Colorado Caves and White Nose Bat Syndrome

What is White-Nose Syndrome?

White-nose Syndrome (WNS) is a fungal disease that has killed more than one million bats across the northeast and mid-Atlantic United States.  Bats with WNS may exhibit a white fungus that is found around the muzzle, ears, or wings of affected individuals.  Other bat symptoms include moving to the entrance of the caves and often coming out of the caves and flying around in the middle of the day during winter months.  Bats displaying this abnormal behavior have reduced fat reserves.  Although it is normal for bats to occasionally interrupt their winter roosting, they are not equipped to withstand the drain on their fat reserves resulting from flying more often and during the day, a behavior thought to be caused by the irritation of the fungus.  Many bats are non-responsive and many have been found dead both inside and outside caves. 

What causes the bats to die?

Bats affected by WNS are basically starving to death, but scientists don’t know what is triggering the starvation.  Studies are under way to determine if the bats are going into hibernation underweight or if they lose their body fat at an accelerated rate during hibernation.  If bats lose more body fat than normal during hibernation, they do not have the energy reserves to survive until spring.  If they are going into hibernation underweight, scientists will explore the possible reasons for this.

What do we know about bat species within BLM Colorado?

In general, bats are very guarded.  Thus we have limited knowledge of where bats roost in Colorado.  Roosts in caves and mines with moist, cool conditions are of highest risk for WNS.

The BLM Colorado Abandoned Mine Lands (AML) database has about 3,200 recorded sites.  These sites are estimated to have more than 5,000 features such as adits, shafts, prospects, etc.  Typically, BLM Colorado does not inventory mines for bats unless we plan to complete a mine closure for public safety.  Most of the bat data collected for BLM Colorado was provided through Colorado Parks and Wildlife, and was for openings that are now closed or bat gated.

BLM Colorado also has an estimated 20 caves and is still in the process of surveying those caves. We currently don’t have information on which of these caves serve as roosting and/or habitats for bats.

How is White-Nose Syndrome Spread?

Bat-to-Bat transmission of Geomyces destructans has been documented in lab conditions and the geographic pattern of spread appears to support lab findings. It is also possible that other unknown agents associated with WNS are spread bat-to-bat.

Cave-to-Human-to-Bat – 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 clothing and equipment that are not properly cleaned and decontaminated between sites. Formal testing of human-spread WNS is ongoing. Because of the devastating effects of WNS, it is critical that people assume responsibility for the potential spread of WNS.

Does White-Nose Syndrome pose a risk to human health?

WNS is in caves and mines that have been visited by hundreds of people during the past three years, yet there have been no reported illnesses attributable to it.  However, because scientists are still learning about WNS, we do not know if there is a risk to humans from contact with affected bats, and we cannot advise you about human health risk.