Bat-killing fungus found near Rimrock Lake in Yakima County

YAKIMA — An invasive fungus that causes white-nose syndrome in bats continues to spread in Washington, with the fungus detected in late spring near Rimrock Lake.

During spring and summer field work this year, scientists with the Washington Department of Fish and Wildlife in partnership with the U.S. Forest Service detected the fungus or disease in Yakima, Chelan and Mason counties, according to a news release.

WDFW scientists collected guano samples in late spring 2021 from a bat colony showing no signs of disease on Forest Service land near Rimrock Lake. Testing confirmed the presence of the fungus that causes white-nose syndrome. The bat genus was Myotis, but the specific species is unknown.

“These recent confirmations of white-nose syndrome and the causative fungus in new areas of Washington are very concerning, as they provide evidence that the disease is spreading,” said Abby Tobin, white-nose syndrome coordinator for WDFW said in the release. “This eventually may lead to population declines in several bat species that are vulnerable to white-nose syndrome.”

White-nose syndrome is harmful to hibernating bats, but does not affect humans, livestock or other wildlife. The disease is caused by the fungus Pseudogymnoascus destructans, which attacks the skin of hibernating bats and damages their delicate wings, making it difficult to fly. Infected bats often leave hibernation too early, which causes them to deplete their fat reserves and become dehydrated or starve to death.

Washington is home to 15 bat species that are important predators of night-flying insects. These bats benefit humans by eating insects that can negatively affect forest health, commercial crops, and human health.

In March 2016, the first case of white-nose syndrome in the western U.S. was confirmed in a little brown bat (Myotis lucifugus) in King County. Since then, WDFW has confirmed more than 100 cases of the disease in at least four bat species in the state. WDFW has confirmed white-nose syndrome in King, Chelan, Kittitas and Pierce counties. In addition, the fungus that causes white-nose syndrome has been detected in Lewis, Mason, Snohomish and Yakima counties.

WDFW urges people to not handle wild animals, especially if they appear sick or are found dead.

If you find sick or dead bats, groups of bats, or notice bats acting strangely, such as flying outside during the day in winter or spring, report your sighting online at or call WDFW at 360-902-2515.

Even though the fungus is primarily spread from bat-to-bat contact, humans can unintentionally spread it as well. People can carry fungal spores on clothing, shoes or recreation equipment that touches the fungus.

Source: Wenatchee World