More than a week after New World screwworm reappeared in Texas, officials say the state's response has shifted into full containment mode.
Eight cases have now been confirmed, millions of sterile flies have been released, quarantine zones have been established, and state agencies have mobilized resources across South Texas in an effort to prevent the flesh-eating parasite from spreading further.
The development has raised concerns across Texas' agricultural industry. Just weeks before the first case was confirmed, experts warned lawmakers that a widespread screwworm infestation could cause billions of dollars in economic losses and require decades of work to eradicate.
Here's where things currently stand in the fight against screwworm.
Confirmed cases have risen to eight
As of Friday, eight cases of New World screwworm have been confirmed in Texas.
The fly's larvae feed on the living tissue of warm-blooded animals, including livestock, wildlife and pets — and, in rare cases, humans. Left untreated, infestations can cause severe injuries and death.
The parasite was first detected in a calf in Zavala County last week, marking the first confirmed U.S. case since the pest was eradicated in the 1960s. Since then, state and federal officials have established quarantine zones and have restricted the movement of animals to prevent the parasite from spreading.
Texas has mobilized state resources
Gov. Greg Abbott last week expanded a disaster declaration that authorizes all available state resources to support containment efforts and accelerate the state's screwworm response.
A key part of that response is the release of sterile male screwworm flies. Female screwworm flies mate only once, so breeding with a sterile male prevents reproduction and helps suppress the population.
Abbott's declaration also aims to speed construction of a $750 million sterile fly production facility at Moore Air Base near Edinburg. The facility is expected to produce up to 100 million sterile flies per week when it becomes operational in 2027.
For comparison, officials say roughly 4 million sterile screwworm flies are already being released each week by air in areas near the U.S.-Mexico border.
The response is also expanding beyond areas where cases have been confirmed. On Friday, Travis County officials announced a preemptive disaster declaration in preparation for the possibility of screwworm detections, despite there being no known cases in the county.
The General Land Office is offering state land for the response
On Wednesday, Texas Land Commissioner Dawn Buckingham offered the U.S. Department of Agriculture access to state-managed lands to support the screwworm response. Buckingham said the land could be used for sterile fly release operations, temporary quarantine zones and livestock monitoring efforts.
"By working together and remaining vigilant, we can protect our food supply and preserve the health of our livestock and wildlife populations," Buckingham said in a statement.
The General Land Office manages more than 100 grazing and hunting leases across 25 Texas counties.
Ranchers are taking precautions
While confirmed cases remain concentrated in South Texas, ranchers across the state are keeping a close eye on their animals and preparing for the possibility of additional detections.
Dace Duke, a cattle rancher near Coleman in Central Texas, told KTTZ that he remembers encountering screwworm infestations while working in the livestock industry as a teenager.
"You definitely know when you have it, because its god-awful smells — dead animals smell — because it's rotten flesh," Duke said.
Ranchers in states along the U.S.-Mexico border are also increasing monitoring efforts. Tom Paterson, president of the New Mexico Cattle Growers' Association, said producers are watching for wounds, unusual behavior, loss of appetite, head shaking, unusual odors and the presence of larvae in wounds.
Because screwworm flies lay their eggs in open wounds, some ranchers are postponing livestock procedures that could create opportunities for infestation.
"If possible, and sometimes it's not possible, we're going to be postponing elective procedures that create open wounds until we know more about the extent of the situation," Paterson said during an appearance on NPR's 1A.
Copyright 2026 KERA News