Deciphering Mystery Of Bat-Killing Fungus

A scientist examines a bat near Boston, Mass. Biologists are struggling to understand a fungus called white nose syndrome that has killed more than a million bats over just three winters.
When evidence of a disease that has decimated bat populations in the Northeast turned up on Kentucky's doorstep, Hazel Barton felt obligated as an avid caver to offer her help.

The third-floor lab at Northern Kentucky University's Natural Science Center where she teaches and guides research is one of just a few in the world that studies the types of caves that bats find hospitable for hibernating.

"We're federally funded to do a lot of cave microbiology, so this is just a portion of what we work on," said Barton, the Ashland Endowed Professor of Integrative Science at NKU. "It's taking up a lot more time because it's just such an emergency right now and we've really shifted a lot of time and effort."

An estimated 1 million bats have succumbed to "white-nose syndrome" since its discovery three years ago in New York. Named after the fungus that develops on the snouts, ears and wings of affected bats, it has been found at hibernation sites in nine states, including recently in western Virginia and West Virginia.

Tennessee and Kentucky are being monitored closely.

"All eyes are on Kentucky and Tennessee and other states around that region for what's going to be happening in the next few months because I anticipate that white-nose will spread," said Jeremy Coleman, the national white-nose syndrome coordinator for the U.S. Fish and Wildlife Service.

Barton is working with research technician Marcelo Kramer and three NKU students to identify compounds that stop the fungus associated with white-nose syndrome. In October, it was selected for one of six federal grants.

"It's kind of like old-school microbiology," Barton said.

"We're looking for a magic bullet that just kills Geomyces destructans and doesn't harm anything else."

There are 45 species of bats in North America and seven of those that live in the area impacted by white-nose syndrome are being wiped out by it, Barton said. Kentucky is home to more than a dozen bat species. The fungus grows into the bats' skin, causing extreme irritation that arouses them from their slumber to groom. The activity burns up fat reserves, said Brooke Slack, bat biologist for the Kentucky Department of Fish and Wildlife Resources, and the bats ultimately starve to death.

"What's believed to be happening to these bats, they're emerging early in the winter and they're flying out into 20-degree, snow-on-the-ground landscape with no food and they're dying very quickly either of freezing or of low fat reserves," said Slack.

Bats fill a unique ecological niche by helping control the insects that fly at night. The typical diet of a bat includes moths, beetles and water-born insects like mosquitoes. A reduced bat population will be noticed.

"Economically speaking, for people, it's going to be kind of a ripple effect," Slack said, noting that one impact would be higher produce prices due to an increased use of agriculture pesticides.

The U.S. Fish and Wildlife Service has recommended a moratorium on caving activities in states where white-nose syndrome has been documented and states adjacent to those.

The leap from New York to West Virginia suggests cavers may be contributing to the spread of white-nose syndrome. To that end, Barton conducted research that aided in the development of a decontamination protocol for cavers and their equipment. The research found that certain cleaning agents are effective at killing the fungal spores associated with white-nose syndrome.

A refrigerator in Barton's lab is stocked with petri dishes containing fungi collected by swabbing bats and cave surfaces.

"We're looking for compounds that are naturally found on bats that are known to be antifungal," Barton said. "We're looking for compounds that are made by micro-organisms that actually live in the caves that are anti-fungal. We're looking at compounds that are made by plants that they store in their roots that are anti-fungal."

A couple of the compounds have found to be effective on fungi, she said.

"We're actually doing field studies with these to see if we can use those to protect the bats," Barton said. "We don't want to make things worse. We want to make things better."