Ecological aspects of influenza A virus circulation in wild birds of the Western Palearctic

摘要

The role of wild animals in the ecology of influenza is considered to be very important. Many researchers consider the natural reservoirs of the influenza A virus to be wild birds, principally those belonging to the Order Anseriformes. Many influenza viruses, showing all the possible haemagglutinin (HA) and neuraminidase (NA) antigenic combinations, have been isolated from birds belonging to 88 species, 22 families and 12 orders all belonging to the Class Aves: these various free-living species can assume different epidemiological roles in the natural influenza cycle (Stallknecht and Shane, 1988). Influenza A viruses have also been isolated, although infrequently, from wild mammals such as Mustelidae (Mustela spp.) and marine mammals (Pinnipeda, Cetacea) (Webster et al., 1992).