The Confirmed Facts

The U.S. Department of Agriculture confirmed a New World screwworm infestation in a three-week-old calf in La Pryor, Zavala County, Texas, according to the Texas Tribune and KGNS. USDA Secretary Brooke Rollins announced the confirmation at a press conference Wednesday.

The sample was tested at USDA's National Veterinary Services Laboratories in Ames, Iowa. Larvae were found in the calf's umbilical cord wound. No additional cases have been reported as of the confirmation.

The USDA has placed a 12-mile quarantine perimeter around the affected ranch and has already deployed expert teams to release sterile flies — the same method used to eradicate the parasite from the U.S. the first time around, per KGNS.

The Significance

The New World screwworm (Cochliomyia hominivorax) is a destructive pest. Female flies lay hundreds of eggs in the open wounds of warm-blooded animals. The larvae then eat living flesh, burrowing deeper as they feed. Left untreated, infestations kill.

The USDA estimates keeping screwworms out of the U.S. has saved the domestic livestock industry $900 million per year, according to Ars Technica. Texas alone runs a $15 billion cattle industry, per the Texas Tribune.

The parasite was eradicated from the United States in the 1960s through a sustained sterile fly release campaign. It's been creeping back north through Central America for years. A confirmed case in the Mexican state of Coahuila — just 25 miles from the Texas border — was reported May 28, according to Ars Technica. Another case in a calf was found 39 miles from the border, also in Coahuila, around the same time.

The McLaughlin Mess

Texas state Rep. Don McLaughlin (R) claimed on social media Monday that a screwworm case had been found just one mile from the Texas border. Secretary Rollins publicly shot that down Tuesday, calling the claim false and warning that it was causing unnecessary panic.

"When that false information gets out, it causes significant panic," Rollins said, according to the Texas Tribune. "And rightly so, especially if it's coming from elected officials and the media."

One day later, McLaughlin was partially vindicated — and partially not. The confirmed case in La Pryor was NOT one mile from the border. It's in Zavala County, which sits roughly 80 miles north of the Rio Grande. McLaughlin had flagged the right ranch, wrong distance. He told Reuters he suspected the fly was present after seeing photos and video of larvae in two calves. USDA confirmatory testing proved him right on the infection, wrong on the geography.

McLaughlin was raising a real alarm. But specifics matter when you're talking about a livestock emergency. Inaccurate details from officials cause real economic damage — ranchers make decisions based on what they hear from their elected representatives.

What the Government Is Doing

The USDA had been preparing for this scenario for months. Houston Public Media reported that Texas officials had already launched a response effort that includes a planned $750 million sterile fly production facility in South Texas. KGNS confirmed sterile flies are already being released around the quarantine zone.

Sterile fly release works by flooding a population with flies that can't reproduce. Females mate once. If that mate is sterile, no larvae. Over time the population collapses. It worked before. The question now is whether the response is fast enough, with the fly already confirmed north of the border.

Rollins said residents near affected areas should check pets for infected wounds and larvae. She also clarified that screwworms do NOT infest food — meat, fruits, and vegetables are NOT affected, per the Texas Tribune. No food supply chain disruption is expected.

What Media Is Getting Wrong

Most coverage is treating this like a crisis that emerged overnight. It didn't. The screwworm has been advancing northward through Central America and Mexico for years. Federal and state agencies have been watching it close in on Texas for months. The $750 million sterile fly facility was announced back in August 2025, per the Texas Tribune. This wasn't a surprise.

Some outlets leaned hard on the "flesh-eating" framing for maximum alarm. The parasite IS dangerous and the threat IS real — but the USDA's containment protocol is tested and proven. Sterile fly release eradicated this exact parasite from the continental U.S. once before. The response infrastructure exists.

One question deserves scrutiny: why the sterile fly facility isn't operational yet. A $750 million facility announced nearly a year ago is apparently not yet producing flies at scale — otherwise the border buffer zone would be thicker.

What Comes Next

For Texas ranchers and pet owners in South Texas: check your animals now. Look for unusual maggots, rapidly worsening sores, and larvae in wounds. Contact a veterinarian or the Texas Animal Health Commission immediately if something looks wrong.

For the broader livestock industry: the 12-mile quarantine and sterile fly deployment are the right moves. Whether they're sufficient depends entirely on how fast this spreads before that response gets traction.

The USDA eradicated this parasite once. The tools are the same. The clock, however, is running.