Mexico has resumed live cattle exports to the United States, ending a nearly two-year halt imposed by the Trump administration due to a screwworm outbreak. The resumption of trade on Monday brings relief to Mexico's ranching sector, which experienced an economic downturn as a result of the restrictions. The flesh-eating parasite is now present on both sides of the U.S.-Mexico border.
Hundreds of cattle began crossing from Agua Prieta, Sonora, into Douglas, Arizona, after hours of inspections by Mexican and U.S. authorities. Officials used dogs to screen each animal for screwworm, a parasite whose larvae are produced by the Cochliomyia hominivorax fly. The fly invades open wounds or mucous membranes of warm-blooded animals, including humans, causing increasingly deep and painful tissue damage.
The screwworm outbreak began in Mexico in November 2024 and has since spread to 30 of the country's 32 states, including Sonora. In the United States, initial cases were reported in Texas and New Mexico in June 2024.
Mexican President Claudia Sheinbaum's administration has implemented measures to combat the outbreak, including reinforcing cattle tracing systems and continuing the dispersal of sterile flies in border states like Sonora and Chihuahua, which are major cattle exporters to the U.S. Currently, Mexico reports 1,937 active screwworm cases.
To facilitate the resumption of exports, U.S. authorities approved a new protocol. This protocol mandates the use of radio-frequency identification (RFID) tags in the cows' ears and the installation of scanners to detect these tags. Initially, cattle crossings into Arizona are limited to 700 head per day. This number is scheduled to increase to 900 head per day next week and 1,300 head per day the following week.
The previous Trump administration controls, implemented during the screwworm crisis, contributed to a significant decline in U.S. cattle numbers, reaching a 75-year low. This shortage created a deficit of approximately 1.2 million cows, leading to a surge in beef prices.