Serological study of human infection with avian influenza A (H9N2) virus in population with occupational exposure in China

Objective To evaluate the risk of human infection with avian influenza A (H9N2) virus in population with occupational exposure in China. Methods A total of 13,715 serum samples were collected from people with occupational exposures in 22 provinces of China. Hemagglutination inhibition (HI) test was conducted to detect these serum samples and micro neutralization (MN) assay was used to confirm the results by using G9 lineage virus A/Chicken/AK4/Anhui/2011 as antigen. Results Among the serum samples detected, 63 were H9N2 virus positive (0.41%). Positive serum samples were detected in all the people with occupational exposure to poultry. The seroprevalence in workers in live poultry market was significantly higher than that in other groups. Conclusion Exposure to live poultry was the major risk factor for human infection with avian influenza virus. It is necessary to strengthen the surveillance for H9N2 virus infection in population with occupational exposure in China, which will benefit the effective prevention and control of human infection with avian influenza virus.