Flesh-Eating Fly Breaches Texas

A flesh‑eating parasite just crossed our southern border into Texas cattle, and ranchers are asking if federal officials are moving fast enough to stop it cold.

Story Snapshot

A deadly flesh‑eating screwworm has been confirmed in Texas cattle after decades of absence.
Federal officials are leaning heavily on sterile-fly releases while Texas leaders push to use every tool available.
Experts say the food supply and human health are safe for now, but livestock losses could be severe if the pest spreads.
Trump‑era agriculture leaders face a real-time test of border security, biosecurity, and support for rural producers.

Flesh‑Eating Screwworm Returns to Texas After Decades

The United States Department of Agriculture (USDA) confirmed the New World screwworm, a flesh‑eating fly, in a three‑week‑old calf in Zavala County, Texas, on June 3, 2026.^[1] Inspectors found larvae in the calf’s umbilical area, marking the first U.S. animal case in the current outbreak tied to massive screwworm problems in Mexico and Central America.^[1]^[5] Federal officials say they acted at once to contain the pest and follow their New World screwworm response playbook.^[1] That playbook centers on surveillance, quarantines, and release of sterile flies over the border region.^[1]^[5]

The New World screwworm is not just another nuisance fly. Texas A&M AgriLife experts explain that the insect lays eggs in the living tissue of fresh wounds in warm‑blooded animals, including cattle, wildlife, pets, and sometimes people.^[2]^[4] The maggots then eat living flesh, causing deep, foul‑smelling wounds that can lead to death if not treated.^[2]^[4] This parasite was wiped out in the United States in the 1960s but has now reemerged across Central America and Mexico, where more than 171,700 animal cases and nearly 2,000 human cases have been reported.^[5]

What Federal and State Officials Are Doing Right Now

USDA says it has formed a unified Incident Command Team with the Texas Animal Health Commission to run the response in South Texas.^[1] Officials created a 20‑kilometer “infested zone” around the ranch where the calf was found and put movement controls, quarantine rules, and tight surveillance in place inside that zone.^[1]^[3] Federal teams are also stepping up trapping for screwworm flies along the border and in areas just outside the main sterile‑fly dispersal zone.^[1]^[6] Wildlife surveillance and targeted outreach to local ranchers and pet owners are part of the package.^[1]^[4]^[8]

At the same time, USDA is pushing harder on its long‑running sterile insect program. The agency reports it already releases about four million sterile screwworm flies per week from the air in the region.^[1] After the Texas case, officials began “expediting targeted release” by putting ground release chambers in the local area, on top of those aerial drops.^[1] USDA says it is also dispersing 100 million sterile insects per week in Mexico and along the U.S.–Mexico border, and that it adjusts the size and shape of the release area based on science models and each new case.^[6]^[5] The Centers for Disease Control and Prevention (CDC) backs this strategy, calling sterile fly releases, movement controls, and outreach the core tools to slow and stop the outbreak.^[5]

Are Authorities Moving Fast Enough to Protect Ranchers?

Texas Agriculture Commissioner Sid Miller has taken a more aggressive tone, warning that the very first suspected case “demands use of all available tools” to end the threat.^[3] That language reflects a key concern from many producers: while sterile flies are the proven long‑term answer for regional control, each delay or narrow response on the ground could mean more dead calves and higher costs for family ranches. Texas A&M materials note that U.S. producers have not dealt with screwworm in more than 40 years, so many lack recent hands‑on experience with treatment and prevention.^[2]

AgriLife experts stress that regular, hands‑on inspection of cattle and other livestock is now critical.^[2]^[4] Ranchers are urged to look for foul‑smelling wounds, animals licking or biting at sores, and maggots in navels, ears, or branding and dehorning sites, and to isolate and report any suspicious animals at once.^[2]^[4] Guidance calls for quick cleaning of wounds and, when infestation occurs, the use of topical larvicides such as coumaphos or permethrin under a veterinarian’s direction.^[2] Texas Farm Bureau and the Texas Animal Health Commission echo that daily inspection and rapid reporting are the best way to prevent large‑scale losses.^[8]

Risk to People and the Food Supply

The idea of a flesh‑eating parasite at the border sounds like a horror movie, but federal health officials say there is no immediate threat to the food supply or most Americans.^[1]^[5] USDA states clearly that screwworms do not infest meat, fruits, vegetables, or other food products.^[1] The CDC reports that, as of its latest update, there are no locally acquired human screwworm cases inside the United States, and that the fly itself is not considered established here.^[5] People who were infected have picked up the parasite while traveling in Central America, not in Texas pastures.^[5]

USDA confirms New World screwworm detected in 3-week-old calf in Zavala County, Texas, near US-Mexico border. A 20-km (12.4-mile) infested zone quarantine established & millions of sterile NWS flies will be released in Texas and Mexico in coming days. https://t.co/UWxqUc8CWV

— Reva Katz (@Reva4542) June 12, 2026

Still, the CDC warns that screwworm infestations in people can cause extreme pain, foul‑smelling wounds, and even death if treatment is delayed.^[5] The agency urges anyone who sees or feels maggots in a wound to seek medical care right away and not try to handle the problem alone.^[5] For now, health officials say that keeping wounds clean and covered, using insect repellent in areas where the fly is present, and reporting suspected cases quickly are the best ways to protect both people and animals.^[2]^[4]^[5]