White-nose syndrome has killed millions of bats. The fungus that causes it is now in Alberta

A fungus that causes a disease that is nearly wiping out bat populations in Eastern Canada and the U.S. has made its first appearance in Alberta.

The fungus has been identified in several locations in the province after being found in Saskatchewan in 2021.

White-nose syndrome is a disease that starves bats to death by interrupting their winter hibernation, which wastes the energy they need to get through the winter.

"It looks like [the fungus is] spreading about 500 kilometres a year," said Cory Olson of the Wildlife Conservation Society, which conducted the research.

Society researchers traced the fungus by collecting bat droppings from underneath 800 bridges where the tiny mammals like to rest during the night.

"A lot of bridges have bats," said Olson. "About half of all the bridges we looked at had bat guano."

When analyzed, two samples from along the southern stretch of the Red Deer River came back positive for the fungus.

Other samples that showed likely infection came from along the Milk River in southern Alberta and as far north as the Battle River near Cold Lake.

The fungus affects an infested bat's skin. Olson compared it to athlete's foot.

"It eats away at their skin and they have to come out of hibernation to fight the infection — or it may be irritating and they can't hibernate when it's happening."

Bats' immune systems barely function when they're asleep, meaning they must wake up to fight the fungus. But during hibernation, bats may have to go without food for six months. Coming out of it costs them energy they need to make it through the winter.

"They simply starve to death before they can start feeding again," Olson said.

Because bats huddle closely together to survive the cold, the disease spreads quickly. It's also deadly.

In one cave in Eastern Canada, 98 per cent of bats died.

In eastern North America, where the disease has been present for almost 20 years, bat populations have shrunk by about 90 per cent.

Alberta has already declared endangered two species of the little brown bat, the province's most common bat, out of concern for the disease's eventual arrival.

"We're pretty likely to see similar declines in Alberta," Olson said. "It's not a lot of bats that can survive this disease."

'Bats are in trouble'

White-nose syndrome first appeared in North America in 2006 in New York state, probably through shipping. It's spread mostly bat-to-bat, although humans can play a role.

Bats play an important role in their various ecosystems. They are the major nighttime predator of flying insects, such as mosquitoes. A bat can eat its body weight in bugs during a single night's hunt.

They also feast on insects that damage human crops. Moths, for example, are prime bat food. Moths grow from caterpillars, a significant crop pest.

Olson said an American study concluded that bats provide pest control worth billions every year. He said the Canadian figures are likely in the "many millions" of dollars.

A small number of bats have shown a natural resistance to the fungus, which scientists are trying to understand. As well, researchers are experimenting with an antifungal agent that could be sprayed into bat caves.

Olson urges people to disturb bats as little as possible.

"Let them do their thing," he said. "Bats are in trouble."