Overview
Longtime South Texas ranchers woke this week to a stark reminder of a pest that once ravaged livestock across the country. Two infestations of New World screwworm have been confirmed in Texas - the first detections in the United States since the 1970s - and the reaction among local livestock owners is split between cautious support for federal containment efforts and mounting distrust born of earlier outbreaks.
Firsthand memories and renewed alarm
Susan Storey, 62, said visceral memories of the last endemic period remain with her decades later. She described seeing maggots burrow in living animals and recalling the smell of carcasses when calves had to be destroyed. Those scenes inform her present-day urgency. "We're fighting for this so our grandchildren can keep what we have," she said as she drove past pastureland and grazing cattle. "I don't want my herd threatened."
Screwworms are parasitic flies whose females deposit eggs in wounds on warm-blooded animals. When the eggs hatch, hundreds of larvae feed on living flesh with mouthparts adapted to burrowing into tissue, and untreated infestations can kill the host. The pest mainly spreads through movement of infested animals. Experts say screwworms do not pose a threat to food safety and rarely affect humans. Agriculture Secretary Brooke Rollins noted that the last time screwworm was endemic in the United States, it took the cattle industry 30 years to recover.
Federal and state response
Federal and state agencies have moved quickly to implement containment measures around the detection sites. Officials established a quarantine zone roughly 12 miles wide centered on the initial detection area and increased trapping and surveillance. Response teams were deployed to the region and authorities continued releasing sterile male flies, part of the eradication technique that originally removed the pest from U.S. livestock decades ago.
"Well before the first U.S. detection of New World Screwworm, since February of 2025, USDA has worked around the clock with our state, local, industry, and ranchers on the ground. The secretary herself made four trips to South Texas, more than anywhere else in the country," a USDA spokesperson said. "The idea that this department has not been transparent is absurd and does not match what ranchers are telling the department and our partners directly."
At the same time, personnel shortages in the animal health arm of the USDA have reduced the number of specialists available to respond to outbreaks. Hundreds of veterinarians, support staff and lab workers left the agency after a period in which departures were pushed, raising concerns among some ranchers about preparedness and institutional capacity to manage animal disease emergencies.
Local reaction: friction and cooperation
Local meetings have reflected the tension. About 100 ranchers filled a small high school cafeteria for a Texas Animal Health Commission briefing, pressing officials with questions and expressing frustration at what they described as a slow federal response. John Paul Schuster, a 55-year-old rancher and county judge, told the room, "As Texans, we're not afraid to take this on," drawing applause and approving nods.
Several ranchers fault the pace of sterile fly production and the number of sterile flies currently available. Historically, eradication depended on releasing vast numbers of sterilized male screwworm flies so that wild females produced infertile eggs. With current production well below what would be needed to suppress a larger outbreak, two new sterile fly production plants are under construction but not yet at capacity. Some local producers are even proposing to raise funds to build a privately financed sterile fly facility at an estimated startup cost of roughly $4 million.
Schuster expressed alarm at the potential local economic consequences if construction and containment do not accelerate. "If it's not controlled in two years and eradicated in five years, my little county will be done," he said, warning that a wider infestation could imperil ranching and hunting activities that underpin the county's economy.
Transparency and practicality concerns
Some ranchers have criticized what they see as insufficient transparency from federal authorities. The USDA's decision not to disclose exact coordinates of sterile fly release sites drew particular ire. "We need to know what's being done because it's our financial investment. It's our livelihood that's on the line," Storey said. "They're not betting their herd - they're betting ours."
Other operators questioned the feasibility of recommended mitigation measures for large, labor-constrained ranches. The USDA has advised daily inspections and preventative treatments, but many producers contend those steps are impractical when herds span thousands of acres, experienced labor is scarce and traditional ranching resources are harder to come by.
"It's not really feasible. There's no more cowboys anymore and there's no good ranch horses," said DJ Rubio, 62, who runs a spread alongside his wife.
Voices urging cooperation
Not all ranchers are critical. Monty Martin, 61, who lives near the positive detection sites in Zavala County, praised federal and state teams working locally. "People need to stop politicizing this, stop finger pointing, it doesn't do anyone any good," he said. "Those people that are on the front lines have been tremendous, and I have the utmost respect and admiration for them."
Major roads leading to the quarantine area are marked with blinking orange signs directing vehicles transporting livestock to pull into checkpoints staffed by state inspectors charged with examining animals for signs of screwworm, although the signs and checkpoint personnel were not present by early evening.
Responsibility for spotting initial infestations remains largely with ranchers. Anthony Gallegos, 43, a Zavala County producer who keeps a relatively small herd and said he has a close relationship with his cattle, described heightened vigilance and said he follows USDA recommendations for preventative medications and inspections. "Come on, girls," he called as a herd trotted toward him, lured by a bucket of feed. "They just pretty much run to me like their dad's here."
Gallegos acknowledged the financial risks if screwworm spread more widely. "If it is widespread and it starts infecting animals, it's going to hurt our bottom line," he said. "Every time I see a buzzard, my heart sinks."
Economic stakes and next steps
Ranchers and officials have been bracing for a domestic U.S. case for more than a year as screwworm advanced northward through Mexico. Experts have warned that a large-scale outbreak could inflict substantial economic damage and be devastating for wildlife. One estimate cited by local voices projects up to $1.8 billion in economic losses to the state if the pest became widespread.
Federal and state teams say they will continue trapping, surveillance, quarantines and sterile fly releases as they attempt to contain the Texas cases and prevent establishment of the pest in the United States. Some ranchers remain skeptical about the sufficiency and speed of those measures and are exploring private solutions to bolster available eradication tools.
For now, the burden of early detection remains with producers who patrol their pastures and look for telltale signs. How quickly sterile fly production scales and whether containment measures hold will determine whether this renewed outbreak becomes a transient emergency or a prolonged economic and ecological threat.