Fungus that causes white-nose syndrome found in eastern Montana

HELENA – Samples taken in six eastern Montana counties this past summer have tested positive for the fungus that causes white-nose syndrome (WNS) disease in bats. The presence of the fungus Pseudogymnoascus destructans (Pd) does not necessarily confirm the presence of the disease, but biologists are closely monitoring the situation and further sampling and testing will be conducted. Montana Fish, Wildlife & Parks staff is asking the public to report any dead or dying bats they observe this winter and spring to their local FWP office.

“We are disappointed but not at all surprised at this finding,” said FWP’s Wildlife Division Bureaus Coordinator Lauri Hanauska-Brown. “As the fungus and this deadly disease have moved across the states, we knew it was only a matter of time before it reached Montana. Now, we have to work together to help understand and combat this disease.”

Pd is a powdery white fungus that grows on the skin of hibernating bats, often on the face – hence the name “white nose.” The fungus causes several problems, one of which is that it irritates bats, causing them to arouse early from hibernation and search for water and food. Food is obviously scarce in winter, and this early arousal can exhaust fat stores that bats need to survive the winter. WNS is not known to affect humans, pets, livestock or other wildlife.

In May 2020, North Dakota Game and Fish Department reported a cluster of bat deaths from WNS just over the Montana border. This put FWP staff on full alert, and sampling efforts became more crucial.

FWP temporarily prohibited the capture of all live bats due to unknown risks of COVID-19-infected humans inadvertently transferring the virus to bats. To substitute for sampling of live bats, biologists collected bat droppings at eastern Montana roosts in May and June. During this effort, no unusual mortalities were observed that were associated with WNS, but summer is not the typical season to find bats sick with this disease.

Mid-to-late winter is when bats infected with this disease tend to become sick or die, due to the tendency of the fungus to rouse them out of hibernation. Therefore, biologists will want to investigate unusual bat activity such as seeing bats out during the cold and sick or dead bats found on the ground. This is where FWP needs the public’s help: by being on the lookout.

WNS has been in North America since at least 2006, killing an estimated 6.7 million bats. It has been confirmed in 35 states and seven Canadian provinces. It can wipe out entire colonies of bats and has caused dramatic population declines in eastern states.

In some cases, WNS has been unintentionally transferred to different bat roost sites by human activity, as the microscopic Pd fungal spores can easily be transported on clothing and equipment. FWP asks that anyone that has been in or around caves and other roost sites to be extremely proactive about cleaning their equipment and clothing to prevent further spread of this disease. Recommendations for decontaminating gear can be found here.

Over the last several years, FWP has been using acoustic-recording equipment to help identify populations, species and distributions of bats across the state. This will hopefully give biologists a good baseline to see how Pd, or WNS, may affect current and future populations.

FWP staff asks anyone who sees a sick or recently deceased bat or group of bats not to handle them but to notify health officials or state biologists, who can provide further guidance. Callers can reach the FWP Wildlife Health Lab in Bozeman at 406-577-7882, or they can contact a biologist at their local FWP office.

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