Experimental white-nose syndrome treatment tested in Kentucky, Missouri • Story and photos by Kevin Kelly warning to tread cautiously relays to the back of the single-file line like a game of telephone. It is a frigid Friday in late February at Carter Caves State Resort Park and ice covers the steps leading into Saltpeter Cave, rising like stalagmites in spots. Brooke Hines and a crew of fellow biologists clad in bright white coveralls, caving helmets and headlamps slowly make their way into the cave’s belly, where it is a balmy but bearable 49 degrees and the air hangs in a quiet darkness. While others start counting bats dangling upside down from the cave’s ceiling and hairline crevices on its defaced walls, the Kentucky Department of Fish and Wildlife Resources’ bat ecologist veers off the main passageway toward a small room with three others in tow. There’s no silver bullet as of yet to stem the destructive spread of white-nose syndrome in bats, but this room in a cave that derived its name from the potassium nitrate once mined from it for gunpowder may hold a clue. An experimental treatment field tested for the first time this winter in two Kentucky caves and others in Missouri offers a glimmer of hope in the battle against the fungal disease responsible for killing millions of bats across the
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Below: Butterfly cages held the little brown bats before biologists examined them in Saltpeter Cave. Right: Hans Otto weighs a little brown bat contained in a small pouch.
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Going to bat for
bats eastern half of the United States. “The fungus responsible for white-nose syndrome is not native. There is strong evidence to support that people inadvertently introduced it to the United States,” Hines said. “It’s our duty to try to fix it. I don’t want to over-fix it because you can love things to death. But I’m willing to try whatever to save these bats because if we don’t they’re dead anyway. So let’s do what we can
to try to save them.” Researchers have focused on a strain of naturally-occurring bacteria, Rhodococcus rhodochrous, as a possible way to inhibit the fungus without harming the bats. Chris Cornelison, a 29-yearold post doctoral research assistant at Georgia State University, noticed how exposure to the volatile organic compounds (VOCs) emitted by the bacteria suppressed mold growth on a banana. He wondered if it would work with the coldloving fungus behind white-nose syndrome. “We started doing some really basic tests in the lab and the results were just extremely compelling,” Cornelison said. Named for the white fuzz that develops on the muzzle and other parts of infected bats, white-nose syndrome has spread to 25 states and five Canadian provinces since being detected in 2006 near Albany, New York. Kentucky joined the list of affected states when a little brown bat from a Trigg County cave tested positive in 2011. To date, the disease has been confirmed at 78 sites in 22 counties in Kentucky, Hines said. Kentucky has 15 commonly-occurring bat species, including the federally-endangered Virginia big-eared, Indiana and gray Below: Bats were divided into treatment and control groups and placed in separate cages affixed to the cave ceiling.
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bat. About half of those hibernate in caves. The hibernation period typically runs from November through February, and it’s during this time when bats are most susceptible to becoming infected with white-nose syndrome. A bat suppresses its immune system during hibernation and the cold-loving fungus can thrive until the extreme irritation rouses a bat to groom, causing the bat to burn through its precious fat reserves. “We’re seeing population declines of over 85 percent in certain species and we’ve only had white-nose in Kentucky for four years,” Hines said. “As the disease progresses year after year, we probably will have populations of certain species that are extirpated. We won’t see them in caves anymore.” Cornelison and Sybill Amelon, a research biologist with the U.S. Forest Service in Missouri, secured funding from Bat Conservation International and The Nature Conservancy to experiment with the treatment this winter. Saltpeter Cave and a cave on privatelyowned land in Breckenridge County were chosen as the sites for Kentucky’s field testing. There were 120 little brown bats collected between the two sites in November, Hines said. The bats from Saltpeter Cave were divided into treatment and control groups and removed from the cave for 24 hours early in the hibernation period. The treatment group was exposed to the bacterial treatment and both groups were returned to cave
Left: Biologists followed a set protocol when examining the little brown bats in the field. Above: Ultraviolet light reveals wing damage caused by white-nose syndrome. and placed in separate wire mesh cages hung from the cave ceiling. Hines and a team that included Kentucky Fish and Wildlife veterinarian Dr. Iga Stasiak returned to the cave in late February. They carefully removed each bat from its enclosure, then measured, weighed and assessed each for white-nose syndrome. The thin membrane of skin on the wing was held up to an ultraviolet light to reveal any damage caused by the fungus. A swab was applied to each bat’s left wing and muzzle to secure a sample for further testing. The bats were transferred to pop-up mesh butterfly cages then placed in coolers for 24 hours. The cooler for the treatment group contained Petri dishes coated with a paste-like substance infused with the test bacteria. Hines returned the bats to their enclosures the next day. “The reason why we liked this treatment is because it’s contact independent,” Hines said. “You’re not putting anything on the bats. You’re not putting anything in the cave. You’re exposing the bats and then we put them into enclosures.” When this phase of the field study ended in late March, bats with less than 40 percent infection in their wings were released and the rest were taken to Amelon’s lab in Missouri. Cornelison hopes to have a final report on the field trials out this summer.
The muzzles and left wings of the little brown bats were swabbed and sent off for additional testing. “Are we at least diminishing the amount of fungus that’s associated with the animal?” he said. “That can be seen as an indicator of a positive outcome because different researchers have been able to show that the more fungus you have on the bat the more likely it is to end in mortality.” Lab trials at the University of Missouri also are underway to dial-in specific dosages of the bacterial treatment and determine the effects on bats at different stages of the infection. The experimental treatment is not a silver bullet, Cornelison said. If it works, he believes treatment and application options will have to vary by location. “We have a really good collaboration going and we’ll kind of continue to push down this road,” Cornelison said. “It’s to that point where we’ve learned a lot about this disease since it first popped up. It continues to spread. We’re continuing to see bat declines. The entire community is realizing that it’s time for us to move forward and do something to mitigate this disease or else we’re just going to continue to see it spread west, continue to see millions of bats dying off. And we will end up seeing at some point impacts to agriculture or impacts to industry.” n
“It’s our duty to try to fix it. So let’s do what we can to try to save them.” fw.ky.gov
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