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White-Nose Syndrome in Bats
White-Nose Syndrome in Bats

What Is White-Nose Syndrome?

This disease has been given the name white–nose syndrome (WNS) because of the telltale white fungus growing on the face, ear, and wing tissue of infected bats while they hibernate. Pseudogymnoascus destructans is a cold loving fungus that thrives from 5 to 15 ºC (41 to 59 ºF) - the same range of temperatures typical of bat hibernacula. Hibernating bats reside in an inactive state during winter, turning off their immune system while in deep sleep, making them vulnerable to the fungal invasion. 

​Infected bats may arouse from hibernation to attempt to deal with the fungal infection that causes severe circulatory damage in the tissue. Due to frequent arousals, these bats prematurely burn up their fat stores and starve to death before insects become available in spring. 

The earliest evidence of WNS was at a cave in New York in 2006. Since then, millions of bats have died from the disease. WNS has killed whole wintering populations of bats in the eastern U.S. as they hibernate in caves or mines.

The fungus that causes WNS on bats fluoresces when put under UV light. Photo taken by CPW's Karen Fox.The fungus was first confirmed in Colorado during the summer of 2022 and the first bat to die of the disease, a Yuma myotis, found at Bent’s Old Fort National Historic Site in the spring of 2023. Since that time, the fungus has been confirmed in four additional counties and a second species, the little brown bat, has died from WNS. CPW continues to monitor the spread of the disease in Colorado and is conducting vaccination trials to see if proactive measures can be used to protect bats. See the "Where is WNS NOW" map​.

Bats are an essential and beneficial part of the ecosystem. Bats play critical roles in insect control, plant pollination, seed dissemination, cave ecosystems, and provide food for other animals. Please see​ for more information.

How Cavers can help prevent WNS

Aspects of the geographic spread suggest that humans may transmit WNS from infected sites to clean sites. This kind of spread is most likely occurring from boots, clothing and equipment that are not properly cleaned and decontaminated between sites. Because of the devastating effects of WNS, it is critical that people assume responsibility for the potential spread of WNS.

Please do not use ANY gear or clothing in the west that you have used in caves/bat roosts in areas where WNS has been confirmed. There is a risk that you could spread the fungus that can kill bats.

Please ensure ALL gear and clothing used in western caves and roosts has been cleaned and disinfected before entering any other caves/roosts in the west. Soaking equipment for at least 20 minutes in water kept at 120 degrees, or using approved disinfectants such as Lysol all-purpose professional cleaner is recommended.

Please see the official decontamination guidance and protocols for researchers and cavers off the white-nose syndro​ website and visit for past WNS survey information.

What to do if a Bat is found

A bat afflicted with WNSBecause bats also can be affected by other health problems, including rabies, the Colorado Parks and Wildlife discourages members of the public from handling bats if possible. Sick or injured bats can be reported to the County Health Department. If you need to dispose of a dead bat found on your property during the summer or fall, pick it up with a plastic bag over your hand or use disposable gloves. Place both the bat and the bag into another plastic bag, spray with disinfectant, close the bag securely and dispose of it with your garbage. Thoroughly wash your hands and any clothing that comes into contact with the bat. If a dead bat is found during late winter or spring, please cover the bat with a box, can, bucket or similar container and contact your local local Colorado Parks and Wildlife Officer or County Health Department to collect it.

If you see a band on the wing or a small device with an antenna on the back of a bat (living or dead), contact your state wildlife agency or your nearest service field office as these are tools for biologists to identify individual bats.

Working with or collecting Bats

As a reminder, anyone interested in working with and collecting bats is required to follow the Colorado Parks and Wildlife’s special licensing guidelines in order to get a permit. See the following documents:

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