Polar bears in Alaska face increasing threats from pathogens due to climate change

Polar bears in Alaska are facing a growing number of pathogens due to the warming climate, according to a study published Oct. 23 in PLOS ONE. The research indicated that pathogens previously unable to survive in Arctic conditions are now persisting in these environments. This is believed to be a result of the rapid changes caused by climate changes. The findings indicated a significant increase in polar bears’ exposure to viruses, bacteria and parasites, posing new threats to their already vulnerable populations.

Exposure to pathogens in the Chukchi Sea area

According to the studyblood samples collected from 232 polar bears in the Chukchi Sea between 2008 and 2017 were compared with samples from 115 bears examined between 1987 and 1994. This analysis revealed a clear increase in antibodies against pathogens such as Neospora caninum and bacteria that cause brucellosis and tularemia. Exposure to Toxoplasma gondii, a parasite linked to cats, increased from 2 percent to 14 percent, while antibodies against the canine distemper virus were also detected more frequently.

Wildlife biologist Dr. Karyn Rode of the US Geological Survey, who contributed to the research, explained in a statement to Science.org that global warming is allowing pathogens to infiltrate areas that were previously inhospitable to them. This phenomenon was especially evident in the Chukchi Sea, where polar bears had to adapt to reduced sea ice by spending longer periods on land, often coming into contact with human activities and waste.

Implications for the Arctic food chain

The study also examined chemical markers in the hair of polar bears to assess their diet, revealing a link between prey consumption and exposure to pathogens. The findings suggested that the entire Arctic food chain, including species such as ringed seals, could be affected.
According to sources, concerns have been raised about the potential risks to people who rely on an existing diet involving polar bears. Dr. Rode noted in another statement that further research is needed to understand how these pathogens may affect other species and human communities in the region.

Ecologist Dr. Andy Dobson of Princeton University also noted that while the study provides intriguing insights, additional data from across the population range are needed for conclusive results.