Epidemic characteristics of human infection with avian influenza A (H7N9) virus and influence of closure of live poultry markets on the epidemic in Zhejiang

Objective To understand the influence of closure of live poultry markets on epidemic of human infection with avian influenza A (H7N9) virus in Zhejiang province and provide evidence for the prevention and control of human infection with H7N9 virus. Methods Descriptive epidemiological analysis was conducted on the incidence data of human infection with H7N9 virus in Zhejiang in 2014, and the infection sources of H7N9 virus after the closure of live poultry markets in Zhejiang were traced back. Results A total of 87 cases of human infection with H7N9 virus were reported in Zhejiang in 2014. The incidence peak occurred in January, the average age of the cases was 56.1 years. The cases were distributed in 39 counties, but the cases in 17 counties with serious epidemic accounted for 74.7% of the total. Up to 66.7% of the cases occurred in rural area. Twenty six cases were reported after the closure of live poultry markets in 3 cities with high infection rates (Hangzhou, Shaoxing and Ningbo), among these cases, 18 had exposures to live poultry before the market closure, 7 had exposures outside live poultry markets and 1 had no exposure in live poultry market. Conclusion It is essential to identify the areas with serious epidemic timely and close live poultry markets for the effective control of human H7N9 virus infection epidemic.