A disease that is killing millions of bug-eating bats has shown up for the first time in Richland County, indicating the disorder could have broader impacts on the winged mammals than previously known.
Recent laboratory tests confirmed white-nose syndrome in a bat from a site in the Columbia-area, according to the S.C. Department of Natural Resources.
The discovery is significant because it indicates the possible spread of the disease away from the mountains and into other parts of South Carolina. That’s a concern, not only as a threat to the species itself, but because bats are natural exterminators.
Bats eat many bugs, such as wasps and mosquitoes that commonly are considered pests to humans.
“They do provide a very important role for insect control,’’ DNR biologist Mary Bunch said. “In some cave systems, they are the pinnacle species in there.’’
Of the 1 million little brown bats killed by white-nose syndrome nationally, it is estimated they could have eaten up to 1,320 metric tons of insects in a year, according to the DNR.
The disease, which is not a threat to humans, is deadly to bats that hibernate during the winter. The dormant period of the bats gives the fungus time to grow and sicken the animals. South Carolina has seven species that hibernate, including the little brown bat, the big brown bat and the tri-colored bat.
Scientists say the bat found in Richland County was a tri-colored bat, a small animal that is one of the most susceptible to the disease because the species tends to hibernate the longest.
The DNR does not know where in Richland County the bat came from. It was shipped to a laboratory in Georgia after testing negative for rabies. By practice, the Department of Health and Environmental Control will forward non-rabid bats for testing for white-nose syndrome. DHEC referred questions back to the DNR. Bats typically roost in caves but also in trees and old buildings.
Researchers identified white-nose syndrome last year in bats that live in the southern Appalachians northwest of Greenville. Bunch said DNR officials are hopeful that milder winters on the coast will prevent the disease from spreading that far, but she there’s no way to know how the animals will be affected.
“We need to act like many of the true hibernating bats in the entire state are infected," Bunch said. "We can't assume that bats in our coastal region aren't affected anymore.’’
Some bat populations have declined for various reasons, but the threat of white-nose intensifies concerns. Bunch said populations of tri-colored bats studied in one Oconee County cave dropped from about 400 two years ago to little more than 100 this year.
First detected in New York seven years ago, white-nose syndrome has spread to 25 states. Until 2013, it had not been verified in South Carolina. Bunch said the disease has been confined to the East. Precautions have been taken to prevent outdoors people from unwittingly spreading the disease.