The fungal disease that has killed more than 6 million bats in North America was confirmed in Washington State yesterday by federal biologists. The discovery of a little brown bat (Myotis lucifugus) infected with White-nose Syndrome in North Bend, Wash., about 30 miles east of Seattle, marks the first time the disease has been documented in the western United States.

Bat with White-Nose Syndrome/CDC
Bat with White-Nose Syndrome/CDC

“The discovery of the disease almost 1,300 miles from the previous westernmost detection of the fungus in Nebraska is devastating news,” says Katie Gillies, Director of Imperiled Species for Bat Conservation International. “Such a massive jump in geographical location leads us to believe that we humans are most likely responsible for its most recent spread”.

First documented in North America in 2007 in eastern New York, WNS has now spread to 28 states and five Canadian provinces. WNS is named for the fuzzy white growth found on bats infected with the Pseudogymnoascus destructans fungus. The fungus grows on the faces and wings of hibernating bats, repeatedly rousing them from hibernation and causing them to burn through their fat stores. Dehydrated and without food, the bats starve to death before spring.

The disease has devastated hibernating bats in the east, with the three most affected species, including the little brown bat, experiencing losses exceeding 98 percent in some states. The discovery of the disease in the west is a dire wake up call for all regions in North America, as biologists expect the disease to spread from this new epicenter.

“Everyone from state and federal agencies to individual cavers need to redouble their commitment to decontamination, especially in the western states. We need to focus on minimizing the spread of this fungus by following decontamination guidelines, increasing surveillance and ramping up our investment in potential treatments” says Gillies.

The species at the center of this sad discovery, the little brown bat, is currently under internal review by the U.S. Fish and Wildlife Service for listing under the Endangered Species Act. Already facing devastating population crashes in the east; this new finding should expedite the need for the Service to complete their review and provide protections for the little brown bat under the Endangered Species Act.

”This is a terrible new chapter in the fight against WNS”, says Gillies.  “We have as many as 16 western bat species that are now at risk.  We have always feared a human-assisted jump to a western state.  Unfortunately, our fears have been realized, and western North America – a bastion of bat biodiversity – may now expect impacts like we have seen in the East.”