Story, map and graphic by Darby Campbell
A new treatment tested at Carter Caves State Park may help bats across the country battle white-nose syndrome.
The treatment called rhodococcus rhodochrous is a naturally occurring bacteria that inhibits fungal growth, explained Brooke Hines, a bat ecologist with Eco-Tech Consultants and one of the researchers who worked at the Carter Caves site. This bacteria has so far helped several bats clear themselves of the fungus.
“They’re important to me because I hate mosquitos and they control the mosquito population,” said Logan Gardner, a park interpreter at Carter Caves, “There’s also a lot we still don’t know about them and their biology. If they were to become extinct it would be devastating because there are still so many things we have to learn from them that could be beneficial to us.”
In fall of 2014, 80 bats were held at Carter Caves for testing. Of those 80 bats, 40 were held in a 72-quart cooler containing petri dishes full of rhodococcus.
“The best part is we didn’t have to spray or rub anything on the bats,” said Hines, “They were exposed to the VOCs coming off the petri dishes.” VOCs are volatile organic compounds, organic chemicals that will evaporate into the air. Once the bats were exposed to these compounds, rhodococcus went to work inhibiting the fungal growth on the infected bats.
The control group of 40 bats was put in another cooler of the same size without the bacteria.
After the bats were released from the coolers, they were taken to predator free enclosures. Twenty bats were placed in each enclosure. Hines and the other researchers returned in February of 2015 to compare the progress of the treated bats and control bats. They returned again a few months later to do a final analysis.
Several healthy bats were released from a testing site in Missouri where researchers had been doing tests in relation to the ones done at Carter Caves.
“For that work last winter we were building off previous research,” said Chris Cornelison, a postdoctoral research assistant with the University of Georgia, and one of the researchers involved in testing rhodococcus at the Missouri site.
“We did some live trials of live bats,” said Cornelison, “Once we were able to demonstrate the bacteria’s success in a lab setting, we took it to the field.”
Some healthy bats were released in March when the bats would have naturally been coming out of hibernation, and some have been retained to watch for any latent negative effects of the bacteria.
“I caution people against using the word cure,” said Hines.
The bats released in Missouri were bats who had been cleared of the fungus, but if they are exposed to the spores that cause white-nose syndrome, they will start to show symptoms of the disease again.
“In my opinion, there is no such thing as a blanket cure for a fungal pathogen. You do not cure it; you manage it,” said Cornelison, “Our goal here has nothing to do with a cure. Our goal is to reduce the mass mortality that is associated with white-nose syndrome.”
The U.S. Geological Survey estimates that bat populations in the northeastern U.S. have been reduced by about 80 percent as a direct result of white-nose syndrome. Carter Caves, in addition to many other parts of northeastern Kentucky, has seen this impact on their bat populations.
“As far as populations go, we’re seeing less of the little brown and tricolor bats,” said Coy Ainsley, park naturalist at Carter Caves, “We are having some reports from guests who are finding dead bats, but we don’t really have as many as we were expecting.”
In order to prevent the spread of white-nose, the park has had to take many preventative measures including the use of biosecurity mats. A biosecurity mat is a large sponge filled with a Lysol and water solution that park guests are required to walk across after every tour in order to kill the white-nose spores on their shoes.
Carter Caves played a small part as hosts of the research.
“We were kind of a liaison for the researchers, as we did not have the man-power or knowledge to conduct the research ourselves,” said Ainsley. Carter Caves allowed the researchers access to the cave and provided anything they needed.
If a treatment for white-nose syndrome were to become readily available, Ainsley said much wouldn’t change about the precautions the park takes.
“I guess what we would do is consult with the Department of Fish and Wildlife to see if we change anything,” said Ainsley
After white-nose was confirmed in Carter Caves, the park started giving guests going on wild crawling tours full-length coveralls to wear into the cave. The coveralls are washed and disinfected after every tour to prevent spores from spreading from cave to cave on guests’ clothing. Ainsley said the park is likely to continue using a full outfit for crawling.
“It would mean happiness and hope,” said Rachel Crum, a park interpreter at Carter Caves, “I would be happy because these little fellas would have a fighting chance at combating white-nose syndrome.”
In her position at Carter Caves, Crum works to educate the general public about the necessity of bats in the ecosystem.
“I would be hopeful because maybe the news of the treatment would help bring awareness of bats’ importance and proper caving etiquette,” said Crum, “Bats play a vital role in their ecosystem, and sadly many aren’t aware of how essential they are.”
Click on the graphic to enlarge.