Fran Hutchins, Bracken Cave Preserve Director, watches the bats fly away from Bracken Cave for the evening to feed.
Fran Hutchins, Bracken Cave Preserve Director, watches bats fly from Bracken Cave to feed. Credit: Bonnie Arbittier / San Antonio Report

A fungal disease that has devastated bat populations across the eastern half of the United States has spread as far south as Kendall County, Texas Parks and Wildlife Department officials said.

Biologists have identified the fungus that causes white-nose syndrome spreading south from previously confirmed sites in the Texas Panhandle, including one site in Foard County, one site in Wheeler County, two sites in Blanco County, and sites in Kendall County, which borders Bexar County to the north, according to a Texas Parks and Wildlife Wednesday news release.

Between December and March, biologists with Bat Conservation International and Texas A&M University used skin swabs to detect the fungus on cave bats, tri-colored bats, Townsend’s big-eared bats, and on a single a Mexican free-tailed bat, officials said.

None of the bats showed signs of white-nose syndrome, in which the fungus spreads across the bat’s body and appears as white growth on its muzzle and wings. That typically takes a few years after infection to develop, according to Texas Parks and Wildlife.

Never before has the fungus, called Pseudogymnoascus destructans, been found on a Mexican free-tailed bat, the species that draws crowds to Bexar County’s Bracken Cave in the summer to watch their nightly emergence.

Since first appearing in New York in 2007, the fungus has devastated bat populations by rousing them from winter hibernation. They then leave their hibernating places in search of insects and – finding no food – often starve.

“While Mexican free-tailed bats are not expected to be susceptible to [white nose syndrome], we are concerned because they migrate in large numbers and may help spread the disease further into the western United States or into Mexico,” said Jonah Evans, a Texas Parks and Wildlife mammalogist who oversees the agency’s bat program, in a prepared statement.

Biologists detected the fungus on the Mexican free-tailed bat at Old Tunnel State Park in Kendall County. That county is the southernmost county in the U.S. where the fungus has been confirmed, Evans said.

Scientists believe the fungus is primarily spread from bat to bat, though it can also hitch a ride on human visitors and spread to other caves, according to the U.S. Fish and Wildlife Service.

Bat experts are urging would-be cavers to avoid visiting known bat hibernating spots in winter months and to thoroughly clean and disinfect clothing and gear after visiting caves.

Brendan Gibbons is a former senior reporter at the San Antonio Report. He is an environmental journalist for Oil & Gas Watch.