Scientific name: Pseudogymnoascus destructans
What Is It?
White-nose syndrome is a disease caused by the fungus Pseudogymnoascus destructans. The fungus infects bat colonies during winter hibernation. It grows on the wings, ears, and muzzle of the bat, which disrupts internal processes, such as temperature regulation. This causes bats to wake from hibernation too early and burn critical fat stores needed to survive the winter. In addition, the fungus may damage the wings so severely that the bat cannot fly. Many species of bats can be infected with white-nose syndrome. Four of these species live in Washington: the little brown bat (Myotis lucifugus), western long-eared bat (Myotis evotis), fringed myotis (Myotis thysanodes) and Yuma myotis (Myotis yumanensis). The mortality rate for some species, such as the little brown bat, can be 90-100 percent. Other bat species found in Washington may be carriers of the fungus without contracting the disease.
Is It Here Yet?
Yes. The disease was found on a little brown bat near North Bend in 2016 and on a Yuma myotis in 2017. As of 2025, ten Washington counties have confirmed cases of white-nose syndrome, and twenty-two counties have the fungal pathogen present.
Why Should I Care?
White-nose syndrome is very dangerous to bats and could lead to the extinction of bat species. A drop in bat populations will mean a significant increase in populations of their insect prey, some of which are agricultural pests.
How Can We Stop It?
The fungus that causes white-nose syndrome is primarily spread by bat-to-bat or bat-to-environment contact, but gear and clothing that contact infected environments can spread the fungus to new locations. To limit its spread, clothing and gear should be decontaminated after entering areas where bats might roost, including caves. Do not handle living or dead wild bats. For more information and decontamination protocols, see: https://www.whitenosesyndrome.org/resources
What Are Its Characteristics?
White-nose syndrome is primarily identifiable by the white, fuzzy, fungal growth on the noses, wings, or ears of infected bats. The fungus will be visible only on hibernating bats. Once the bats are active, the fungus is no longer visible, but other signs include difficulty flying or damaged wings.
Additional Photographs
