U.S. reopens Mexican cattle imports Aug. 24 after screwworm ban

The United States announced Friday that it will begin reopening its border to Mexican cattle imports on Aug. 24, ending a suspension that lasted more than a year. The measure was imposed after the New World screwworm spread to Mexico, a parasitic larva of the Cochliomyia hominivorax fly that attacks warm-blooded animals, including humans. The reopening will commence at the Douglas, Arizona border crossing, which borders Agua Prieta in Mexico's Sonora state. The U.S. Department of Agriculture said the subsequent reopening of the Santa Teresa and Columbus border crossings in New Mexico will follow without specifying dates.

Imported cattle will be subject to strict conditions. U.S. authorities have established a joint action plan and will conduct inspections of all animals entering the country to prevent screwworm larvae from crossing the border. U.S. Secretary of Agriculture Brooke Rollins stated in the Department of Agriculture's announcement that it is now safe to reopen the crossing through Arizona, providing the rationale for the decision.

The threat, however, remains present on both sides of the border. In Mexico, the screwworm outbreak was detected in November 2024 and has since spread to 29 of the country's 32 states, with official figures reporting 1,792 active cases. In the U.S., the screwworm was detected last month in Texas and southeastern New Mexico, with more than 30 cases reported to date. Mexican President Claudia Sheinbaum, who was notified of the U.S. decision in a letter from Secretary Rollins, said Mexico will accelerate its efforts to resume cattle movement through Sonora and subsequently through the border state of Chihuahua, where five cases of screwworm were recently reported. Sheinbaum characterized the reopening as an example of "dialogue, cooperation, and collaboration with mutual respect between Mexico and the United States."

The livestock sector's losses during the suspension underscore the economic stakes. Mexico's livestock industry estimated that the ban caused multimillion dollar losses, creating strong incentive for both countries to coordinate a safe reopening while managing ongoing containment efforts.

The reopening marks a partial resolution to a trade dispute triggered by the screwworm outbreak detected in Mexico in November 2024. The ban, which lasted more than a year, caused multimillion dollar losses to Mexico's livestock sector—a significant economic pressure that likely shaped both countries' motivation to resume trade. However, the decision comes despite ongoing risk: the parasite remains active on both sides of the border, with Mexico reporting 1,792 cases and the U.S. confirming spread to Texas and southeastern New Mexico. The phased reopening—beginning with the Arizona crossing while delaying New Mexico border posts—suggests a cautious approach that balances economic recovery with disease containment. U.S. authorities' confidence in the Arizona crossing, backed by inspection protocols and a joint action plan, reflects reliance on monitoring and compliance rather than elimination of the threat. Mexico's commitment to accelerate containment efforts, particularly in Sonora and Chihuahua, indicates both countries view the reopening as contingent on continued outbreak suppression.