influenza viruses were isolated by cell culturing (positive separation rate, 11.05%). The positive rates of influenza in periods of the 2nd to the 6th week and the 48th to the 52nd week of the year were higher. The main influenza virus subtypes were influenza A (H1N1) virus and influenza B virus in period of the 2nd to the 6th weeks, and influenza A (H3N2) virus in the 48th to the 52nd weeks. Conclusions The peak time of influenza in Fangshan District was the periods of the 2nd to the 6th weeks and the 48th to the 52nd weeks of the year from 2014 to 2015. In the first half of the year, the predominant strains were influenza A (H1N1) virus and influenza B virus. In the second half of the year, only influenza A (H3N2) virus was found. No significant difference was found in each subtype of influenza virus in different genders (P>0.05). Key words: Influenza virus; Surveillance; Aetiology