This Medicine-Misting Bat Cave ‘Air Freshener’ Could Ward Off a Deadly Disease

White nose syndrome has killed an estimated 6 million bats in North America, which are an important part of our food system.

Jul 28 2016, 3:00pm

Image: USFWS/Ann Froschauer

Microbiologist Chris Cornelison likes to mention tequila when trying to convince apathetic individuals to care about bat conservation.

"Bats are the exclusive pollinators of agave," Cornelison, who works at Georgia State University, told me over the phone. "It's one thing people don't know but I use it all the time to generate public support for bats."

Bat numbers are currently under threat by a deadly disease, but scientists might finally have a solution to save them: an air freshener-inspired device that spritzes disease-fighting mist inside bat caves.

Cornelison studies white nose syndrome, a fungal infection that's been decimating many species of bats up and down the east coast of North America for a decade. White nose syndrome has killed an estimated 6 million bats in the US and Canada, whittling some bat colonies down to just 10 percent of their historic numbers.

Though the bats that pollinate plants like tequila-producing agave haven't yet been affected, Cornelison told me that's a scenario they're working to avoid. And the scourge has affected many species of insect-eating bats, which serve as a natural insecticide, indirectly protecting crops—some researchers have estimated they save the US agricultural industry as much as $23 billion a year by eating up crop-destroying pests.

Whether to protect tequila or our food crops, scientists like Cornelison are eager to find a way to curb white nose syndrome. One way they're hoping to do that is by using a bathroom air freshener-inspired device to pump fungus-neutralizing spray into a cave full of bats.

Little brown bat with white-nose syndrome Image: Marvin Moriarty/USFWS

Cornelison and his colleagues have developed a mixture of naturally-occurring compounds that have been shown in lab tests to be very effective at warding off Pseudogymnoascus destructans, the fungal pathogen that causes white nose syndrome. To test if it will help prevent fungal growth on not just petri dishes, but also bats, they needed a way to disperse this compound in a bat environment: a cave where they hibernate.

"We came across these odor-sanitizing dispensers that you've probably seen at a hotel or the gym: They go off on a timer, there's a burst of mist, and a few minutes later you smell lavender or vanilla bean," Cornelison told me. "It just so happens that, in most cases, for the human nose to detect these scents they need to reach about 10 parts per million. That was really similar to the level of concentration needed to inhibit the fungus."

A graduate student then used that proof-of-concept to design a device that will spread the fungus-curbing compound using an adapted medical nebulizer:

A prototype of the device to be installed in the cave this fall. The complete system includes batteries, controller, and nebulizer compressor housed in a weatherproof case Image: Kyle Gabriel/Georgia State University

Working alongside the US Fish and Wildlife Service and Georgia's Department of Natural Resources, Cornelison and the team have chosen a site to test out this treatment: a manmade cave in Northeast Georgia. Originally intended to be a railway tunnel, the cave flooded and was abandoned midway through construction in the 1850s. Over the years, Black Diamond Tunnel turned into the largest hibernation spot for tricolored bats in the state, but recently white nose syndrome has cut that population from 5,500 to just over 200.

Aside from being a white nose syndrome hotspot, the cave is ideal because it's a dead end, with no side tunnels, and has a uniform construction, making it easy to take measurements like air volume. Now, they're just waiting for the bats, which have yet to begin hibernation.

"Year to year, bats in Georgia will begin using those sites anywhere from late September in a cold year to mid-November in a warm year," Cornelison said. "As soon as we see large numbers of bats utilizing that site, that's when we begin deploying."