A new influenza A virus infection in turkeys

In transmission experiments, the influenza A virus isolate turkey/ Ontario 7732/66 caused an acute disease in chickens and turkeys, but was apathogenic to ducks, geese and pigeons. After an incubation period from two to eight days, turkeys and chickens became rapidly depressed and died usually within the following four days. Other clinical signs were variable for the two gallinaceous species, such as exudative head swellings and gangrenous comb lesions in chickens, and diarrhea in turkeys. Infection by even minimal virus doses was fatal in turkeys, whereas chickens sometimes recovered from the disease or remained unaffected by the infection. Serial passage of the virus in chicken embryos accentuated this difference in species susceptibility still more. The infection spread easily by close contact among turkeys, but less among chickens.