Migratory Birds Spread Avian Influenza To Greenland’s Polar Bears

A Cornell University study has found evidence that polar bears in eastern Greenland are catching avian influenza from migratory birds that breed in the Arctic. The evidence is in blood from bears killed by Greenland Inuit subsistence hunters. The paper is in Emerging Infectious Diseases. Its first author, Kayla Buhler, is a postdoctoral researcher at Cornell's veterinary college and works at the University of Inland Norway.

The bears were hunted around Scoresby Sound, called Ittoqqortoormiit in the Eastern Greenlandic dialect. Co-authors at Aarhus University in Denmark, who collaborate regularly with the hunters, obtained 109 samples of heart blood from 2016 to 2025. Across the 10 years, nothing pointed to infection until 2024, when antibodies to influenza A were present in 21% of 14 bears. In 2025 the share was 43% of 14 bears. Further tests identified four bears with antibodies specific to highly pathogenic avian influenza (HPAI) viruses.

Buhler said the antibodies mark a past infection that the animal has cleared, not an active one, and that bears appear able to recover well. The bears were probably exposed in summer, and the hunts took place the next spring. The hunters, with long traditional knowledge of the bears, have not seen sick animals.

Bears that hunt on shrinking sea ice are pushed to look for food elsewhere, probably raising their exposure to the virus. Buhler said bears may be naive to pathogens on land, and that disease could matter for conservation as populations come under stress.

Birds from the East Atlantic and North American Atlantic flyways gather in large Arctic and Greenland colonies, where the virus can mix and spread. Bears can be infected by eating infected birds, eggs, seals or other animals, and could pass the virus on at carcass sites and at dumpsters near settlements.

In Svalbard, scientists said in 2026 that a young polar bear had died of HPAI once it ate an infected walrus. A 2025 Svalbard study detected H5N5 in Arctic foxes. Both studies described mutations suspected of making infection of mammals more likely. Dead birds in Greenland have carried HPAI strains, including H5N1 and H5N5.

Coverage: Eurasia Review