In the winter of 2006-07, the New York Department of Environmental Conservation found approximately 10,000 bats of the genus Myotis (little brown bats, M. lucifugus and Indiana bats, M. sodalis) dead and dying in four caves in New York. This massive die-off caused a frenzy of research throughout the country. Through this research, it has been determined that the die-off was caused by a disease known as White-nose Syndrome (WNS). It gets its name from the characteristic white, fuzzy fungus that coats the nose and wings of hibernating bats. WNS is caused by a cold-loving fungus, Pseudogymnoascus destructans (Pd). Pd infects the exposed skin on bat's wings during hibernation, which ultimately causes the death of the bats infected. The fungus is irritating and causes bats to wake up more frequently during hibernation, depleting their stored fat reserves. It also weakens the epidermis, skin, on the wings causing abrasions and holes to form. Bats infected with WNS can transmit the disease and Pd spores to other bats, even through the summer. Additionally, experts believe humans can unintentionally carry the Pd spores that cause WNS on their clothing from contaminated sites, which may increase the spread of the disease. There have been no reported human illnesses attributed to WNS.
The most supported origin for the fungus is thought to be Europe. Bats dating back to 1918 have been found to have the pathogen in Europe. The leading thought is that bats in Europe once went through a similar decline as bats in the United States, but they eventually recovered as resistant bats began to pass on their genetics to offspring resulting in bats that are immune to WNS. Since 2006, WNS has killed millions of bats in North America, particularly affecting several Myotis species, Perimyotis subflavus (tri-colored bat) and Eptesicus fuscus (big brown bat). At of the end of 2017, WNS was confirmed in 31 states and 5 Canadian provinces, as well as having evidence of the fungus in two additional states (Texas and Mississippi). However, these statistics are constantly changing, as bats continue to spread the disease as they migrate from their summer roosting sites to their winter hibernating sites and interact with more and more bats. In order to see the most recent updates on WNS, you can access the national WNS page at www.whitenosesyndrome.org. In March 2011, the first case of WNS was confirmed in an abandoned mine in Lawrence County, Ohio. Since then, WNS has been found in counties through Ohio. Therefore, all counties should be treated as if they are WNS positive because any Ohio bat could be infected.
The scope of bat mortality associated with WNS is unprecedented in recent history. The fast rate of WNS spread across the eastern U.S., the high rate of mortality, and working with a new pathogen, have made this a challenging wildlife disease event. Scientists are actively evaluating the bat species that are most affected, surveying caves for the presence of bats and developing strategies for disease management.
Bats can use all the help that they can get and one of those ways to help is to spread the word. Educate friends and family on the impacts of WNS and how to avoid accidentally spreading it. If you enter a cave or a mine that could be a potential hibernacula for bats, decontaminate your clothes. Make sure to take all clothes and equipment and either bleach them or submerge them in hot water, 120 degrees Fahrenheit, for twenty minutes. This needs to be done before exposing those same clothes to any other caves or mines and it is recommended that you do it as soon as you arrive home. If you have any questions about decontamination, please review the national decontamination protocols. Every little bit counts!