Cattle-Killing Parasite Slips Back In

A flesh-eating livestock parasite once wiped out in America is back in Texas, and Washington is racing the clock to keep it from our herds and our dinner tables.

Story Snapshot

US officials confirm New World screwworm in Texas cattle for the first time in decades, threatening livestock and wildlife.^[1]
Experts warn the parasite can kill an infested animal in days and trigger multi‑billion‑dollar losses if it spreads unchecked.^[18]^[12]
USDA and Texas leaders are rolling out quarantines, checkpoints, and mass releases of sterile flies to stop an outbreak.^[1]^[2]
Health agencies say the risk to people and food is low for now, but ranchers must inspect animals and report suspect cases fast.^[3]^[7]^[8]

A Dangerous Pest Returns to U.S. Soil

The New World screwworm is a parasitic fly whose larvae eat living flesh, not dead tissue, in warm-blooded animals.^[18] Female flies lay eggs in fresh wounds or openings on cattle, horses, wildlife, pets, and sometimes people, and hundreds of larvae can hatch in a single sore.^[18]^[20] These larvae tunnel deeper into the flesh in a corkscrew pattern, causing severe pain, foul-smelling wounds, infection, and often death if the animal is not treated quickly.^[18]^[20] This pest was declared eradicated from the United States in 1966 after a massive federal campaign, making its confirmed return in a Texas calf near the border a serious red flag for producers who already feel stretched by high costs and past policy failures.^[1]^[21]

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service confirmed New World screwworm in a three-week-old calf in Zavala County, Texas, with larvae in the navel area, a common target in newborn livestock.^[1]^[15] That single case has now been followed by additional confirmations in South Texas, with local outlets and federal briefings reporting several active cases and an emergency declaration by Texas officials.^[11]^[9]^[16] USDA’s own invasive species profile still says the parasite is not considered established nationally, but biosecurity experts warn that Texas offers ideal conditions for the fly, and modelers flag the state as high-risk for long-term establishment if response falters.^[5]^[2] For families whose livelihoods depend on cattle, hunting leases, and rural tourism, this is not a distant science story; it is a direct threat to the animals they raise and the income they count on.

How USDA and Texas Are Fighting the Outbreak

USDA and Texas agencies say they moved fast once the Texas case was confirmed, following a formal New World screwworm Response Playbook built from past eradication campaigns.^[1] Officials describe a “One Health” operation that ties together federal veterinarians, the Texas Animal Health Commission, and Texas Parks and Wildlife to trap flies, check animals, and educate landowners in infested zones.^[2]^[7] That response includes animal movement controls, surveillance at checkpoints, and both ground and aerial releases of millions of sterile male screwworm flies that mate with wild females and block them from producing viable offspring.^[2]^[1]^[21] Texas agriculture leaders, however, have publicly blasted earlier federal efforts as “slow” and “inadequate,” reminding ranchers that USDA already tested and proved this sterile fly strategy decades ago and must now deploy it at full strength, not half-speed, when American herds are on the line.^[5]^[6]

Current health guidance stresses two key points: this is a serious livestock problem, but it is not yet a broad human-health crisis. CDC reports more than 185,000 animal cases and at least 1,190 human cases across Central America and Mexico since 2023, yet no locally acquired human infestations from the current outbreak have been documented in the United States.^[3]^[13]^[1] USDA’s unified screwworm page and Texas health officials both say the immediate risk to American people remains low and the U.S. food supply is safe, because meat inspectors reject animals that show signs of active infestation and the larvae do not live in processed meat, fruits, or vegetables.^[7]^[17]^[1] For most readers, that means good news at the grocery store; for ranchers, it means the fight is happening on their pastures and pins, not in city hospitals.

What Ranchers, Pet Owners, and Voters Need to Do Now

Livestock experts agree on one thing: early detection is the difference between a treatable case and a dead herd. Texas A&M AgriLife warns that screwworm infestations can kill infected cattle within about ten days if wounds are ignored, and that unchecked spread in Texas alone could cost $2.1 billion in the cattle industry and $9 billion in hunting and wildlife losses.^[1]^[12]^[18] Ranchers are told to inspect animals regularly, checking navels of newborn calves, branding and castration sites, ears, and any cuts for foul smells, draining sores, or visible maggots.^[20]^[8] Any suspected animal should be isolated, reported immediately to a veterinarian or state animal health official, and treated with wound cleaning, physical removal of larvae, and topical insecticides under veterinary guidance.^[8]^[20] Pet owners in affected counties are being urged to do the same daily checks on dogs, cats, and horses and to keep open wounds clean and covered.^[3]^[8]

A New World Screwworm health alert has been issued near Taylor County.

Cases have been confirmed across several Texas counties and are getting closer to home.

Now is the time to check your animals and stay informed. Share this with anyone who has livestock or outdoor pets. pic.twitter.com/ZQsM0k9ydk

— Abilene Health Dept (@AbileneHealth) June 23, 2026

For conservative voters who care about secure borders, a strong farm economy, and limited but competent government, this outbreak is one more sign of how global problems land hardest on rural America when Washington looks away. Scientists trace today’s cases to a 2023 breach in Central America and steady northward spread through Mexico, including detections just miles from Texas in 2024 and 2025, while federal models warned that Texas was highly suitable for the fly.^[4]^[2]^[18] Now, under a Trump administration that campaigned on defending American producers, regulators are finally reactivating tools—like sterile insect facilities in Texas and stricter livestock import rules—that should have been strengthened years earlier.^[3]^[2]^[21] The path forward is clear: keep up strict surveillance and movement rules, fully fund sterile-fly releases and border controls, and back the ranchers and veterinarians doing the hard work in the field, before a once-eradicated parasite turns into a slow-motion disaster for U.S. agriculture.