Analysis of surveillance of highly pathogenic avian influenza in occupational exposure crowd and environment in Baiyin City

Objective To learn the infection of avian influenza in occupational exposure crowd and pollution situation of avian influenza virus H5, H7, and H9 subtypes in external environment, to provide a scientific basis for avian influenza prevention. Methods Regions with developed poultry industry were selected as the monitoring sites, and environmental samples and serological samples of occupationally exposed populations were collected and detected. The serum samples were detected for H5, H7 avian influenza antibodies with horse blood serum samples inhibition(HI) and the external environment samples were detected with avian flu virus nucleic acid method. Results Out of the 290 external environment specimens,49 specimens were positive of avian influenza viral nucleic acid with positive rate of 16.90%, including 48 specimens of H9 positive and 1 specimen of H7 probable positive. There was statistical difference(P0.05) in positive rate between various time(χ2=21.655) and various samples(χ2=16.934), and no statistical difference in positive rate among monitoring sites(χ2=1.203, P0.05). H5 and H7 antibodies of 200 sera of occupationally exposed crowd were negative. Conclusions There is no case subclinically infected with avian influenza in the exposure crowds in Baiyin City, but avian influenza virus H9 subtype is widespread in external environment. Avian influenza virus exists in transshipment center such as poultry sales market and poultry farms. Quarantine system for poultry trading market should be improved and epidemic prevention in poultry farms should be strengthened.