Mexico resumes limited cattle exports to US after screwworm pause, relieving ranchers

Mexico has resumed limited exports of live cattle to the United States after a nearly two-year pause due to a screwworm outbreak, providing a much-needed boost to the country's ranching industry. The trade channel reopening took place in the desert mountains near the U.S.-Mexico border, with cattle crossing from Agua Prieta, Sonora, to Douglas, Arizona.

Authorities conducted thorough inspections, using dogs to ensure the animals were not infected with the flesh-eating screwworm. The screwworm, caused by the Cochliomyia hominivorax fly, infests open wounds and can be fatal to animals, including humans. The pest emerged in Mexico in November 2024 and is now present in 30 of the country's 32 states, including Sonora, Mexico's largest cattle exporter.

The United States first reported screwworm cases in Texas and New Mexico in June. President Claudia Sheinbaum welcomed the reopening, and her administration implemented measures to prevent further outbreaks, such as enhancing cattle tracing systems and dispersing sterile flies in border states like Sonora and Chihuahua, which together account for most cattle exports to the United States.

As of Monday, Mexico had 1,937 active screwworm cases. To comply with the new protocol, U.S. authorities required Mexican cattle to be fitted with radio-frequency identification tags, and scanners were installed to read the tags.