Resurgence of Livestock Threat in South Texas
A significant concern for livestock has emerged once again in South Texas, prompting urgent measures from both state and food safety officials.
On Wednesday, the U.S. Department of Agriculture indicated that the New World screwworm, a harmful, flesh-eating parasite, may have infected areas in South Texas.
According to officials, “These eggs hatch into harmful parasitic larvae, or maggots, that burrow or ‘screw’ into flesh using their sharp mouths.” The USDA has sent a sample to its National Veterinary Services Laboratory in Ames, Iowa, for further analysis.
They are working alongside local partners to keep a close watch on the situation on the ground.
The New World screwworm is known for being a “devastating pest” that preys on the living tissue of warm-blooded animals. Reports show that the larvae resemble common house flies in size.
Documentation from the Texas Animal Health Commission explains that these flies lay eggs in open wounds, which then hatch into parasitic larvae capable of causing severe harm. While New World screwworms typically target domestic animals, they can also affect a range of warm-blooded creatures, including pets and even humans.
Due to their preference for warm, wet environments, a widespread outbreak is deemed unlikely.
On Wednesday evening, Agriculture Secretary Brooke Rollins revealed that testing confirmed the presence of the New World screwworm in a three-week-old calf from Zavala County, Texas. She reassured the public that “Our nation’s food supply is 100% safe,” noting that the situation is contained and does not pose a threat to consumer safety.
She also mentioned that predictions suggested a return of the parasite last year. “All models indicated that NWS would be coming to the United States last summer and early fall. So we are particularly grateful to our partners for their efforts over the past year, which allowed us to better prepare for this moment.”
This preparatory time could prove vital for the already unstable beef industry.
Analysis indicates that as of January 30, 2026, the U.S. beef herd numbered just 86.2 million head, the lowest count in 75 years. Prices for beef have been steadily climbing, showing little sign of reducing, which could worsen if supply further dwindles.
Rollins encouraged farmers to adhere strictly to travel and treatment protocols issued by the Texas Animal Health Commission. A recent report stated preparation for NWS resurgence began over two years ago when a northward migration was detected from Central America.
The U.S. has a successful history of eliminating this parasite in the past, achieving eradication of the indigenous screwworm by 1966 despite facing major outbreaks.
To combat the screwworm, large releases of sterilized flies into affected areas have been employed, sterilized through gamma irradiation prior to release.
In April, the USDA and the U.S. Army Corps of Engineers established an $8.5 million sterile fly production facility at Moore Air Force Base in Edinburg, Texas, aimed to produce impressive numbers of sterile flies weekly to fortify the U.S. strategy against the screwworm.
Rollins characterized the efforts as a comprehensive initiative by the administration.
