Surveillance for avian influenza A(H7N9)virus in outer environment in Yongjia 325102, Zhejiang

Objective To understand the distribution of avian influenza A(H7N9)virus in outer environment in Yongjia, Zhejiang province and provide evidence for the prevention and control of human infection with H7N9 virus. Methods The samples of chicken or duck throat secreta, anus fecess, blood, wing smear, egg smear, cage smear, egg trough smear and water were collected from poultry farms, farm produce markets, slaughter houses and rural restaurants to detect H7N9 virus by using nucleic acid detection reagent kit produced by Shanghai Zj Bio-Tech Co. Ltd. Excel software was used to analyze the results statistically. Results During the 8 months surveillance, H7N9 viruses were detected in 4 months(50%), and the viruses were detected in 7 of 68 surveillance sites(10.29%). The surveillance sites were far from each other. A total of 1670 samples were detected, including 1138 chicken related samples(23 were positive, accounting for 2.02%)and 532 duck related samples(none was positive). H7N9 viruses were detected in 3 of 15 poultry farms(20%), among the 623 chicken samples, 14 were positive(2.25%). And H7N9 viruses were detected in 4 of 38 farm produce markets(10.53%), among the 355 chicken samples, 9 were positive(2.54%). All the 26 persons with close contacts with H7N9 positive alive poultry were negative in testing of their throat swabs and no human infections with H7N9 virus were detected. Conclusion H7N9 virus circulated in outer environment. The probability of circulation of H7N9 virus in chickens was higher than that in ducks, indicating that the virus is prone to spread in chickens. The pathogenicity of H7N9 is low to humans and the transmissibility is weak.