Abstract:

Objective To analyze the epidemic feature and regulation on influenza from 2011 to 2013,and provide scientific basis for influenza prevention. Methods The medical clinic, fever clinic, emergency department and children clinic were set up as monitor clinic, surveillance work were carried out in accordance with national influenza surveillance programme and the results were analyzed. Results The registration percentage of influenza like illness in outpatients (ILI%) in 2011, 2012, 2013 were 1.95%, 1.24% and 2.70%, respectively. The positive rate of nucleic acid of influenza virus in 832 ILI specimens was 13.82% and the constituent ratio of subtype B, seasonal A (H1N1), A (H3N2), A (H1N1) were 19.13%, 0.87%, 15.62% and 64.35%. The visiting peak of ILI occurred in winter and spring and correlated with the peak time of positive rate of nucleic acid (r＝0.457, P<0.001). The highest constituent ratio of age in ILI was 5~15 years old and there were significant differences in positive rate of nucleic acid among all age groups. Conclusion The epidemic strength of ILI was consistent with the activity trend of influenza virus and the prevention of influenza should be strengthened in winter-spring and summer. Moreover, more attention should be paid on sampling ratio in each age groups to reduce the surveillance differences caused by uneven distribution of sampling population.

Key words: Influenza, Surveillance, Etiology