Polar bears face higher risk of disease in a warming Arctic

As the Arctic warms, polar bears face a rising risk of contracting viruses, micro organism and parasites that they have been much less more likely to encounter simply 30 years in the past, analysis has revealed.

In a research that has offered clues about how polar bear disease may very well be linked to ice loss, scientists examined blood samples from bears in the Chukchi Sea – between Alaska and Russia.

They analysed samples that had been gathered between 1987 and 1994, then collected and studied samples three many years later – between 2008 and 2017.

The researchers discovered that considerably extra of the current blood samples contained chemical indicators that bears had been contaminated with one of 5 viruses, micro organism or parasites.

It is tough to know, from blood samples, how the bears’ bodily well being was affected, however wildlife biologist Dr Karyn Rode from the US Geological Survey stated it confirmed that one thing was altering all through the entire Arctic ecosystem.

The researchers examined for six totally different pathogens in complete – viruses, micro organism or parasites which are primarily related to land-based animals however have been recorded earlier than in marine animals, together with species that polar bears hunt.

The research lined three many years, Dr Rode stated, “when there had been a substantial loss of sea ice and there’s been increased land use in [this population of polar bears]”.

“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, as disease-causing agents are collectively called, that 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 the virus that causes canine distemper.

“Bears in basic are fairly strong to disease,” explained Dr Rode. “It’s not sometimes been identified to have an effect on bear inhabitants, however I feel what it simply highlights is that issues [in the Arctic] are altering.”

• There are about 26,000 polar bears left in the world, with the majority in Canada. Populations are also found in the US, Russia, Greenland and Norway
• Polar bears are listed as vulnerable to extinction by the International Union for Conservation of Nature, with climate change a key factor in their decline
• Adult males can grow to be around 3m long and can weigh close to 600kg
• Polar bears can eat up to 45kg of blubber in one sitting
• These bears have a powerful sense of smell and can sniff out prey from up to 16km away
• They are strong swimmers and have been spotted up to 100km offshore. They can swim at speeds of around 10km per hour, due in part to their paws being slightly webbed

In the US, polar bears are classified as a threatened species; scientists say the biggest threat to their future is the continuing loss of sea ice habitat, which they depend on as a platform from which to pounce on their marine prey.

Previous research using collar cameras on bears has shown that, as they spend more of the year on land – when there is no available sea ice to hunt from – the bears are unable to find enough calories.

Dr Rode defined that polar bears are prime predators: “Our study suggested that they’re getting their exposure to some pathogens primarily through their prey species.

“So what we saw as changes in pathogen exposure for polar bears is indicative of changes that other species are also experiencing.”

The findings are printed in the scientific journal PLOS One.