In a federal research laboratory in Wisconsin, scientists are analyzing DNA from the fungus that killed a little brown bat in Washington last month.
The bat was the Northwest’s first confirmed case of deadly white-nose syndrome, and the genetic work will offer clues about how the fungus arrived in Washington.
Since it was first discovered in eastern New York in 2007, the fungus causing white-nose syndrome has spread westward, attacking colonies of hibernating bats and killing more than 6 million in the U.S. and Canada. But its detection in the central Cascades – about 1,300 miles from infected populations in eastern Nebraska and northern Minnesota – caught bat researchers by surprise.
“It showing up in Washington shocked me,” said Rita Dixon, Idaho’s state wildlife action plan coordinator. “For it to skip over to the West Coast wasn’t what we expected. We thought it would take more time to get here.”
Hikers found the sick bat March 11 near North Bend, Washington. The bat, a western subspecies of little brown bat, died two days later.
“This was a local bat, not one that flew in from outside the region,” said Joe Buchanan, a Washington Department of Fish and Wildlife scientist. “We’re treating this as a very serious turn of events.”
Scientists from the National Wildlife Health Center in Madison, Wisconsin, expect to have preliminary results from the DNA work in about two months. Their work will help trace the origin of the fungus found on the Washington bat.
“There are two options: Did it come from North America, or did it come from Eurasia?” said David Blehert, a microbiologist and branch chief at the National Wildlife Health Center.
If the DNA is closely related to strains from eastern North America, the fungus could have spread from bat to bat, he said. It also could have reached the Northwest through human activity.
But if the DNA is related to strains of the fungus from Europe or Asia, people were definitely involved in the transmission.
“We know there are no bats that naturally migrate between these two continents,” Blehert said. “The transmission could be a caver who went to an infected site in Europe and transferred a dirt clod with infected spores to a site occupied by bats in Washington. … It could be that somebody packaged bat guano from an infected site and sold it for fertilizer.”
With the arrival of white-nose syndrome in the Northwest, state and federal agencies are developing plans to increase bat monitoring and survey work.
Unlike eastern bats, which congregate in large numbers in caves and mines, western bats tend to hibernate in small groups in rock crevices and other hard-to-find spots. That makes western bats more challenging to track and study, Buchanan said.
The sick bat found near North Bend was about 20 miles from the nearest known hibernation spot for its species.
“We’d like to learn more about where these bats are hibernating in the state,” he said.
Researchers also are interested in how white-nose syndrome spreads among smaller clusters of bats.
“Our bats behave differently than eastern bats,” Buchanan said. “We suspect that might be significant in some way, but we don’t know that yet.”
White-nose syndrome gets its name from the white fuzz that grows on infected bats’ muzzles, ears and their wing and tail membranes. The fungus attacks bats during hibernation, when their body temperatures are low and their immune systems are less active.
“That’s why the fungus is able to go in and have such devastating effects on the populations,” said Dixon, the Idaho wildlife action plan coordinator. “A lot of fungus is superficial on the skin. This actually invades on the cellular level. It goes through the outer surface of the wing membrane.”
The sick bat near North Bend had severe wing damage.
“When bats can’t fly, they can’t feed,” Dixon said.
The fungus also causes physiologic imbalances that can lead to disturbed hibernation, depleted fat reserves and dehydration. Infected bats usually die, though some survive if they only get mild infections toward the end of hibernation.
Rebuilding populations that have been decimated by white-nose syndrome takes time. Bats can live 30 years, but females produce only one or two pups per year.
Washington is home to 15 bat species; Idaho has 14. White-nose syndrome is known to affect seven North American bat species.
“They’re remarkable animals,” Dixon said. “Bats eat insects and they feed primarily on the insects we consider pests. If we didn’t have bats, we’d be in a world of hurt. ”
In Idaho, bats provide a $313 million annual benefit to agriculture through insect control. They also feed on insects that are considered forest pests by the timber industry.
“Without bats, we’d probably have more insect-borne diseases,” Dixon said.
Studies are looking at whether bats have other fungi or bacteria on their wings that could help control outbreaks of the fungus that causes white-nose syndrome.
“There’s no cure, but there’s a lot of research going on,” Dixon said.
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