White-nose Syndrome (WNS) is a fungal disease that has killed more than five million hibernating bats across the northeast and mid-Atlantic United States and Canada during the past seven years and continues unchecked.  Bats with WNS may exhibit a white fungus that is found around the muzzle, ears, and especially the wings of affected individuals.

The agent of WNS is a newly described fungus Psuedogymnoascus destructans (Pd), which causes an invasive skin infection that is the primary characteristic of this disease. As of June 2014, WNS has spread to 25 states and 5 Canadian provinces.  Mortality of this magnitude from an infectious disease is not only unprecedented among bats worldwide, but also among wild mammals.

We don’t entirely understand how the fungus kills bats. One possibility is that fungal infection disturbs bats while hibernating which leads to more frequent or longer awakenings and accelerates the use of fat reserves. However, fat depletion is not consistently observed among all bats with WNS. Another option is that some infected bats shift from areas in caves or abandoned mines with stable temperatures to entrances with more variable temperatures. Sometimes bats depart early from hibernacula, exposing themselves to cold which could account for some mortality. However, greater focus is currently on the fungal damage that WNS inflicts on wing membranes. Wings play a key role in maintaining water balance, temperature, blood circulation, and skin respiration so disrupting any of those key functions would increase mortality.

Bat-to-bat: Bat-to-bat transmission of Pd has been documented in lab conditions and is believed to be the primary route of transmission of fungal spores. 

Infected environment-to-bat: Recent research indicates that viable fungus persists in bat guano, and on the floors and walls of contaminated sites. The fungus remains viable in cave sediments “for a long time,” and can even persist in the absence of bats.

Cave/Abandoned Mine-to-Humans-to-Bats: Aspects of the geographic spread suggest that humans can transmit WNS from infected sites to clean sites. Both the U.S. Geological Survey and the New York State Department of Environmental Conservation have isolated fungal spores on equipment and clothing after exiting a contaminated cave. 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.

WNS is in caves and mines that have been visited by hundreds of people during the past six years, yet there have been no reported human 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 risks.

• Avoid entering caves and mines to protect resident bats.
• If a cave or mine must be entered, clothing and gear must be decontaminated following current guidelines (white-nosesyndrome.com).
• Do not handle animals that appear sick or are found dead.
• Advise the local BLM Field Office, the U.S. Fish and Wildlife Service, or the New Mexico Department of Game and Fish if you have seen bats that may have this disease, or if you see bats behaving strangely during daylight hours.