SOUTHEAST POULTRY RESEARCH LABORATORY (SEPRL) UPDATE ON EXOTIC AND EMERGING POULTRY DISEASES

摘要

The recent outbreaks of H7N9 influenza in China has resulted in many human cases with a high fatality rate. Poultry have been suspected as the source of infection based on sequence analysis and virus isolations from live bird markets, but it's not clear which species of birds are most likely to be infected and shedding sufficient levels of virus to infect humans. Experimental studies with intranasal inoculation of chickens, Japanese quail, pigeons, pekin ducks, mallard ducks, muscovy ducks, and embden geese with A/Anhui/1/2012 virus resulted in infection but no clinical signs. Virus shedding in quail, chickens, and Muscovy ducks was much higher and prolonged than in the rest of the species. Quail effectively transmitted the virus to direct contactsbut pigeons and pekin ducks did not. In all species, virus was detected at much higher titers from oropharyngeal swabs than cloacal swabs. The high levels of viral replication in the upper respiratory tract are characteristic of poultry-adapted influenzaviruses.