Bird Migration and Influenza Active

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Mallard

The movement and transmission of avian influenza viruses in wild birds may differ by the migratory nature of each host species. USGS research examined migration patterns of mallards and northern pintails and found that mallards appear less likely to make migratory flights between Alaska and Asia.  Thus, mallards are less likely to transfer Asian origin viruses directly to North America via Alaska.  However, mallards may be acommon species to transmit avian influenza viruses once infected.

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Blue-winged Teal and H7 avian influenza

Many blue-winged teal winter in the Neotropics and breed in southern Canada.  Thus, the migratory routes of this species are a potential pathway for infectious agents to move between the Neotropics and North America.  For example, H7 subtype influenza viruses, which have important implications for domestic animal and human health, are seasonally abundant in blue-winged teal in spring. Although preliminary data suggest that these viruses do not contain South American types of viruses, it remains unclear if teal are transporting H7 viruses from Neotropic wintering areas (e.g. Columbia, Guatemala, and Mexico) into the United States and which locations may be at highest risk for the introduction of viruses. Using a combination of satellite telemetry and genomic sequencing of influenza viruses, this project investigates the intercontinental movement of hosts and viruses between the United States and the Neotropics. Results will provide information to optimize surveillance efforts for the introduction of avian pathogens into the southern United States and generate information that may be used to improve biosecurity of poultry production facilities in this region.

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Northern Pintail

Early on, the USGS identified the Northern Pintail as a model species to test the hypothesis that wild birds play a role in the dispersal of avian influenza viruses between continents.  Northern Pintails are one of the most common waterfowl species, breeding throughout high latitudes of Russian and Alaska and wintering throughout Asia and the lower-48 U.S. USGS research in the U.S. and Japan determined Northern Pintails are highly migratory, with satellite telemetry and band recovery data finding movement of pintails between East Asia and North America. Population genetic and banding data demonstrated that East Asia and Pacific U.S. populations are essentially one group that partially overlaps in northeastern Russia during the summer. In 2008, the USGS conducted genetic sequencing of avian influenza viruses isolated from pintails in Alaska and revealed a high frequency of Eurasian genes, suggesting viral gene flow between Asian and North America (See Koehler et al. 2008). Ongoing USGS Alaska Science Center research continues to provide support for maintaining Northern Pintails as a species of interest in surveillance efforts for foreign-origin pathogens into North America.

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Tundra Swan

Because Tundra Swans are potentially susceptible to highly pathogenic avian influenza virus, we sought to better understand the migration of Tundra Swans throughout North America. This project documents population differences in migration patterns and wintering distribution of Tundra Swans that breed across Alaska. A total of 50 Tundra Swans were fitted with satellite transmitters (PTT) at five different breeding areas in Alaska, including the southern and northern Alaska Peninsula, the Yukon-Kuskokwim Delta, drainages of Kotzebue Sound, and the Arctic Coastal Plain. An understanding of population-specific movement patterns of this widespread species will facilitate management of wildlife and domestic poultry populations and improve our understanding of the role of migratory birds in the redistribution of pathogens and contaminants. 

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Shorebirds

Shorebirds are a reservoir of avian influenza viruses and long-distance migrants, often crossing large distances in a single flight. As many as 20 shorebird species that visit North America in summer have migratory routes through Asia that overlap with past outbreak areas of highly pathogenic avian influenza. Thus, from a migratory perspective shorebirds constitute an important taxonomic group for avian influenza surveillance sampling in North America. However, few shorebirds have tested positive for avian influenza on the west coast of North America, in stark contrast to the Atlantic coast where prevalence is higher. USGS research demonstrated the shorebirds should not likely be considered a high priority for future avian influenza sampling on the west coast of the U.S. due to their low prevalence of viruses.

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Gulls

Gulls are a common reservoir species for avian influenza viruses and have been a high priority species to sample for pathogens because populations in western Alaska are thought to migrate to Asia for winter and thus have connections with outbreak areas of highly pathogenic avian influenza.  However, little is known about the migratory routes of gulls from northern and western Alaska.  Additionally, gulls are scavengers of dead animals and at landfills and may thus be a disease dispersal species, moving pathogens between wildlife and human environments.  The USGS Alaska Science Center is examining the prevalence and diversity of avian influenza in gulls each year through surveillance sampling.  Research is also examining how other marine birds may play a role in the maintenance and dispersal of avian influenza viruses.