Movements of Birds and Avian Influenza from Asia into Alaska

Abstract

Despite involvement of large numbers of birds, the delivery rate of Asian-origin viruses to North America through Alaska is apparently low.

Influenza A Virus Infections in Land Birds, People’s Republic of China

“…An important part of the argument centers on the question of the occurrence of the virus in wild birds without obvious illness, which can be diffi cult to interpret given the low prevalence of infl uenza. For instance, a recent study based on sampling >13,000 migratory birds in China detected the subtype H5N1 strain of infl uenza virus only 8 times (12), and similar results have been obtained elsewhere (2). Our study, although not successful in characterizing infl uenza viruses to specifi c strains, nonetheless shows that infl uenza A virus infection occurs in more bird species than previously assumed and that infl uenza A infections can be found in birds that behave normally and show no sign of illness.…”

Dissemination of Multidrug-Resistant Bacteria into the Arctic

“…Although many of these species are largely confi ned to one side of the Bering Strait, other species pass through both continents during migration or occasionally wander across the strait (11). Moreover, bird species that spend the winter in up to 6 different continents can be found in this area (11). Thus, migratory birds that have acquired drug-resistant bacteria during wintering or stops at lower latitudes before migrating to the Arctic provide a potential explanation for introduction of drug resistance into this region.…”

Cross-Seasonal Patterns of Avian Influenza Virus in Breeding and Wintering Migratory Birds: A Flyway Perspective

“…Within this flyway the dispersal of AIV has potential public health risks. Of the four migratory flyways that encompass North America, the Pacific Flyway has the greatest potential for the introduction of the highly pathogenic AIV of the lethal H5N1 subtype by wild birds due to overlap with birds from Asia where outbreaks occur frequently (Winker et al 2007, Koehler et al 2008, Pearce et al 2009). Although trans-hemispheric gene flow appears to be relatively rare, invasion of a Eurasian subtype hemagglutinin gene has been documented within the Pacific Flyway.…”