White-nose syndrome detected in bats for first time in Oregon

SALEM, Ore.— White-nose syndrome (WNS) in bats has been detected for the first time in Oregon in Columbia and Benton counties. White-nose syndrome is caused by an infection with the fungus Pseudogymnoascus destructans that disrupts hibernation, causing early winter emergence, dehydration and starvation.

This finding follows the 2025 detection of Pseudogymnoascus destructans in bat guano collected at a roost in Clatsop County. Bats in Oregon have now tested positive for the fungus and have shown signs of the disease.

In March 2026, laboratory tests by the National Wildlife Health Center diagnosed white-nose syndrome disease in six Yuma myotis from Columbia County and one little brown myotis from Benton County. Both species are small insectivorous bats that are found throughout Oregon. The bats were found deceased in residential areas in late winter and reported to ODFW.

How does white-nose syndrome affect bats?

White-nose syndrome has killed millions of bats in North America since its detection in New York in 2007 and continues to spread. At least 30 states have detected the disease, and others have detected the fungus but no disease. The fungus spreads primarily through bat-to-bat contact and infects bats during hibernation. White-nose syndrome does not cause illness in humans or domestic animals, but it can be inadvertently spread through contaminated clothing, gear, and equipment after recreating in or near caves or visiting sites like summer roosts or mines.

During hibernation the fungus grows on the bat's skin causing damage and irritation. Bats wake up frequently to groom it off which uses up critical energy needed to last through hibernation. Bats with WNS sometimes leave their winter sites early and head to spring roosts where they may be found weak or dead from WNS.