White-Nose Syndrome (WNS)

White-nose syndrome (WNS) is an emergent disease of hibernating bats that has spread from the northeastern to the central United States at an alarming rate. Since the winter of 2007-2008, millions of insect-eating bats in 19 states and four Canadian provinces have died from this devastating disease. The disease is named for the white fungus, Geomyces destructans, that infects skin of the muzzle, ears, and wings of hibernating bats.

The USGS National Wildlife Health Center (NWHC), along with the U.S. Fish and Wildlife Service and other partners continue to play a primary role in WNS research. Studies conducted at NWHC led to the discovery, characterization, and naming of the causative agent (the cold-loving fungus G. destructans), and to the development of standardized criteria for diagnosing the disease. Additionally, scientists at the NWHC have pioneered laboratory techniques for studying impacts of the fungus on hibernating bats.

To determine if bats are affected by white-nose syndrome, scientists look for a characteristic microscopic pattern of skin erosion caused by G. destructans. Field signs of WNS can include visible white fungal growth on the bat’s muzzle and/or wing tissue, but this is not a reliable indicator. Infected bats also often display abnormal behaviors in their hibernation sites (hibernacula), such as movement toward the mouth of caves and daytime flights during winter. These abnormal behaviors may contribute to the untimely consumption of stored fat reserves causing emaciation, a characteristic documented in a portion of the bats that die from WNS.

Current estimates of bat population declines in the northeastern US since the emergence of WNS are approximately 80%. This sudden and widespread mortality associated with WNS is unprecedented in hibernating bats, among which disease outbreaks have not been previously documented. It is unlikely that species of bats affected by WNS will recover quickly because most are long-lived and have only a single pup per year. Consequently, even in the absence of disease, bat populations do not fluctuate widely in numbers over time.

The true ecological consequences of large-scale population reductions currently under way among hibernating bats are not yet known. However, farmers might feel the impact. In temperate regions, bats are primary consumers of insects, and a recent economic analysis indicated that insect suppression services (ecosystem services) provided by bats to U.S. agriculture is valued between 4 to 50 billion dollars per year.

Despite efforts to contain it, WNS continues to spread. Within the last two years, the disease has been confirmed in several central states, including Alabama, Indiana, Kentucky, Tennessee, and Missouri. High mortality of bats has not yet been reported at these locations, and it remains to be seen if WNS will develop and manifest in warmer parts of the US or other temperate regions of the world with severity similar to that in the northeastern US. See the map below for WNS occurrences in North America.

WNS Occurrence by County

Map courtesy of Cal Butchkoski, Pennsylvania Game Commission.

Report WNS observations to your state conservation agency, the U.S. Fish and Wildlife Service or the USGS National Wildlife Health Center.

To report wildlife mortality events to USGS, please visit the mortality reporting page or contact a member of NWHC’s Field Investigations Team:

• Western U.S.: Barb Bodenstein, 608-270-2447, bbodenstein@usgs.gov
• Central U.S.: Dr. LeAnn White, 608-270-2491, clwhite@usgs.gov
• Eastern U.S.: Dr. Anne Ballmann, 608-270-2445, aballmann@usgs.gov
• Hawaii, Pacific Islands: Dr. Thierry Work, 808-792-9520, thierry_work@usgs.gov
• Nationwide, single animal cases only: Jennifer Buckner, 608-270-2443,jBuckner@usgs.gov

WNS Related Links

• WNS National Plan
• Histologic Severity Scoring of WNS using Wing Membrane
• White-Nose Syndrome in Bats: USGS Updates
• USGS Publications on White-Nose Syndrome
• WNS Submission Guidelines (Revised 1/3/2013)
• Subcommittee on Fisheries, Wildlife, Oceans and Insular Affairs Oversight Hearing on "Why We Should Care About Bats: Devastating Impact White-Nose Syndrome is Having on One of Nature’s Best Pest Controllers"
• Case Definitions for WNS
• WNS Sampling Methods
• Bulletin: Update on WNS - Tennessee Finding
• Fact Sheet: Investigating WNS in Bats
• Webinar on WNS: An Emerging Fungal Pathogen?
• Battle for Bats: White Nose Syndrome VIDEO (Ravenswood Media)
• WNS Threatens the Survival of Hibernating Bats in North America
• Report from WNS Science Strategy Meeting
• Listen to scientist David Blehert on NPR's Science Friday
• Fish and Wildlife Service: WNS in NE Region
  • FWS WNS Blog
  • WNS Management: Report on Structured Decision Making Initiative (Oct. 2009)
  • White-nose syndrome in bats, FAQ
  • Video of Susi von Oettingen talking about WNS
• Bat Conservation International
• Power Point presentation by Al Hicks, NY DEC
• Center for North American Bat Research and Conservation, Indiana State University