Bat-Killing Disease Confirmed for First Time East of the Cascades in Washington


The first case east of the Cascades of white-nose syndrome, an often fatal disease in hibernating bats, has been confirmed by the Washington Department of Fish and Wildlife. Kittitas County is the fourth county in Washington to be affected by the disease caused by a fungus.

The WDFW received four dead bats from a landowner outside of Cle Elum this spring. After sending the bats to the United States Geological Survey’s National Wildlife Health Center in Madison, Wisconsin, all four bats tested positive for white-nose syndrome.

White-nose syndrome is harmful to hibernating bats. It’s caused by a fungus that attacks the skin of hibernating bats and damages their delicate wings, making it difficult for them to fly. Infected bats often leave hibernation early, which causes them to lose their fat reserves and become dehydrated or starve to death. 

It is not harmful to humans, livestock or other wildlife. 

“As predators of night-flying insects, bats play an important ecological role in preserving the natural balance of your property or neighborhood. Washington is home to 15 bat species that benefit humans by eating tons of insects that can negatively affect forest health, commercial crops, and human health and well-being,” the WDFW said in a news release. 

White-nose syndrome was found for the first time in Lewis County in 2017.

At the time, that finding meant the fungus was known to exist on bats in two Washington counties, following numerous reports from King County dating back to March 2016.

Since that first discovery three years ago, the WDFW has teamed with the National Park Service to collect samples from live bats in an attempt to understand the spread of the fungus and its associated disease. 

In March 2017, researchers swabbed the wings of 24 bats roosting in the Lewis County section of Mount Rainier National Park. Those tests revealed that four of the bats were infected with the fungus that causes white-nose syndrome, or Pseudogymnoascus destructans. The fungus was found on two little brown bats and two Yuma myotis, although no bats in the colony showed signs of having developed white-nose syndrome.

White-nose syndrome is estimated to have killed millions of bats in eastern North America since 2006. It can wipe out an entire colony during one hibernation period. Scientists are not yet certain if the fungus and disease will have the same severe impact in Washington since western bats do not hibernate in large groups as eastern bats do. 

The fungus typically takes hold on the nose, wings and ears of an infected bat during winter hibernation, resulting in a white, fuzzy appearance. Even when the fungus is not visible to the naked eye, it can still root into deep skin tissues and cause severe damage. 

A press release from the WDFW noted that the bats use the Lewis County roosting area in the spring and summer, but it is unknown where they hide away in the winter months. Scientists have explained that detection of fungal spores in the Lewis County roosting area was of particular importance because it was the first confirmed detection of the fungus in Washington outside the boundaries of King County. Scientists fear the presence of the fungus is more widespread than first thought and that it might be spreading.

While many people harbor unfounded fears of bats, scientists note that they are valuable participants in the ecosystem and even benefit farmers financially through their pollinating and pest-eating services. It is estimated that bats save U.S. farmers more than $3 billion each year in pest control. 

One colony is believed to be able to consume several tons of insects during one growing season alone. In addition to eating bugs that threaten cash crops or human health, they also consume moths and beetles known to be harmful to trees and forests.

The fungus can survive for years in underground environments such as caves and mines. Scientists are currently trying to figure out how long it can persist in other environments that bats frequent, such as cliffs, attics and bridges. It is believed that winter hibernating areas may serve as reservoirs for the fungus and that bats who use, or even visit, infected hibernation spots run the risk of catching or transferring the fungus.

While scientists believe that the fungus is spread primarily from bat-to-bat contact, they warn that humans can also carry fungal spores on clothing, shoes and recreation equipment. In a press release, the WDFW noted that, “Properly decontaminating shoes, clothes and equipment used in areas where bats live is critical to reduce the risk of spreading white-nose syndrome.”

The WDFW cautions that humans should never handle live bats and anyone who is exposed to a bite, scratch or saliva from a dead or live bat should call their local public health department immediately. Additional information on decontaminating outdoors equipment and clothing can be found online at

The WDFW urges people in the area to be cautious around animals, not handle those that appear sick or dead and report all sightings to or by calling (360) 902-2515. The WDFW also warns citizens to be careful as they can unintentionally spread the disease on their clothing, shoes and recreation equipment. 

To learn more about the disease and the national white-nose syndrome response, and to get the most updated decontamination protocols and other guidance documents, visit