This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Migrating birds that breed in the Arctic are spreading avian influenza to polar bears in eastern Greenland, according to a new study that found evidence of infections in bear blood samples acquired from Greenland Inuit subsistence hunters. The results suggest that such emerging viruses may pose risks to Arctic mammals.
The Arctic is warming at faster rates than much of the rest of the planet—in the western Arctic, four times the global rate. As a result, threatened polar bears that hunt on dwindling sea ice are being forced to search for food elsewhere, which has likely increased their odds of exposure to highly pathogenic avian influenza (HPAI). "With climate change, we know that the bears are changing their diets, and they're likely becoming exposed to many new pathogens on land that they could be naive to, because they come from a life highly adapted to the ice," said Kayla Buhler, a Cornell K.
Lisa Yang Center for Wildlife Health postdoctoral fellow in the College of Veterinary Medicine. Buhler is first author of the study, published Oct. 13 in Emerging Infectious Diseases. A wide range of global bird species migrate northward via East Atlantic and North American Atlantic flyways to breed in the Arctic and Greenland.
There, they congregate in large colonies, creating a perfect hot spot for viral mixing and transmission. These birds include many species of shorebirds and waterfowl that are the main reservoirs of HPAI. "It's important for us to monitor what new pathogens are becoming established in polar bears because we don't know how they'll be affected," said Buhler, who is also a researcher at the University of Inland Norway.
"As populations become more and more stressed, diseases and pathogens could play a critical role in conservation efforts." The high exposure in polar bears creates additional questions about whether the HPAI viruses in Greenland contain mutations that make them more infectious to mammals and if HPAI could be transmitted from one polar bear to another. Samples from polar bears in this study were collected during the subsistence hunts that occur around Scoresby Sound, also known as Ittoqqortoormiit in the Eastern Greenlandic dialect. As ice recedes, polar bears are moving to land to search for new ways to meet their nutritional needs.
"On Svalbard, Norway, we see that polar bears are now taking down reindeer, which is something never seen before in the past. There and in many other parts of the Arctic, they are starting to raid bird colonies," Buhler said. Disease can spread when bears eat live and dead birds and eggs, or seals or other animals infected with HPAI.
Extract — continue reading at the source.
