Extinction Countdown

Extinction Countdown

News and research about endangered species from around the world

Bat-Killing Fungus Now Found in 25 U.S. States


WNS little brown batThe news for bats in the U.S. keeps getting worse. Last week conservation officials announced that the bat-killing white-nose syndrome (WNS) has been found in Michigan and Wisconsin. The disease, spread by the fungus Pseudogymnoascus destructans (Pd), has now reached 25 states and five Canadian provinces since it first turned up in New York State in 2006. Afflicted bat populations often have mortality rates approaching 100 percent once they become infected. More than six million bats have died since the disease emerged.

There is no treatment for the fungus or disease. The fungus thrives in cold, damp caves that are impossible to decontaminate.

According to the Michigan Department of Natural Resources, WNS has been found in three of Michigan's 83 counties: Alpena, Dickinson and Mackinac. "These are the first confirmed WNS cases in Michigan," Dan O'Brien, DNR wildlife veterinarian, said in a press release. "Even though we've known this disease was coming, it is a disappointing day. We will now shift gears and try to stop the spread." The counties are not contiguous, so it seems likely that the fungus is also present in other locations.

So far, Wisconsin's WNS cases appear to be much more limited; the disease has only been found in a single mine in Grant County, where 2 percent of the bats showed signs of the disease. Again, the discovery of the disease in Wisconsin was not unexpected. "The discovery is not a surprise but it's a sad day for Wisconsin," Erin Crain, director of the Wisconsin Department of Natural Resources Natural Heritage Conservation Program, said in another press release. "With great cooperation from mine and cave owners, we took aggressive steps to prevent human spread of the disease to Wisconsin, and we think those steps helped delay its arrival by several years, allowing more time for research and to learn from other states' experiences... We face the loss of multiple bat species and the benefits they provide to our ecosystems and our people."

Both states have set up Web sites (Michigan, Wisconsin) where citizens can report any dead or infected bats they encounter.

The Pd fungus has been found in an additional three states (Iowa, Minnesota and Oklahoma), but WNS mortalities have not yet been reported there.

Main photo: A little brown bat (Myotis lucifugus) from Avery County, N.C., with fungus on its nose, by Gabrielle Graeter/NCWRC. WNS spread map via

The views expressed are those of the author and are not necessarily those of Scientific American.

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