The USDA announced the completion of a U.S.based sterile fly dispersal facility in Edinburg, Texas to expand the dispersal along the border of the United States to help eliminate the New World Screwworm (NWS).
Ag Secretary Brooke Rollin said, “This sterile fly dispersal facility was a high priority project, and our team delivered it in record time. This new facility is a monumental achievement for our domestic preparedness efforts, but we are also diligently working to stop the spread of screwworm in Mexico, conduct extensive trapping and surveillance along the border, increase U.S. response capacity, and encourage innovative solutions.”
In June 2025, Rollins announced a sweeping fivepronged plan to enhance USDA’s already robust 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. While the sterile flies for this effort will initially be dispersed from the Tampico, Mexico facility, USDA 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.
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—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.
Even though 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, 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 an animal is suspected of being infested with NWS, it should be reported immediately to state animal health officials or USDA area veterinarian. These maggots can infest livestock and other warm-blooded animals, including people.