In a recent study published in the journal Emerging Infectious Diseases , researchers in Alaska, United States of America (US) reported a natural infection of a highly pathogenic avian influenza (HPAI) A(H5N1) or bird flu virus in a young, free-ranging polar bear that was found dead in Alaska in 2023. They highlighted the significance of continued wildlife health surveillance by the community as well as by hunters in the Arctic. Dispatch: Highly Pathogenic Avian Influenza Virus A(H5N1) Clade 2.
3.4.4b Infection in Free-Ranging Polar Bear, Alaska, USA .
Image Credit: Alexey Seafarer / Shutterstock First detected in October 2020 in Europe, the HPAI A(H5N1) clade 2.3.4.
4b virus has since often infected various mammal species globally ever since. In North America, natural bird flu infections have been observed in several bear species, including Asiatic black bears, American black bears, grizzly bears, and Kodiak brown bears. Animals in captivity, including sloth bears, Asiatic black bears, and giant pandas, have been reported to contract other influenza A(H1N1) viruses.
Additionally, antibodies against H3 and H6 influenza subtypes suggest previous natural exposures to bird flu viruses. Notably, seroconversion has been noted in Barent Sea polar bears and Alaskan brown bears but not in the southern Beaufort Sea polar bears. Interestingly, genome analysis of Alaskan wildlife influenza viruses has both unreassorted and reassorted strains.
The HPAI virus genotype A3 was likely introduc.
