Cascade Grotto

White-nose Syndrome

White-nose syndrome (WNS) is a fungal disease that has killed millions of bats across North America. As cavers, we’re one of the ways it spreads. Understanding WNS and following decontamination guidance is part of caving responsibly in the Pacific Northwest.

What it is

WNS is caused by Pseudogymnoascus destructans (Pd), a cold-loving fungus that thrives in the same chilly, humid conditions bats need to hibernate. It grows on the bare skin of a hibernating bat’s nose, ears, and wings, producing the fuzzy white growth the disease is named for. The real harm isn’t cosmetic: the infection irritates bats and rouses them repeatedly through the winter, burning the fat reserves they need to survive until insects return in spring. Affected bats can starve, dehydrate, or freeze, and in eastern North America the disease has wiped out more than 90% of bats at some sites.

WNS does not affect humans, pets, or livestock. But people can spread it. The fungus survives in cave sediment for years, and its spores hitch rides on boots, ropes, packs, wetsuits, and clothing – which is exactly how a caver can carry it from one cave to the next.

WNS in Washington

This isn’t a distant problem. Washington’s first case was confirmed in March 2016 in a little brown bat found near North Bend – about 30 miles east of Seattle, and the first occurrence of the disease anywhere in western North America. This stunned researchers, since the WNS outbreak was previously only known to affect the east of the country.

Since then it has continued to spread across the state. The fungus or the disease has now been detected in well over a dozen Washington counties on both sides of the Cascades, with more than 70 confirmed cases across several bat species. In March 2026 WNS was confirmed in neighboring Oregon for the first time. All 15 of Washington’s bat species are insect-eaters that provide natural pest control for forests and farms, so the stakes are both ecological and local.

The bottom line for us: the fungus is present in the caves and karst we visit. Our practices matter.

What this means for cavers

Decontaminate between every cave or mine site. Clean and disinfect all clothing and gear that has been underground before it enters another cave or bat roost (including mines). Follow the current national decontamination protocol — it specifies approved disinfectants and, for submersible gear, a hot-water treatment of 55 °C (140 °F) for 5 minutes or spraying with 50-70% isopropyl alcohol.

2025 Decon Postcard 4in by 6in

Washing is not decontaminating. Running your kit through a normal wash does not kill the fungus. Decontamination means following the protocol.

Better still, keep gear separated by region. Because decon isn’t guaranteed to kill every spore, best practice is to avoid moving gear between distinct cave systems at all where practical, and to avoid moving from a known positive region to one that is unknown or negative. Gear that has been in caves outside the region (including overseas) should be decontaminated before use here, and ideally kept out of sensitive sites.

Please make note that certain regions may have independent criteria (ie. even within Canada, BC has their own rules) around proper decontamination and/or require separate gear which has not been used in another region.

Respect cave closures and access rules. Many caves are closed seasonally during hibernation, or year-round, to protect hibernacula and maternity roosts. On federal land, access often requires registration, permits, and documented adherence to USFWS decontamination protocols. Check current advisories before planning a trip.

Don’t handle bats. Never touch a bat, alive or dead, with bare hands. If you spot bats behaving strangely — flying outside during the day or in freezing weather — leave them alone and report it (see below).

Reporting sick or dead bats

If you find sick, dead, or clustered bats, or bats acting abnormally, report it to the Washington Department of Fish & Wildlife:

Do not handle the bat. Your reports help WDFW track the spread of the disease across the state.

Learn more

Protocols and cave advisories are updated regularly. Always check the current guidance at whitenosesyndrome.org before a trip.

Clean and decontaminate gear following the guidelines published by www.WhiteNoseSyndrome.org, quick reference guides below. Be sure to follow instructions on the cleaning products and take care when cleaning safety gear.

Areas with confirmed or suspected white-nose Syndrome occurrences. Source: https://sciencebase.usgs.gov/nabat/#/wns/map

Learn about White-nose syndrome in Washington State here: Washington Department of Fish and Wildlife

Timeline of WNS in Washington State:

Note: Some bat species are affected by white-nose syndrome while others may only carry the fungus that causes white-nose syndrome (Pseudogmynoascus destructans [Pd]), and not show any symptoms of the disease.

April 2019

March 2019

May 2018

April 2018

March 2018

January 2018

July 2017

May 2017

April 2017

July 2016

March 2016

*Source:
https://wdfw.wa.gov/species-habitats/diseases/bat-white-nose#