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Little brown bat found in western Washington in March 2016. The fungus damaged the bat’s wings making it unable to fly. Photo: Progressive Animal Welfare Society (PAWS)
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July 2016 Update
Since Washington’s first case of white-nose syndrome was confirmed in March, WDFW and other state and federal agencies have worked to monitor bat populations and test for Pseudogymnoascus destructans (Pd), the fungus that causes the disease. So far, all samples collected from live bats and the environment have tested negative for Pd.
The Washington State Department of Health receives dozens of bat carcasses each year for rabies testing, and this provides the opportunity to also screen these bats for Pd. As a result, one Silver-Haired Bat recently tested positive for Pd, but did not show signs of white-nose syndrome. This bat was originally collected in the same month and in the same county as the first confirmed Washington case of white-nose syndrome.
For more information on this finding, see the USGS Wildlife Health Bulletin
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 aggregations like bats do in eastern North America. 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.
To date, it is unknown which of Washington’s 15 bat species will be affected by the fungal disease. A single documented case in a Little Brown Bat indicates that this species is vulnerable to the fungus. We need to gain more information not only on the disease in Washington, but also on our bat populations.
In eastern North America, seven cave hibernating species are afflicted by white-nose syndrome. Two of these species are found in Washington: the Little Brown Bat (Myotis lucifugus) and Big Brown Bat (Eptesicus fuscus).
White-nose syndrome is not known to pose a threat to humans, pets, or other animal species.
Clinical signs of White-nose syndrome in bats include:
- Dehydrated, wrinkled or damaged skin on wings
- Loss of flight
|Normal wing of little brown bat.
Photo: Greg Falxa, WDFW
Little brown bat with
skin infection on wing.
Photo: Progressive Animal Welfare Society (PAWS)
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- 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 enter information into 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 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. For more information on living with bats, and instructions for how to build a bat house, visit: http://wdfw.wa.gov/living/bats.html
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.