White-Nose Syndrome
Causative Agent
  • White Nose Syndrome, or WNS, is a fungal disease affecting hibernating bats (Vespertilionidae).
  • The disease is named for the white fungus, Pseudogymnoascus (Geomyces) destructans, that infects the skin of the muzzle, ears, and wings of hibernating bats.
  • WNS is associated with extensive mortality of bats (millions of animals) in eastern North America.
  • First documented in New York state in the winter of 2006-2007, WNS has spread rapidly across the eastern United States and Canada
  • The fungus that causes WNS has been detected as far west as Oklahoma.
  • Evidence suggests that WNS may be caused by an invasive strain of the fungus, probably from Europe.
Click on image to enlarge.
White-Nose Syndrome White-Nose Syndrome
White fungal growth often appears on the muzzles of hibernating bats.
Geographic: Click on map to enlarge.
  • WNS has not been detected in British Columbia as of December 2014. 
White-Nose Syndrome Map 2013 
  • Mainly observed during the winter months. 
Distribution of WNS as of December 2013
Hosts, Transmission and Life Cycle
  • Bat species known to be affected by WNS:
    • Big brown bat (Eptesicus fuscus);
    • Eastern small-footed bat (Myotis leibii);
    • Gray bat (Myotis grisescens) [endangered];
    • Indiana bat (Myotis sodalis) [endangered];
    • Little brown bat (Myotis lucifugus);
    • Northern long-eared bat (Myotis septentrionalis);
    • Tricolored bat (Perimyotis subflavus). 
Transmission and Life Cycle:
  • It is believed that white-nose syndrome is transmitted primarily from bat to bat.
  • WNS may also be transmitted by humans inadvertently carrying the fungus from cave to cave on their clothing and gear.
  • The fungus, Pseudogymnoascus destructans, associated with WNS, thrives in the cold and humid conditions characteristic of caves and mines used by bats. 
Signs and Symptoms
  • Bats affected by WNS may exhibit some or all of the following unusual behaviors or characteristics:
    • affected animals will often exhibit a white fungus on the muzzle, wings, ears or tail;
    • bats flying outside during the day in temperatures at or below freezing;
    • bats clustered near entrances of hibernacula;
    • dead or dying bats on the ground or on buildings, trees or other structures. 
Meat Edible?
  • Meat from bats is generally not consumed. 
Human Health Concerns and Risk Reduction
  • Thousands of people have visited affected caves and mines since white-nose syndrome was first observed, and there have been no reported human illnesses attributable to WNS.
  • To date, there is no known risk to humans from contact with WNS-affected bats.
  • Bats should not be handled for concerns over other zoonotic diseases such as rabies, and biologists and researchers should use protective clothing when entering caves or handling bats.
  • Taking precautions and not exposing yourself to WNS is urged. 
Samples for Diagnosis
  • Fresh, intact carcasses.
  • Photos of affected animals 
Further Reading
Return to Manual Home Page Disease List - Body Region Affected Disease List - Causative Agent or Risk Factor Disease Surveillance Form Glossary Contact Information
Return to Manual Home Page Return to Disease List - Body Region Affected Return to Disease List - Causative Agent or Risk Factor Disease Surveillance Form Download Glossary Contact Information