Abstract
A hemagglutinating agent was isolated from the respiratory organs of budgerigars suffering from diarrhea and malnutrition. This agent, possessing neuraminidase activity, was identified as influenza A virus by the double immunodiffusion test.
The results of hemagglutination and neuraminidase-inhibition tests with monospecific antisera to the isolated surface antigens showed that the isolates possessed Hav4 hemagglutinin and Nav 1 neuraminidase subunits both of which were closely related to the corresponding antigens of A/duck/Czech/56 (Hav4 Nav 1).
