Photograph courtesy Alan Hicks
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Hibernating little brown bats infected with white-nose syndrome (file photo).
Photograph courtesy Alan Hicks

Bats May Be Wiped Out by Fungus in U.S. Northeast

"Distressing" disease spreading throughout U.S. and Canada, expert says.

One of North America's most common bats will go extinct in the northeastern U.S. within two decades if a deadly disease continues to spread unchecked, scientists warn in a new study. And other bat species—including the rare Indiana bat—may soon follow suit.

White-nose syndrome, first found in 2007 in a New York cave, is named for the white, cold-loving fungus that appears on afflicted bats' noses, wings, and ears.

The condition makes bats restless and disturbs their winter hibernation. Instead of sleeping peacefully, infected bats burn up their fat reserves, causing them to die at a staggering rate—almost 75 percent a year in affected colonies, research shows.

So far the syndrome is known to infect nine hibernating bat species, including the widespread and well-studied little brown bat. (Listen to bat calls.)

Biologist Winifred Frick and colleagues collected bat population data gathered over the past three decades from nearly two dozen hibernation sites in five states, and ran the data through population models.

Their analysis showed that little brown bat populations crashed when white-nose syndrome appeared in North America—perhaps introduced from Europe or another distant locale.

"We also found that if mortality continues the way we've seen it, the regional population of this bat ... will basically be gone from the landscape in 16 to 20 years," said Frick, of Boston University and the University of California, Santa Cruz.

Bat Fungus Becoming a "Continental" Problem

During 2010 infected bats were found as far south and west as Tennessee and Oklahoma (see a U.S. map). The fungus has also spread north to the Canadian provinces of Quebec and Ontario.

"This is quickly becoming a continental scale problem," Frick said. "We're not surprised by this, but we are distressed by it."

And, as the ailment gets a foothold in more places, it's impacting more bat species.

"We chose little brown [bats] because we had really good data, and because they were a very common and abundant species," Frick explained.

"But it's reasonable to assume that other hibernating species will face similar dangers, because the fungus grows in the hibernation sites. And some of those species, like the Indiana bat, are already endangered species."

There is no cure for the syndrome, though scientists are searching for ways to combat the disease.

Bat Extinctions Could Affect People, Too

Though the situation looks bleak for bats, humans also have cause for concern, Frick said. That's because the flying mammals eat a lot of insects—such as mosquitoes—that damage crops, spread disease, and generally pester people.

"All the bats affected are insect predators," Frick explained, "and an individual bat can eat its own body weight in insects each night."

The bat-fungus research will be published in the August 6 issue of the journal Science.