For the first time, Oregon wildlife officials have confirmed the presence of white-nose syndrome in bats within the state. The deadly fungal disease, which has decimated bat populations across North America, was detected in bats found in Columbia and Benton counties, the Oregon Department of Fish and Wildlife (ODFW) announced on March 18, 2026. This discovery marks a significant concern for the state’s bat populations and the broader ecosystem they support.
White-nose syndrome isn’t a threat to humans or domestic animals, but it poses a grave danger to bats. The disease is caused by the fungus Pseudogymnoascus destructans, which disrupts bats’ hibernation, leading to dehydration, starvation, and death. Since its initial detection in New York in 2007, white-nose syndrome has spread to at least 30 states, resulting in the estimated deaths of 6.7 million bats, according to ODFW.
The recent diagnoses in Oregon came after laboratory tests conducted by the National Wildlife Health Center. Six Yuma myotis bats from Columbia County and one little brown myotis bat from Benton County tested positive for the disease. These bats were found deceased in residential areas during late winter and reported to ODFW, prompting further investigation. This finding follows the 2025 detection of the Pseudogymnoascus destructans fungus in bat guano collected at a roost in Clatsop County, signaling the fungus’s prior presence in the state.
How White-Nose Syndrome Impacts Bats
The impact of white-nose syndrome on bat populations is severe. During hibernation, the fungus grows on the bats’ skin, causing irritation and damage. This prompts the bats to wake up more frequently to groom, depleting their critical energy reserves needed to survive the winter months. Affected bats often emerge from their hibernation sites prematurely, appearing weak or dying from exhaustion. Both the Yuma myotis and the little brown myotis, the species affected in Oregon, are small insectivorous bats common throughout the state.
The spread of the fungus primarily occurs through bat-to-bat contact, particularly during hibernation. While the disease doesn’t pose a risk to humans or pets, it can be inadvertently spread by people through contaminated clothing, gear, or equipment used in or near caves or roosting sites. This highlights the importance of following decontamination protocols for anyone exploring bat habitats.
Oregon’s Response and Ongoing Monitoring
ODFW is actively coordinating with state, local, and federal partners to assess the full extent of the impact on Oregon’s bat populations. This collaborative effort will focus on monitoring the spread of the disease, understanding its effects on different bat species, and developing strategies to mitigate its impact. The agency is urging the public to report any sightings of sick or deceased bats to aid track the disease’s progression.
The detection of the fungus in Clatsop County in 2025, as reported by Oregon Public Broadcasting, served as an early warning sign. Now, with confirmed cases of the disease itself, Oregon joins the growing list of states grappling with this ecological crisis.
Why Bat Populations Matter
Bats play a crucial role in maintaining healthy ecosystems. As insectivores, they consume vast quantities of insects, including agricultural pests, helping to control populations and reduce the need for pesticides. The loss of bat populations due to white-nose syndrome could have significant economic and ecological consequences. A decline in bat numbers could lead to increased crop damage, higher pesticide use, and disruptions in natural pollination processes.
The Oregon Department of Fish and Wildlife emphasizes that the situation is evolving. Further research and monitoring are essential to understand the long-term effects of white-nose syndrome on Oregon’s bat populations and to develop effective conservation strategies. ODFW will continue to provide updates as new information becomes available.
Disclaimer: This article provides information about a wildlife health issue and is intended for general knowledge and informational purposes only, and does not constitute medical or veterinary advice.
The ODFW will continue to work with partners to monitor the situation and assess the impact on Oregon’s bat populations. Updates will be provided as they become available. Share this information with others and help protect Oregon’s vital bat populations.
