Deadly Disease Spreading in Texas Bats
During recent cave surveys and routine monitoring, biologists found evidence of white-nose syndrome (WNS) in tricolored bats — the first known case of WNS in tricolored bats in Texas and the southernmost confirmation of WNS in this species.
The fungus that causes the development of white-nose syndrome, P. destructans, was also present on three new species of bats in Texas that had previously not been tested, or had not previously tested positive, for the fungus — fringed myotis, long-legged myotis and canyon bats.
This is the first time that canyon bats have tested positive for the fungus anywhere in the country.
Since several bat species are known carriers of the fungus, the presence of P. destructans does not mean a bat is positive for WNS. White-nose syndrome has killed millions of hibernating bats in the eastern parts of the United States, raising national concern.
P. destructans is a cold-adapted fungus that occurs in hibernating bat species and is not a risk to people or other wildlife. Other species of bats that do not hibernate, such as the Mexican free-tailed bat, can carry P. destructans but do not develop WNS. Although P. destructans fungus has been present on bats in Texas since 2017, the first confirmed case of a P. destructans infection resulting in WNS in Texas occurred in 2020, when dozens of cave myotis were found dead in Central Texas.
Since P. destructans is categorized as a cold-loving fungus, the impact of WNS on southern populations of susceptible species has been a topic of significant speculation.
“Some researchers hypothesized that populations in warmer climates may not develop WNS, or may not experience the same level of impact, as their more northern counterparts,” says Jonah Evans, non-game and rare species program leader for the Texas Parks and Wildlife Department (TPWD). “Unfortunately, with the development of WNS in cave myotis in Central Texas in 2020, and these most recent reports in tricolored bats, hopes that WNS may not develop or significantly impact some WNS-affected species in southern regions have been upended. Nevertheless, while the detections are a concerning development, the severity of the disease in this region and for this species remains unknown and requires continued surveillance.”
The development of P. destructans in canyon bats, however, holds significant implications for the spread of WNS across the species' range, which extends across a vast portion of the western United States, says Samantha Leivers, state bat specialist with TPWD.
“Due to our limited knowledge of canyon bat ecology and behavior in Texas, it is unknown whether canyon bats will act only as a carrier of P. destructans, or whether they may be affected by WNS,” Leivers says. “Regardless, this development certainly alters our understanding of the spread of P. destructans and the species that may be affected by WNS.”
