A deadly “flesh‑eating” livestock parasite just breached Texas for the first time in nearly 60 years, and the way it got here raises serious questions about border security and America’s food independence.
Story Snapshot
- A New World screwworm infestation was confirmed in a three-week-old calf in Zavala County, Texas, the first U.S. case since the 1960s.
- Experts warn the parasite can eat living flesh of cattle, wildlife, pets, and even humans, making early detection and containment critical.
- USDA officials insist the single case is “fully contained,” but acknowledge years of northward spread through Central America and Mexico.
- Trump-era agriculture leaders are tying the threat’s return to prior open-border policies and illicit cross-border cattle movements.
Confirmed Texas Case Ends 60 Years Without Screwworm
The United States Department of Agriculture confirmed that New World screwworm larvae were found in the umbilical area of a three-week-old calf near La Pryor in Zavala County, South Texas, ending six decades without a domestic case.[1][3] The sample was tested and confirmed at the National Veterinary Services Laboratories in Ames, Iowa, which serve as the federal government’s top diagnostic facility for serious animal diseases.[1] Officials say no additional animals have tested positive so far, underscoring both the urgency and early-stage nature of the incident.[1][3]
Texas A&M University describes the New World screwworm as a parasitic fly whose females lay eggs in open wounds of living warm-blooded animals, where larvae hatch and then feed on living tissue rather than dead flesh.[1] That gruesome behavior can lead to severe, rapidly expanding wounds, secondary infections, and death if cases go untreated.[1] State wildlife officials warn that the pest can attack cattle, wildlife, pets, and even people, especially newborns or animals with fresh injuries.
How Dangerous The Screwworm Is For Ranchers, Pets, And People
Livestock specialists stress that screwworm infestations are not a theoretical problem for ranchers; they can devastate herds by turning routine cuts, branding wounds, or birthing injuries into life-threatening infestations.[1] Texas A&M notes that since 2023 the parasite has reestablished itself north of the Panama Canal and moved as far north as Veracruz, Mexico, where more than 6,500 cases were reported in 2024 alone.[1] That northward march put the parasite within striking distance of the U.S. border before this Texas confirmation.[1][3]
Texas Farm Bureau guidance, written for producers and now suddenly very timely, emphasizes that early detection is critical because larvae multiply quickly and can spread across tissue if not treated promptly.[2] Ranchers are instructed to immediately isolate any animal showing suspicious wounds, contact a veterinarian, and report the case to the Texas Animal Health Commission without delay.[2] Veterinarians, in turn, are legally required to collect larvae and submit them to the United States Department of Agriculture National Veterinary Services Laboratory for confirmation.[1][2] That mandatory federal lab pathway is what turned the La Pryor case from a local concern into a nationally watched biosecurity event.[1][3]
Federal Response: Containment, Not Panic—And No Immediate Food-Safety Risk
United States Secretary of Agriculture Brooke Rollins told reporters the Texas case is “fully contained” and that surrounding cattle remain under close watch but are not automatically infected.[2][3] Federal and state teams have launched intensified surveillance and trapping around the affected area, and the United States has deployed thousands of detection traps along the southern tier since early 2025, yielding tens of thousands of samples before this first positive result.[1][2] Rollins has also emphasized that New World screwworm does not infest processed meat, fruits, or vegetables, so the current threat is to animal health and producer economics, not the safety of meat already in grocery stores.[1]
The immediate containment strategy leans heavily on the “sterile insect technique,” which involves releasing large numbers of sterilized male screwworm flies so that wild females produce no viable offspring.[2] Agriculture officials describe this as one of the most effective and environmentally friendly pest-control tools ever developed, a method that helped eradicate screwworm from the United States in the 1960s.[2][1] Mexico and Panama are assisting with sterile-fly production, and plans are underway for a dedicated United States production facility in South Texas that will expand capacity by 2027.[2] Movement controls in the local zone, along with education for ranchers and veterinarians, round out the current response.[1][2]
Border Security, Prior Policy Failures, And What Comes Next
Rollins has publicly linked the parasite’s northward push to what she called “open-border policies of the last administration” and related illicit cattle movements that undercut biosecurity.[1] That charge reflects a longstanding concern among many conservatives that weak enforcement at the southern border does not just affect crime and culture, but also allows unchecked movement of animals and diseases that threaten American producers.[1][3] Industry outlets report that Texas producers have been warned for months to stay on alert as New World screwworm detections moved north through Mexico, including recent cases in the border state of Tamaulipas.[3]
A case of New World screwworm has been confirmed in the umbilicus of a 3-week-old calf in Zavala County, Texas by the @usda_aphis. https://t.co/ZtUXyXwAeV
— AVMA (American Veterinary Medical Association) (@AVMAvets) June 4, 2026
For now, national cattle leaders are urging vigilance without panic, noting that a single, contained case does not equal a statewide shutdown of the beef industry.[2][3] Still, the Texas detection highlights how quickly decades of hard-won progress can be put at risk when global travel, cross-border trade, and illegal movements are not tightly managed.[1][3] As sterile fly releases ramp up and surveillance continues, ranchers are being reminded that the first line of defense is still local eyes on animals—backed by a federal system that must remain focused on protecting both producers and the broader food supply.
Sources:
[1] Web – Flesh-eating screwworm returns to U.S. after 60 years, threatening …
[2] Web – What is the New World screwworm, and why does it matter to Texas?
[3] Web – New World screwworm – Texas Farm Bureau
