Norwegian researchers have confirmed the first known case of highly pathogenic avian influenza in a polar bear in Europe after a young male was found dead in northern Svalbard.
The one-year-old bear was discovered in Raudfjorden on Spitsbergen together with a dead walrus, both of which later tested positive for the H5N5 strain of bird flu, according to the Norwegian Veterinary Institute.
The animals were first spotted by tourist guides in mid-May. Shortly afterwards, two other polar bears in the area were observed limping with their hind legs, raising concerns about a neurological disease outbreak. Veterinarians from the Norwegian Veterinary Institute travelled to Svalbard to assist with field sampling alongside the Governor of Svalbard.
Laboratory analysis detected the virus in brain tissue from both animals, while tests for rabies came back negative.
The finding comes as scientists are documenting a wider spread of bird flu across Arctic wildlife. A recent preprint study by researchers from the Norwegian Veterinary Institute and partner institutions traced repeated introductions of highly pathogenic avian influenza viruses into Svalbard and Jan Mayen between 2022 and 2025. Scientists have increasingly detected highly pathogenic avian influenza in mammal species across Europe in recent years.
The first confirmed case on Svalbard was recorded in 2022, when H5N5 was identified in a glaucous gull near Longyearbyen. That same summer, researchers observed unusually high mortality among breeding great skuas on Hermansenøya. Since then, the virus has been detected in several seabird species, as well as walruses and Arctic foxes.
According to the study, multiple virus variants have reached the High Arctic through separate introductions rather than a single outbreak spreading through the region. The study suggests migratory seabirds moving between Europe, North America and the Arctic play a central role in introducing the virus into the High Arctic.
Bird flu has only previously been reported once in a polar bear, in Alaska in 2023.
Researchers say the recent detections highlight the need for continued monitoring of wildlife diseases in Arctic ecosystems, particularly as infections are increasingly being identified in mammals.
Léa Zinsli, PolarJournal