Bat Killer Confirmed

The Geomyces destructans fungus causes deadly white-nose syndrome in bats

A little brown bat with symptoms of white-nose syndrome
A little brown bat with symptoms of white-nose syndrome Greg Thompson/USFWS

Earlier this year, Smithsonian magazine published a story by Michelle Nijhuis about white-nose syndrome, the disease that is devastating U.S. bat colonies in catastrophic numbers:

The disease was discovered in early 2007, when bats in upstate New York started behaving oddly. Instead of hibernating through the winter, they flew into neighborhoods during the day, wandering dangerously far from their caves. “There would be three feet of snow and it would be 20 degrees—not bat-flying weather—and you’d see bats flying out and taking off into the distance,” says Al Hicks, then a wildlife biologist for the New York State Department of Environmental Conservation. “You’d know every darn one of them was going to die. It was awful.”

Later that winter, during a routine cave survey, New York State biologists found thousands of dead bats in a limestone cave near Albany, many encrusted with a strange white fuzz. During the winters that followed, dead bats piled up in caves throughout the Northeast. The scientists would emerge filthy and saddened, with bat bones—each as thin and flexible as a pine needle—wedged into their boot treads.

By the end of 2008, wildlife-disease researchers had identified the fuzz as a fungus new to North America. Today the fungus has spread to 19 states and 4 Canadian provinces, and infected nine bat species, including the endangered Indiana and gray bats. A 2010 study in the journal Science predicted that the little brown bat—once one of the most common bat species in North America—may go extinct in the eastern United States within 16 years.

When talking about the cause of the disease, we (the writer and editors) were careful in our language, saying only that it appeared to be caused by a fungus, Geomyces destructans. The scientists studying the growing disaster couldn’t definitively link the two.

Now they can. A new study, published this week by Nature, has confirmed the scientists’ suspicions. In the new study, the researchers exposed 29 little brown bats hibernating in the lab to G. destructans spores; all the bats developed the symptoms of white-nose syndrome (white fungus growing on the muzzles and wings). They also exposed 18 additional healthy bats to the fungus by housing them with sick bats; 16 of the 18 developed the disease, confirming that it can be transmitted from bat to bat. “The fungus alone is sufficient to recreate all the pathology diagnostic for the disease,” the study’s senior author, David Blehert, a microbiologist at the National Wildlife Health Center in Madison, Wisconsin, told Nature.

Scientists are continuing to search for a way to treat infected bats and halt the spread of the disease. Their best weapons right now, however, are fairly crude and aimed at preventing the further spread of the fungus: cleaning shoes and gear after people have been in caves and closing off some caves altogether. But with the winter hibernation season closing in, it’s sad to know that more bats are sure to die.

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