TEXAS — The U.S. Department of Agriculture confirmed cases of New World screwworm in more than 30 cows, sheep, and goats in Texas over the past month. The agency has started construction on a sterile fly production facility in South Texas to combat the outbreak.

The World screwworm is a flesh-eating maggot that burrows into the wounds of warm-blooded animals. The United States formally eradicated the pest in the 1960s by releasing sterile male flies into the environment. Sterile male flies mate with normal screwworm flies to reduce the population.

The sterile fly production facility in Texas is set to start producing flies in 2027. Until summer 2026, a U.S. Department of Agriculture facility in Panama was the only one producing sterile flies. The States and Mexico inaugurated a sterile fly production plant in southern Mexico in late June 2026.

"Mexico is a critical partner in all this with us," Dudley Hoskins, an undersecretary at the U.S. Department of Agriculture, said. The agriculture departments of the States and Mexico have been in contact regarding the spread of the World screwworm. Mexico has been dealing with a World screwworm outbreak for more than 18 months.

The Mexican government has provided ranchers with kits to collect samples of possible screwworm maggots for testing and medicine to treat open wounds. Sonora, Mexico, has not had any cases of World screwworm. Victor Lezama is a veterinarian who runs a depot for the state cattle ranchers' union in Sonora, Mexico.

A border closure for Mexican livestock has been in place for nearly a year to protect the States from screwworm. The States cattle herd has reached a 75-year low. Texas had a population of 29,243,342 according to the U.S. Census Bureau 2022 American Community Survey.

Julio Berdegue served as Mexico's agriculture minister until spring 2026. "If you lose the trust - the collaboration of ranchers? You're dead," Berdegue said. Phillip Kaufman is the head of the entomology department at Texas A&M University.

"We don't want very many more of these infestation zones, or it's really going to stress the supplies that we have," Kaufman said. The USDA-APHIS has issued a formal environmental assessment for the Texas sterile fly production facility, which was published on July 15, 2026. The USDA-APHIS has allocated $25 million in fiscal year 2026 for screwworm eradication efforts, including the Texas facility. The Texas sterile fly production facility is expected to produce 50 million sterile flies per week once fully operational, according to USDA-APHIS projections.

The confirmation of World screwworm in Texas livestock marks a significant challenge to the States' eradication status. The pest, which was eliminated in the 1960s, threatens the U.S. cattle herd, which has reached a 75-year low. The outbreak in Mexico has persisted for more than 18 months, prompting cross-border cooperation and the acceleration of sterile fly production capacity.

The new facility in Texas represents a strategic shift in containment efforts, moving production closer to the border. With the Panama facility serving as the sole producer until summer 2026, the addition of plants in Mexico and Texas aims to bolster supplies. The $25 million allocation and the projected production of 50 million sterile flies per week reflect the scale of the response required to protect the livestock industry.