USDA unveils Texas screwworm facility, eradication strategy amid reopening of southern ports

The U.S. Department of Agriculture is ramping up detection and containment efforts to prevent New World screwworm (NWS) from entering the country. The parasitic pest, detected in Mexico, has the potential to cause significant harm to the U.S. livestock industry.

Most recently, Secretary of Agriculture Brooke Rollins outlined a five-pronged eradication plan centered around animal-movement controls, surveillance systems and public outreach, and sterile insect technology and exploration of additional innovative strategies.

Rollins made the announcement June 18 during the ceremony at an $8.5 million sterile fly dispersal facility, located at Moore Air Base in Mission, Texas, near the border with Mexico, which will be completed by the end of the year.

These flies are crucial for the Sterile Insect Technique (SIT), a method of controlling and potentially eradicating screwworm infestations in livestock and other animals. The facilities are designed to house large numbers of flies, from larvae to pupae to adults, and include areas for insect rearing, irradiation (to sterilize the males), and other necessary functions like waste treatment and security.

The USDA is also set to begin risk-based port reopenings for cattle, bison, and equids from Mexico. On June 30, the USDA announced a phased reopening of the southern ports of entry, starting with Douglas, Arizona, beginning as early as July 7. Additional port openings will be based on the number of cases and potential northward movement of NWS, Mexico’s continued efforts to curb illegal animal movements, and implementation of further inspection and treatment protocols.

This past May, the USDA suspended imports of live cattle, bison, and equids from Mexico into the United States due to the continued and rapid northward spread of NWS, the USDA explained. During the weeks of June 2 and June 16, teams of USDA experts conducted onsite assessments of Mexico’s NWS response efforts to fully reassess the risk of NWS incursions to the United States posed by importation of Mexican cattle across the southern border.

USDA’s eradication plan

The plan, which builds on NWS protocols established by the USDA’s Animal and Plant Health Inspection Service (APHIS), is as follows:

• Cross-border eradication collaboration: The USDA is investing $21 million in sterile fly production capacity through renovations at a Metapa, Mexico, facility, projected to yield 60-100 million sterile flies per week once the work is completed in about 18 months. This capacity will be in addition to the 100 million sterile flies already produced at the Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG) facility for dispersal in Mexico. USDA health officials recently completed on-the-ground audits of Mexico’s animal health systems and will continue to provide traps, lures, and technical support.
• Enhanced border protection: Strategic trapping efforts and data-sharing agreements are being strengthened along the U.S.-Mexico border. Increased outreach efforts aim to raise situational awareness in livestock corridors. APHIS employees, working alongside U.S. Customs and Border Protection, will monitor, intercept, and treat any unauthorized livestock crossings. In addition, the agency will continue enhanced inspection of live animals at ports of entry from Mexico if or when ports are reopened.
• Preparedness and rapid response: The USDA is coordinating with state animal health officials to update emergency protocols and conducting simulation training exercises with state and federal emergency responders. The USDA has also pledged to ensure there will be enough treatments available, if need. “While we do not anticipate shortages of therapeutics, (the USDA will) prepare to stockpile to backstop any needs while commercial developments accelerate,” according to the plan.
• Sterile fly dispersal and production: In addition to the Moore Air Base dispersal facility, the USDA is evaluating plans for adding another domestic sterile fly production facility capable of generating up to 300 million sterile flies weekly. Another possibility is creating modular sterile fly production facilities and other technologies that may provide quicker construction and surge capacity in the future.
• Innovation and research investment: The USDA is expanding research into sterile insect technology, including looking into e-beam and other radiation technology to produce sterile flies or developing additional or modified genetic strains of NWS, along with next-generation trapping tools. Partnerships with universities in Texas, Arizona, and New Mexico are also being formed to support training and outreach initiatives.

Public input will be solicited through four listening sessions focused on sterile fly production technology see sidebar). The first, held June 27, focused on technological advancements. Rollins emphasized that stakeholder engagement will play a critical role in shaping the USDA’s next phase of action.

Collaborative efforts

The department’s actions follow recent NWS detections in Mexico’s Oaxaca and Veracruz states, approximately 700 miles south of the U.S. border. In response, USDA officials suspended live imports of cattle, horses, and bison through all southern border ports of entry on May 11.

“NWS poses a direct threat to our food supply, economy, and livestock health,” Rollins said according to a USDA press release. “The United States has eradicated this pest before, and with the full deployment of our technical resources and international partnerships, we are prepared to do so again.”

Although the United States has remained free of NSW for decades, the reemergence of screwworms in Mexico has prompted urgent action. The screwworm, Cochliomyia hominivorax, infests wounds in warm-blooded animals, causing tissue destruction and, in severe cases, death. Human cases, while rare, have been documented.

Buck Wehrbein, president of the National Cattlemen’s Beef Association, said in a statement that the only way to protect U.S. cattle for New World screwworm “is by having a sufficient supply of sterile flies to push this pest away from the border.”

“To accomplish that, we need a sterile fly production facility of our own in the United States. Moore Air Base was previously part of our nation’s screwworm eradication effort in the 1960s and now this base will be the cornerstone of our renewed fight against this parasite,” Wehrbein said.

Texas Gov. Greg Abbott praised the announcement, calling the facility a “critical step” in protecting the agricultural backbone of the state. “Texas is on the front lines of the threat posed by the New World Screwworm,” Abbott said in the press release. “We are grateful for the Trump administration’s continued support as we work together to eliminate this pest.”

Abbott also directed the Texas Parks and Wildlife Department and the Texas Animal Health Commission to establish a joint Texas New World Screwworm Response Team to help prevent the pest from entering the state.

“The mission for the Response Team is clear: to lead Texas’ prevention and response efforts and ensure that Texas remains informed, prepared, and aligned to prevent the re-emergence of this destructive parasite,” Abbott’s letter states.

In Arizona, universities and state agencies are collaborating on various early detection efforts such as deploying traps, validating surveillance data, and educating personnel how to identify and respond to NWS infestations, according to the Havasu News.

A version of this story appears in the August 2025 print issue of JAVMA