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 22 states and five Canadian provinces have died from this devastating disease. The disease is named for the white fungus, Pseudogymnoascus 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 P. 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 P. 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, firstname.lastname@example.org
- Central U.S.: Dr. LeAnn White, 608-270-2491, email@example.com
- Eastern U.S.: Dr. Anne Ballmann, 608-270-2445, firstname.lastname@example.org
- Hawaii, Pacific Islands: Dr. Thierry Work, 808-792-9520, email@example.com
- Nationwide, single animal cases only: Jennifer Buckner, 608-270-2443, jBuckner@usgs.gov
WNS Related Links
Experimental infection of bats with Pseudogymnoascus destructans causes white-nose syndrome
Researchers have confirmed that a recently identified fungus is responsible for white-nose syndrome, a deadly disease that is sweeping through bat colonies in eastern North America. Full Article
Bat White-Nose Syndrome: An Emerging Fungal Pathogen?
A previously undescribed, cold-loving fungus has been linked to white-nose syndrome, a condition associated with the deaths of over one million hibernating bats in the northeastern United States. The findings are published in the January 9, 2009 issue of Science. Download PDF
Other WNS Publications
- Read about WNS in Microbe Magazine: A Plain Language Review
- Recovery of little brown bats (myotis lucifugus) from natural infection with Pseudogymnoascus destructans, white-nose syndrome (Journal of Wildlife Diseases 2011)
- DNA-based detection of the fungal pathogen Pseudogymnoascus destructans in soil from bat hibernacula. (Mycologia 2010)
- Wing pathology of white-nose syndrome in bats suggests life-threatening disruption of physiology (BMC Biology Journal, November 2010)
- WNS Fungus in Bats, Europe (Emerging Infectious Diseases, August 2010)
- Rapid PCR technique to detect Pseudogymnoascus destructans in bat skin (J. Vet. Diag., 2010)
- WNS Fungus in Bat, France (Emerging Infectious Diseases, Feb. 2010)
- Histopathologic criteria to confirm white-nose syndrome in bats (J. Vet. Diag., 2009)
- Species Name Published for Fungus that Causes White Nose Syndrome Skin Infection (Mycotaxon, 2009)
- Could localized warm areas inside cold caves reduce mortality of hibernating bats affected by white-nose syndrome? (Frontiers in Ecology and the Environment, 2009)