Montana Fish, Wildlife & Parks has confirmed the presence of the fungus that causes white-nose syndrome on two bats captured at Libby Dam in Lincoln County.
The detection at Libby Dam is a concerning development in the spread of the disease for a couple reasons. This is the first detection west of the Continental Divide in Montana. Secondly, Libby Dam is one of Montana’s largest known maternity roosts.
A recent detection in Bonner County, Idaho, also suggests the fungus is progressing from both eastern and western fronts across the region.
“Finding the fungus here is concerning because both Yuma myotis and little brown myotis, the species roosting within the dam’s Visitor Center, are susceptible to white-nose syndrome,” said Shannon Hilty, FWP’s state bat biologist.
“This reinforces the importance of monitoring populations to track trends as well as working to implement management actions that will either mitigate the effects of the disease or aide in population recovery.”
There are no public health concerns associated with white-nose syndrome in bats.
FWP staff have been monitoring and sampling bat populations across the state to track the spread and impacts of this disease. Work to date has suggested declines in Montana’s susceptible bat species in the eastern half of the state due to white-nose syndrome. This year’s sampling effort included 19 sites, the majority of which were located in the western part of the state where the fungus had yet to be detected. FWP is still awaiting results for some additional sites.
Libby Dam hosts a large mixed-roost of Yuma myotis and little brown myotis bats. While no visible symptoms of the disease were observed, many of the bats appeared dehydrated. FWP staff were unable to identify the precise species of affected bats during this latest survey due to overlapping traits and high social activity, known to impact acoustic ID, but historical data suggests the majority are likely Yuma myotis. Both species face heightened risk from white-nose syndrome, which has devastated bat populations across North America.
First documented in New York in 2006, white-nose syndrome has since spread to 40 states and eight Canadian provinces, killing millions of bats and causing declines upwards of 90-98 percent in some populations in eastern North America.
The fungus, Pseudogymnoascus destructans, which causes the disease, was first confirmed in Montana in 2020 in samples from bridges in several eastern Montana counties. The first confirmed case of the disease itself in Montana came about a year later, in spring 2021 in eastern Montana.
The fungus attacks bats during hibernation, disrupting their energy balance and often leading to starvation, dehydration, or death.
“Bats play a vital role in Montana’s ecosystems, consuming vast amounts of insects and supporting healthy forests and agriculture,” said Hilty.
“A disease like this can damage our ecosystems, our economy, and ultimately, have large impacts on the wildlife and people that reside within our state. Protecting bats from white-nose syndrome is critical.”
What can the public do?
Cavers, climbers, and recreationists that visit areas with roosting bats should remove dirt and mud from shoes, gear, and clothing before leaving a site; bag these items to take home; and clean items promptly. People that visit multiple areas where bats might reside should follow decontamination protocols to help stop the spread.
Meanwhile, in Oregon, the fungus that causes white-nose syndrome has been detected in bats in Clatsop County.
Samples analyzed by U.S. Geological Survey confirmed the presence of the fungus in guano collected from a bat roost at Lewis and Clark National Historical Park. This is the first documented case of the fungus in Oregon.
National Park Service biologists collected the sample as part of a federal and state multi-agency bat disease and surveillance effort in the Pacific Northwest coordinated by USGS. The sample was likely from a Yuma myotis, which migrate from winter roosts to maternity roosts in the spring. No bats in Oregon have been observed with signs of white-nose syndrome, however, bats can carry the fungal spores on their skin, groom themselves, and shed them briefly afterward in their feces or guano.
White-nose syndrome has killed millions of bats in North America since its detection in New York in 2007 and continues to spread. At least 40 states have detected the disease and five others have detected the fungus but no disease. The fungus spreads primarily through bat-to-bat contact during hibernation.
Bats suffering from disease can have the fungus growing on their muzzle, ears and wings during hibernation, causing irritation and damage to the bat’s skin. Bats with white-nose syndrome also wake up more frequently during hibernation and use up critical stored fat reserves faster than normal. The excessive energy expenditure and dehydration during winter in diseased bats can lead to starvation and death.
Since 2011, Oregon Department of Fish and Wildlife and federal partner agencies (National Park Service, U.S. Geological Survey, Bureau of Land Management, U.S. Forest Service, and U.S. Fish and Wildlife Service) have surveyed for the fungus and white-nose syndrome across the state with the assistance of wildlife rehabilitators, the Northwest Bat Hub and the Oregon Department of Health. Surveys are completed throughout the year in places where bats spend the winter, spring sites where they raise pups, and other roost sites.
ODFW Wildlife Health and Population Lab biologists and veterinarians along with federal scientists will identify additional sites for surveillance around the positive sample area this winter and are planning increased bat population monitoring across the state. Samples submitted by bat biologists are tested by the Oregon State University Veterinary Diagnostic Laboratory in Corvallis and the USGS National Wildlife Health Center in Madison, WI.
The White-nose Syndrome Response Team is led by the U.S. Fish and Wildlife Service and combines the knowledge and resources of experts across the continent to conserve bats and address the threat of white-nose syndrome through the implementation of a national response plan. Information on some of the treatment innovations developed by the response team to manage white-nose syndrome is available here: Preventing and treating white-nose syndrome.
Oregon is home to 15 species of bats, most of which are Species of Greatest Conservation Need. Learn more about them in the State Wildlife Action Plan, which serves as a roadmap for protecting Oregon’s at-risk species and their habitats.
In North America, 12 bat species, including two federally endangered species and one threatened species, have been confirmed with white-nose syndrome. The fungus has been found on an additional nine species without confirmation of the disease.
Learn more about white-nose syndrome and how it affects bats at whitenosesyndrome.org