Disease risk for polar bears increased by climate change
With the Arctic warming, polar bears are facing an increased disease risk compared to three decades ago, new research has found. A study published in the journal PLOS One, offered clues about how polar bear disease could be linked to a loss of ice loss.
The team analysed samples gathered between 1987 and 1994 and collected and studied samples dated between 2008 and 2017, three decades later. They found that more of the blood samples contained chemical signals that polar bears were infected with one of five viruses, bacteria, or parasites, suggesting an increased disease risk.
The blood samples are not enough to show how the animals’ physical health was affected. But it showed that something had been changing throughout the entire Arctic ecosystem, according to Dr Karyn Rode from the US Geological Survey.
A total of six different pathogens were tested for by the research team. These included viruses, bacteria, and parasites that are associated with land-based animals but have also been recorded in marine animals such as the kind hunted by polar bears.
The study covered three decades “when there had been a substantial loss of sea ice and there’s been increased land use in [this population of polar bears],” said Dr Rode. “So we wanted to know if exposure had changed – particularly for some of these pathogens that we think are primarily land-oriented.”
The five pathogens have become more common in polar bears are two parasites that cause toxoplasmosis and neosporosis, two types of bacteria that cause rabbit fever and brucellosis, and a virus that causes canine distemper.
“Bears in general are pretty robust to disease,” explained Dr Rode. “It’s not typically been known to affect bear population, but I think what it just highlights is that things [in the Arctic] are changing.”
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