When White Nose Syndrome (WNS), a fungal disease that kills certain bats, was found in Oklahoma in 2011, Colorado Parks and Wildlife (CPW) began putting gates on certain caves in the state to give hibernating bats a head start.
“The cave closures have been done proactively,” explained Tina Jackson, CPW Species Conservation Coordinator and bat expert. “We work with the Forest Service and the Bureau of Land Management to protect those roosts that are significant because, as the fungus started moving west, we started picking it up closer and closer to Colorado.”
WNS showed up in North America about 17 years ago. CPW started finding the fungus in Colorado caves in 2022. The first infected bat, a female Yuma bat, was found at Bent’s Old Fort National Historic Site near La Junta on March 29, 2023. CPW is mainly concerned with the myotis species of bats, which includes the little brown bat. “The other ones we’re keeping an eye on are the tri-colored bat, big brown bat, and Townsend’s big-eared bat,” said Jackson.
WNS is caused by the virus Pseudogymnoascus destructans (PD). Symptoms include a white substance on the nose and “unfurred” skin of hibernating bats. Hibernation is key to spreading the disease, sort of like “Invasion of the Body Snatchers” when the virus did its work while humans slept. Unlike the body snatcher virus, however, WNS does not kill the bats outright.
“That fungus is itchy. It’s making [the bats] wake up more frequently in hibernation, which is burning through their fat reserves faster,” Jackson explained. “Bats have a lot of surface area for their body size because of those large wings. And it’s actually eating away at a lot of that wing tissue, which is causing a lot of internal disturbance to their systems.”
The U.S. Fish and Wildlife Service website shows that infected bats have been found in 40 states and eight Canadian provinces. PD has also been found in three more states and two additional provinces. WNS is killing up to 95% of certain species of hibernating bats.
Jackson told The Sopris Sun that the origin of WNS is unknown, but bats in Europe and Asia may have evolved with the fungus. “Those bats seem to respond a lot better to the fungus than our bats do,” she said. “They’re able to handle it like [humans] can handle a common cold.”
There are more strains of the fungus in Asia and Europe but only one in North America. “You can really tell it’s one strain that was introduced and is spreading across the country,” she said. “It could have been a researcher who brought the fungus here or a bat that stowed away on a cargo ship. Hard to say exactly.”
The spread of WNS is a prime example of why CPW and other wildlife agencies want to stop people from transporting wildlife across borders. “Because we never really know what’s going to be brought in and how that’s going to interact with our local species,” she said.
So far, WNS has not jumped species from bats to humans. It only affects hibernating bats. When Jackson says that humans can bring the fungus to the bats, it’s not because humans are sick. PD can live in a hibernation area even when bats are not present. It can live in the mud, on the cave walls — any place that’s cold, dark, and damp. It does not like heat, sunlight or UV rays.
Humans can transfer the virus from site to site via clothing, boots, headlamps or equipment. “If you were to come home from caving and leave your headlamp on your back patio for a week, the fungus is probably not going to survive,” Jackson explained. “You come out with your hiking boots encased in mud and you leave those outside, that mud may actually provide some sort of protection for the fungus and it may actually survive sitting on your patio for a week.” Hence the need for decontamination before you put everything away, usually with bleach or soap and very hot water.
Jackson loves bats and would like it if everybody else did, too. Bats provide a lot of beneficial services for humans, like eating mosquitoes, agricultural pests and other night-flying insects. “The other issue is bats sit in the middle of the food chain,” she explained. “So when we lose our bats — raptors, owls and, in some cases, snakes and raccoons lose an important food source.”
More information on bats and WNS is on the CPW website and at coloradobatwatch.org