Llano County makes screwworm disaster declaration
The New World screwworm has been detected in Gillespie County, raising the alarm for livestock producers, pet owners, and wildlife populations in the Hill Country. United States Department of Agriculture photos
Llano County declared a local state of disaster on Monday, June 15, regarding the county’s close proximity to the spreading threat of the New World screwworm outbreak.
A confirmed New World screwworm case documented on Monday, June 8, in Gillespie County put southwest Llano County within the “Adjacent Surveillance Zone” established by the Texas Animal Health Commission to monitor the screwworm outbreak.
According to a media release issued by Llano County on Monday, this declaration will remain in effect until June 22, when the Llano County Commissioners Court next convenes, and the court will determine whether or not to renew the declaration at that time.
The declaration of a local disaster activates Llano County’s emergency response resources and gives official authorization to local leaders to pursue assistance from other agencies and government bodies at the state and federal level.
Llano County residents with additional questions or concerns regarding the screwworm and local response should contact the Llano County AgriLife Extension Office at 325-247-5159.
An updated TAHC map released on Wednesday, June 10, shows southwest Llano County as within the “Adjacent Surveillance Zone” surrounding the “Infested Zone” emanating from western Gillespie County.
Background on the worm
The screwworm is the larval form of the New World screwworm fly. It is a flesh-eating parasite that wreaked havoc on Texas livestock, pets, and wildlife for decades before being effectively eradicated in the United States by the 1980s.
A resurgence of the bug was detected in Central America in 2023, moving steadily northward, with state and federal officials warning in 2025 of a possible U.S. outbreak.
The first confirmed infection documented in the recent wave within U.S. borders was in Zavala County, TX, on June 3.
Texas has been on high alert since the Zavala County case was detected. On Monday, June 8, Governor Greg Abbott activated the Texas State Emergency Operations Center to “Level II,” mobilizing state resources and agencies to combat the screwworm outbreak.
“I have activated the full use of all state resources to respond to the New World screwworm threat,” Governor Abbott wrote in a June 8 media release. “The protection of our ranchers, livestock producers, deer breeders, and the Texas economy from this pest is a top priority.”
Fly/worm life cycle and impacts
The concern about the worm centers on its ability to quickly harm or even kill animals if left untreated.
According to a research evaluation from the Texas A&M Agrilife Extension on the New World screwworm, female flies are attracted to fresh, open wounds on warm-blooded animals. A wound as small as a thorn scratch or a tick bite is enough to draw them in.
Of special concern are the umbilical cord attachment points on newborn livestock, castration wounds, branding wounds, shearing wounds, dehorning wounds, or other wounds caused in regular ranching or agricultural work.
Female flies lay 100-300 eggs on the perimeter of a wound and within 24 hours the eggs hatch and begin to feed on living or dead flesh in the area.
Within one to two weeks, the worms grow, feeding on their host, consuming a large amount of flesh.
“Untreated screwworm infestations can be fatal,” wrote Texas A&M Entomologist Bart Drees. “The larvae will continue to feed on the animal and will eventually eat the host alive.”
Drees wrote that treating wounds immediately was the best control measure for screwworm infestations.
“Any animal with a severe wound should not be left untreated or out in the pasture unprotected,” he said.
dakota@thepicayune.com