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USDA completes NWS sterile fly dispersal facility in Texas

The USDA has completed its U.S.-based sterile fly dispersal facility in Edinburg,Texas, part of the federal government’s efforts to prevent the spread of the New World Screwworm (NWS) into the U.S. This facility expands USDA’s ability to disperse sterile flies along the border and into the United States, if necessary. Agriculture Secretary Brooke Rollins made the announcement Feb. 9.

There have been no reported cases of NWS in the U.S. On Dec. 27, 2025, Mexico reported an NWS case in a six-day-old calf approximately 197 miles from the U.S.-Mexico border.

Action USDA is taking to fight NWS

Rollins said the department is conducting trapping and surveillance efforts along the border and working to stop the pest’s spread in Mexico.

In June 2025, the USDA announced a sweeping five-pronged plan to enhance USDA’s ability to detect, control, and eliminate NWS. As part of that announcement, she also shared plans to build this sterile NWS fly dispersal facility in South Texas. The completion of the facility further expands the network of dispersal facilities through Central America and Mexico and solidifies the increased preparedness offered by having a U.S.-based facility.

On Jan. 30, USDA announced a shift in its 100-million-per-week sterile fly dispersal efforts to reinforce coverage along the U.S.-Mexico border. The sterile flies for this effort will initially be dispersed from the facility in Tampico, Mexico, about 330 miles south of South Padre Island, Texas, on the gulf coast. The USDA indicated it is prepared to quickly and strategically shift operations to the new Texas facility should there be a change in the location or new concentration of NWS cases in northern Mexico.

Sterile insect technique, when paired with surveillance, animal movement restrictions, and education and outreach, is a proven and effective tool for controlling and eradicating NWS. Female NWS flies only mate once in their lives, so if they mate with a sterile male, they lay unfertilized eggs that don’t hatch. Releasing sterile flies just outside of affected areas helps ensure flies traveling to new areas will only encounter sterile mates and will not be able to reproduce.

Sterile insects are dispersed through aerial dispersal or ground release. Aerial operations are preferred because they allow for dispersal at a steady rate through a large area and also because sterile insects may be dispersed in areas that are unreachable from the ground. Ground release is used when there is a need to quickly deploy sterile insects outside of the dispersal facility range. Mass production and targeted dispersal of sterile flies remain critical components of an effective response.

USDA currently produces sterile flies for dispersal at the COPEG facility in Panama. USDA is also investing $21 million to support Mexico’s renovation of an existing fruit fly facility in Metapa, near Mexico’s border with Guatemala – which will double NWS production capacity once complete. With ongoing support from technical experts in USDA’s Animal and Plant Health Inspection Service (APHIS), Mexico anticipates this sterile fly production to begin as soon as summer 2026.

The USDA is also building a sterile fly production facility at Moore Air Base, with a targeted maximum capacity of 300 million sterile flies per week. USDA expects to break ground on that facility later this spring. With existing and planned production facilities fully operational, USDA will have up to 500 million sterile files per week in its arsenal to fight this pest all the way back to the Darién Gap on the Panama/Colombia border. The international network of facilities will produce 100 million sterile flies per week at COPEG in Panama, 100 million at Metapa in Mexico, and 300 million at Moore Air Base.

Be on lookout for NWS in your livestock & pets

There have been no detections of NWS inside the U.S. and the northernmost active case of NWS is still about 200 miles away from the border. The USDA is asking Americans to continue to remain vigilant by checking their livestock and pets for signs of NWS. Look for draining or enlarging wounds and signs of discomfort. Also look for NWS larvae (maggots) and eggs in or around body openings, such as the nose, ears, and genitalia or the navel of newborn animals. If you suspect your animal is infested with NWS, immediately report it to your state animal health official or USDA area veterinarian in charge.

NWS maggots can infest livestock and other warm-blooded animals, including people. They most often enter an animal through an open wound and feed on the animal’s living flesh. While not common in people, if you notice a suspicious lesion on your body or suspect you may have contracted NWS, seek immediate medical attention.

Learn more about NWS and USDA’s efforts, visit www.Screwworm.gov.

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