Is the occurrence of avian influenza virus in Charadriiformes species and location dependent?

Birds in the order Charadriiformes were sampled at multiple sites in the eastern half of the continental USA, as well as at Argentina, Chile, and Bermuda, during 1999-2005, and tested for avian influenza virus (AIV). Of more than 9,400 birds sampled, AIV virus was isolated from 290 birds. Although Ruddy Turnstones (Arenaria interpres) comprised just 25% of birds sampled, they accounted for 87% of isolates. Only eight AIV isolations were made from birds at four locations outside of the Delaware Bay, USA, region; six of these were from gulls (Laridae). At Delaware Bay, AIV isolations were predominated by hemagglutinin (HA) subtype H10, but subtype diversity varied each year. These results suggest that AIV infection among shorebirds (Scolopacidae) may be localized, species specific, and highly variable in relation to AIV subtype diversity.