SHERIDAN — Wyoming wildlife researchers discovered the first sign of white-nose syndrome in bats in the state May 16 at Fort Laramie National Historic Site in Goshen County. The potential for the fungus that precursors the disease to come to the Sheridan area poses a slight threat but has yet to be discovered.

White-nose syndrome is a disease affecting hibernating bats, according to the White-Nose Syndrome website.

A white fungus appears on the muzzle and is associated with extensive mortality of bats. Bats with the disease will act strangely during cold winter months, including flying outside in the day and clustering near the entrances of caves and mines where bats hibernate.

The disease has killed more than 5.7 million bats in eastern North America, and in some hibernacula, or caves and mines, 90 to 100 percent of bats have died. 

The fungus does not necessarily mean the bat will contract the disease, but bats are more prone with the initial fungus. 

Scientists first detected the fungus, Pseudogymnoascus destructans, in New York in 2006. They believe the fungus carried over from Eurasia to the U.S., and it continues to spread west. Nichole Bjornlie, a Wyoming Game and Fish Department nongame mammal biologist out of Lander, said this is the first documentation of the fungus in the more western states, and researchers and scientists are not sure how the species will react to it.

The fungus, which does not confirm white-nose syndrome in the bat, was found in a western small-footed myotis (M. ciliolabrum) in Badlands National Park, South Dakota, in May. A Wyoming field team detected five bats with P. destructans in the park. Wyoming has been sampling for the fungus since 2014 with no previous detections until it was detected in a little brown bat at Fort Laramie.

“This is a saddening discovery. Bats are important species because they are incredible predators of insects,” said Tim Woolley, the WGFD’s statewide wildlife and habitat management supervisor. “As voracious insectivores, bats are vital for healthy ecosystems and contribute at least $3 billion annually to the U.S. agricultural economy through pest control and pollination.”

Numerous species of bats reside in and around Sheridan County and the Bighorn National Forest. The most popular include the little brown bat and the Townsend’s big-eared bat. The little brown bat carries P. destructans in several parts of the United States and inhabits a majority of the country, including Sheridan County. The Townsend big-eared bat also lives in Sheridan County and carries the fungus in other states, but it has not yet contracted white-nose syndrome from it.

Cottonwood trees, caves in the Bighorn National Forest, bat houses and older houses in Sheridan County all support bat populations.

Sheridan’s Wyoming Game and Fish Department wildlife biologist, Tim Thomas, said he’s less familiar with the disease progression and is not sure of the risk associated with Sheridan County’s bat population for contracting the disease.

“It’s dependent on the different bat species, because we have numerous bat species in the area,” Thomas said. Citizens in the area will not be affected directly, but there are ways to help the spread of the disease and risk losing more of the bat population in the U.S. Bjornlie said Wyoming faces a large potential to really impact the little brown bat species. 

“There’s a potential for massive mortality,” Bjornlie said of both the little brown and Townsend big-eared bats. “The Townsends can carry the fungus from place to place but may not be affected by it.”

The state of Wyoming and park service’s strategy is to increase coordinated management by limited access to sites where bats roost and hibernate and to broaden surveys of those sites to monitor any spread of the fungus. Bjornlie said researchers still consider Sheridan County free of disease and fungus; however, they will continue to monitor the bat populations in the area.