Influenza viruses and paramyxoviruses in ducks in the Atlantic flyway, 1977-1983, including an H5N2 isolate related to the virulent chicken virus.

From 1977 to 1983, waterfowl migrating along the Atlantic flyway were annually monitored for orthomyxoviruses and paramyxoviruses in an area in central New York State. A total of 168 influenza isolates were obtained from 1,430 waterfowl. Twenty-four combinations of hemagglutinin and neuraminidase subtypes were detected, with as many as 12 found in a single year. One combination, an H5N2 isolate in 1982, was closely related to the virulent chicken virus that appeared in Pennsylvania in 1983. The prevalence of influenza varied greatly among the common waterfowl species: mallards 42%, black ducks 30%, blue-winged teal 11%, wood ducks 2%, and Canada geese 0%. A total of 89 paramyxoviruses were also from these waterfowl. In contrast to findings with influenza virus, the prevalence of paramyxoviruses did not differ significantly among the duck species. Serotype 1 (Newcastle disease virus) was predominant; three other serotypes were also identified. These findings indicated that ducks in the Atlantic flyway continually harbor influenza viruses and paramyxoviruses. The viruses may be a source of infection for other species.