A deadly disease is ravaging bat populations in the Eastern and Midwestern United States and several Canadian provinces and if scientists don't find a way to stop it some species could face extinction, experts said.
The disease has been spreading through bat colonies since 2006, after it was first discovered in a cave in Albany, New York. Now scientists and conservationists are trying to prevent it from spreading west and crossing the Mississippi River, as they search for a way to eradicate it altogether. And they may be closing in on how to do that.
Click the audio player to hear more about what scientists are doing:
Scientists now have proof that the disease, called White-Nose Syndrome, is caused by a fungus called Geomyces destructans or the "destroying fungus." Infected bats display a white coating, like talc, on their faces, around their noses or muzzles, and on their wings. The disease mainly strikes during hibernation, often waking the bats in the middle of winter. When they leave their roost to search for food, they can't find it and die, scientists have said.
It's estimated White-Nose Syndrome has already killed more than a million bats and may be pushing some bat species toward extinction. But scientists actually have no specific documentation on the correct number killed and think the number is probably much higher. The fungus has rapidly moved into 19 states and several Canadian provinces since it was first detected.
Bats are an integral part of many ecosystems, eating up to a third of their body weight in insects each night. They help control insect populations in many areas and it is estimated bats save farmers billions of dollars a year in pesticide and insect control expenses.
David Blehert, the head of diagnostic microbiology at the USGS National Wildlife Health Center in Madison, Wisconsin, said White-Nose Syndrome is extremely serious.
"In terms of what we've seen in the northeastern U.S., the level of mortality that we've observed is perhaps unprecedented among mammals, certainly unprecedented among any of the 1,100 species of bats that are known to exist on the planet," Blehert said.
More than 40 of those species call North America home. But not all of them hibernate, many are migratory.
"There's about 25 species of bats in North America that obligately hibernate to survive the winter," Blehert explained to CNN Radio. "We have thus far documented the disease in six of those species, but there are many more species of obligately hibernating bats as you move westward across the country. So worst case scenario is that all hibernating bat species could be affected by this disease."
Wildlife researchers and government scientists, like Blehert, have teamed up with conservationists and cavers. It's a natural partnership because cavers actually go into bat habitats and can see the signs of the disease firsthand. Members of the National Speleological Society, or cave explorers, first discovered the disease. In fact, finding out more about the disease and preventing it from spreading is so important to the group thatÂ Peter Youngbaer was named the White-Nose Syndrome liaison.
"We're directly involved (in helping track WNS) because we own and manage a number of caves as a society," Youngbaer said. "Two that we own in New York state are two of the first four sites where White-Nose appeared."
Youngbaer added: "We had folks come back from a trip to one, which is a cliff entrance with a stream that flows out and people going down to the cave saw dead bats floating in the water. We have another cave that is a gated entrance where it requires you to repel or climb down a ladder some 58 feet to the floor of the entrance room and that entrance room floor was covered with carcasses, about 600 when people went in one day."
That was more than five years ago. WNS has now spread from four caves in New York to western Tennessee and western Kentucky.
Kevin Glen, a member of the Atlanta Chapter of the National Speleological Society which is also known as Dogwood City Grotto said WNS has had an impact on caving.
"The state of Tennessee has actually closed down all the caves on state property. So a lot of really fine caves, including caves that have bats and many that don't even have bats in them at all, have been completely closed down," Glen said. "They just don't want to take a chance on spreading the disease around."
But so far WNS has not crossed the Mississippi River, at least not in a permanent way, yet.
"There were a couple of bats in Missouri in the winter of 2010 that tested positive for the fungus, but didn't show any other signs of the disease," Youngbaer said. "And one bat in Oklahoma in the same year 2010 that tested positive for the fungus. ... And last year, the winter of 2011, there were no signs in either state."
It's unclear exactly how WNS started in the United States. It exists in European bat colonies, but does not kill them, as it does in the U.S.
Some believe a caver traveling in Europe may have unwittingly brought the disease back to the U.S. on his gear leading to cavers spreading the fungus through caves in the northeast. But not all cavers are convinced that's the case. Dogwood City Grotto's Kevin Glenn knows it's possible, but he points out bats could be spreading the disease as well.
"They fly long, long distances. We know that. A lot of the spread of the disease seems to follow migration routes," he said. " I'm not a bat expert, by any means, but I try to keep up with what's going. It's definitely possible bat-to-bat. That's been proven."
Blehert says scientists are working hard to learn as much as possible to try to control the spread of the fungus, but they still have so many questions.
"What we're doing is the more that we can learn about this disease, where it came from, why this fungus is so different from many, many other fungi that are present at bat hibernation sites," Blehert said. "[And] why is this one so different and so deadly?"
If and when scientists can answer those questions, they may be able to put a stop to WNS altogether. Until then the focus remains on trying to contain the disease east of the Mississippi.