METAPA, Mexico — Mexican and U.S. officials inaugurated a sterile fly production facility in southern Chiapas on June 27 as part of efforts to combat the ongoing New World screwworm outbreak that has affected livestock and disrupted cattle trade across the U.S.-Mexico border. The new plant, located in Metapa near the Guatemala border, represents a binational initiative costing over $50 million and is expected to produce up to 100 million sterile flies weekly to suppress the pest population.

The screwworm, a parasitic larva that burrows into the flesh of warm-blooded animals and can be fatal if untreated, has posed a significant threat to livestock health since Mexico first reported cases in November 2024. The infestation spread rapidly through Mexico and was confirmed in early June in Texas, marking the first cases in the United States in decades. This development has raised concerns about potential impacts on the U.S. cattle industry, leading to increased vigilance and responses from both countries.

Mexican President Claudia Sheinbaum and U.S. Agriculture Secretary Brooke Rollins attended the facility's opening, emphasizing the importance of collaboration in addressing transnational animal health challenges. “Animal diseases, pests and the challenges of food safety aren’t limited by borders,” Sheinbaum said, underscoring the necessity of joint efforts in combating the outbreak. Rollins expressed confidence in the project’s potential, noting, “Our countries have beaten this before, 40, 50 years ago. We will beat the New World screwworm again sooner than anyone would have thought because of the extraordinary work that is going to happen at this facility.”

The outbreak has already affected more than 30,000 animals in Mexico and prompted significant trade restrictions. Since May 2025, the United States has largely closed its border to live cattle imports from Mexico, a move that disrupted a supply chain that had previously supplied over one million animals annually to U.S. feedlots. This restriction has contributed to tightening cattle supplies, particularly in Texas.

Although the new plant is expected to notably increase the availability of sterile flies for release—doubling production compared to what is currently produced by the Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG)—experts caution that even this expanded capacity may not be sufficient for complete eradication. The U.S. is also developing its own sterile fly production facility in Texas to bolster containment efforts.

Despite early warnings from COPEG beginning in 2023 about the northward movement of the screwworm, containment efforts were challenged, and coordinated responses only materialized more than a year after the initial outbreak. The inauguration of the Metapa plant marks a significant step toward addressing the outbreak through increased sterile fly releases aimed at suppressing wild populations and ultimately controlling the spread of this damaging livestock parasite.