May 17, 2016
Quinn Read

The deadly fungal disease responsible for the deaths of millions of bats in the eastern half of the country has made its way to the west coast.

Some of the hardest conservation challenges we face today are threats we cannot see. Disease is one of them.

White-nose syndrome, the fungal disease responsible for decimating bat populations in the eastern United States, recently made its first – and extremely unwelcome – appearance in the Pacific Northwest. A few weeks ago, the U.S. Geological Survey’s Wildlife Health Center confirmed the disease in a little brown bat (Myotis Lucifugus) found by hikers near North Bend, not far from Seattle. How the disease jumped all the way across the country remains a mystery, but now that it’s here, we must act fast to prevent its spread.

Deadly Disease
White-nose syndrome is caused by a fungus (Pseudogymnoascus destructans), and is characterized by the fuzzy white growth that often, but not always, appears on the snouts of infected bats. The fungus invades deep tissues of the wings and skin, causing irreparable damage. When the disease strikes in hibernating populations, infected bats rouse prematurely and, unable to find food, waste crucial fat reserves and starve to death. The fungus can also cause death by damaging wings, interfering with the bat’s ability to regulate body temperature, disrupting its breathing patterns, and causing dehydration.

Bats, © Nancy Heaslip

Since its first appearance in 2006, the disease is estimated to have killed over six million bats in eastern North America and Canada. If it hits during hibernation, it can kill every single bat in a colony. The disease is spread primarily from bat-to-bat contact, but the animals can also become infected wherever fungal spores are present. People can carry these spores on clothing, shoes, or equipment, which is why it is so important that caves where vulnerable bats may be hibernating are kept off limits if there is even the suspicion of white-nose syndrome in the area. In fact, some experts believe that white-nose syndrome may have been brought to Washington by spelunkers traveling from cave to cave without taking measures to decontaminate their clothing or equipment.

Once the disease is detected, experts must take swift action to prevent its spread. But so far, our knowledge on how to treat or prevent the disease is based on bats that live in the east. Bats here don’t typically hibernate in the same kinds of massive colonies as those in the eastern part of the country, so the same practices may not necessarily apply. The fact is, we don’t know how the disease will impact bats in the Pacific Northwest. Right now, it’s hard to tell how far and how fast the disease will spread.

Bats of the Northwest
There are more than 40 species of bats in the United States, and the Pacific Northwest is home to approximately 18 of them, from the silver-haired bat and the western pipistrelle, to the Townsend’s big-eared bat and eight different species of myotis, known as mouse-eared bats. The insects these bats eat and the techniques they use to hunt them vary from species to species. Some, like the western red bat, capture and eat their prey mid-flight. Others, like pallid bats, like to grab crickets and scorpions right off the ground! Spotted bats eat many kinds of insects but prefer moths, while Keen’s myotis prefers spiders – each species is slightly different. Our bats also use every kind of habitat found in the Northwest, from desert to forest, trees to caves. Silver-haired bats like older forests and roost under loose bark, while Canyon bats like to roost in cracks of -you guessed it- canyon walls in arid landscapes.

Pallid bat, © CDFW

Bats play a critical role in Pacific Northwest ecosystems, as well as in human communities and economies. Bats consume a huge amount of insects every day – including some of the most pernicious agricultural pests. Without this natural pest control, we would have an explosion of moths, beetles, flies and mosquitoes. Experts estimate that little brown myotis can eat 600 mosquitos per hour!

If white-nose syndrome continues to spread unchecked, bats may face an extinction crisis. And the ripple effects will touch all of us. A dramatic drop in bat populations – as seen in the Eastern United States – could lead to an explosion of mosquitos and the diseases they carry. It may make us rely even more heavily on chemicals to control insects, which some researchers worry is actually contributing to outbreaks of fungus. It would also have profound consequences for the health of our forests and crops.

Hoary bat, © Daniel Neal

Experts don’t yet know which of the Pacific Northwest’s bat species are susceptible to white-nose syndrome. In the eastern part of the country where the disease is widespread, seven cave hibernating species are afflicted. Two of these – the Little Brown Bat and Big Brown Bat – are also found in the Pacific Northwest. And the verified fungal infection in a Little Brown Bat seems to confirm that this species is vulnerable here as well. Over half of the other bat species found in the Pacific Northwest, and known to roost or hibernate together, could also be at risk.

Little brown bat WNS, © Ryan von LindenNew York Department of Environmental Conservation

Getting Ahead of the Threat
Out east, federal and state agencies have tried to curb the spread of the disease by closing caves and abandoned mines where bats hibernate. They are also issuing decontamination protocols for people who choose to visit the caves. It’s unclear whether any caves will be closed in the Pacific Northwest. In Washington, wildlife officials are conducting surveys and taking samples where the infected bat was discovered. Scientists will use the data to determine how many bats may be infected in our region.

Swabbing a northern long-eared bat, © University of Illinois/Steve Taylor

To confront the new threat of white-nose syndrome in the Pacific Northwest, we’re pressuring the Forest Service to get serious about protecting cave resources – for example, by instituting penalties for people who enter protected or quarantined caves. We will also encourage the Forest Service to create robust guidelines for visitors to caves so they are not unwittingly putting Northwest bats at risk.

There are several things you can do to help. If you think you’ve seen a bat with white-nose syndrome, contact your state Department of Fish and Wildlife immediately, and do not handle the bat. If you live in Washington, the Department of Fish and Wildlife has set up an online reporting form to help.

To prevent the spread of white-nose syndrome, avoid entering areas where bats may be living, including caves and abandoned mines. Likewise, keep your dogs out of areas where bats may be roosting, since they can carry fungal spores to new sites. If you do come into contact with bats or enter an area where bats are roosting, be sure to decontaminate your clothing and equipment immediately. Finally, make sure your elected officials know this issue is important to you, and ask them to support state and federal efforts to confront white-nose syndrome.

Although we don’t get to interact with these unique flying mammals often, we would definitely feel the consequences of a world without bats. We need to do whatever we can to keep that from becoming a reality.


Quinn Read

Quinn Read

Northwest Program Director
Quinn Read directs Defenders of Wildlife’s work to protect imperiled wildlife and their habitats in the Northwest, and oversees field staff in Washington, Oregon, and Idaho.

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