White Nosed Bat Syndrome Update

May 2017 Update
In mid-April 2017, a local rehab facility that specializes in rescuing bats, received a call about a bat unable to fly near North Bend in King County. A WDFW biologist responded and located the bat, which had died before he arrived. Upon examination, the bat showed signs of white-nose syndrome. Rather than being soft and flexible, the bat's wing membranes were sticky. Using a UV light, the biologist found some areas that shined a distinctive orange color, one way that scientists and biologists can detect possible WNS infections.

The bat was shipped to the USGS National Wildlife Health Center for testing. Scientists tested the bat's wing which showed the fungus was present, and additional tests confirmed the bat had the disease. Because several species of bats in the genus "Myotis" live in Washington, scientists conducted tests to determine the bat species based on its DNA. The bat species was confirmed to be Yuma myotis (Myotis yumanensis), a common bat found in the western U.S. This is the first confirmation of WNS in this species of bat.

Learn more about this finding and what researchers are doing to stop the spread of White-nose syndrome in Washington.


What is White-nose syndrome?

White-nose syndrome is a disease caused by the fungus Pseudogymnoascus destructans. The disease is estimated to have killed over six million bats in eastern North America since 2006, and can kill up to 100% of bats in a colony during hibernation.

In March 2016, Washington's first case of white-nose syndrome was confirmed in a Little Brown Bat (Myotis lucifugus) near North Bend, 30 miles east of Seattle. Though the disease has devastated bat populations in eastern North America, we do not yet know how it will impact western bats.  In general, bats in Washington do not hibernate in large groups like eastern North American bats. Thus, the spread of the disease in western North America may be different.

The fungus can grow on the nose, wings and ears of an infected bat during winter hibernation, giving it a white, fuzzy appearance. Once the bats wake from hibernation, this fuzzy white appearance goes away. Even though the fungus may not be visible, it invades deep skin tissues and causes extensive damage.  Affected bats arouse more often during hibernation which causes them to use crucial fat reserves, leading to possible starvation and death. Additional causes of mortality from the disease include wing damage, inability to regulate body temperature, breathing disruptions, and dehydration.

The fungal disease is spread primarily from bat-to-bat contact. Bats can also contract the disease from an environment where the fungus is present. People can carry fungal spores on clothing, shoes, or recreation equipment that has come in contact with the fungus.  Appropriate decontamination for clothes and equipment used in areas where bats may live is critical to reduce the risk of spreading this catastrophic bat disease.

Species affected in Washington

As of May 2017, a Little Brown Bat (Myotis lucifugus) and a Yuma Myotis (Myotis yumanensis) have tested positive for white-nose syndrome in Washington. In addition, a Silver-Haired Bat (Lasionycteris noctivagans) tested positive for the fungus, but did not show signs of white-nose syndrome.

To date, it is unknown which of Washington's 15 bat species will be affected by the fungal disease. We need to gain more information not only on the disease in Washington, but also on our bat populations.  

White-nose syndrome is not known to pose a threat to humans, pets, or other animal species.

Clinical signs of white-nose syndrome

Clinical signs of White-nose syndrome in bats include:

  • Dehydrated, wrinkled or damaged skin on wings
  • Loss of flight
  • Emaciation

Bats Need Your Help

  • Contact the Washington Department of Fish and Wildlife immediately if you suspect you have seen bats with this condition. 
  • Do not handle live bats. If you have found a sick or dead bat, please report it using the online reporting form.
  • Report groups of bats you see using the online observation reporting form. This information will help us understand our bat populations and monitor white-nose syndrome in Washington. 
  • Do not spread white-nose syndrome in Washington and limit disturbance to roosting bats.  Avoid entering areas where bats may be living to limit the potential of transmitting the fungus that causes the disease and disturbing vulnerable bats.  Do not allow dogs to access areas where bats may be roosting or overwintering as they may act as carriers of the fungus to new sites.  
  • Clean your clothing and gear if you come into contact with crevices in rock cliffs, talus areas, caves or mines. If possible use the decontamination guidelines at www.whitenosesyndrome.org
  • Improve bat habitats. Reduce lighting around your home, minimize tree clearing, and protect streams and wetlands. Try to incorporate one or more snags into your landscape keeping old and damaged trees when possible. Snags provide important habitat for bats and other backyard wildlife. For more information on living with bats, and instructions for how to build a bat house, visit: http://wdfw.wa.gov/living/bats.html

Importance of Bats

Bats are valuable members of ecosystems around the world, saving farmers in the U.S. alone over $3 billion annually in pest control services. One colony of bats can consume many tons of insects that would otherwise consume valuable crops, or threaten human health and well-being. Many species of bats are also valuable for the pollination of plants and dispersal of plant seeds.

Over six million bats are estimated to have died due to this disease over the past few years in the eastern US and Canada, with as much as 100% mortality in some colonies. This disease could possibly lead to the extinction of some bat species.