Importation of Cattle Paused Due to Screwworm Outbreak

Cattle, horses, and bison imports from Mexico have been temporarily paused to prevent the spread of the New World Screwworm (NWS). The suspension of imports was announced on May 11, 2025, by U.S. Secretary of Agriculture Brooke Rollins and will be reviewed monthly to prevent the parasites from crossing into American territory. 

The New World Screwworm is a flesh-eating parasitic fly that is a serious threat to livestock and wildlife. It was eradicated over 60 years ago in 1966, thanks to an effort made by the U.S. government to introduce sterile variants into the population. The program was long and costly, but proved to be effective. 

The USDA confirmed recent detections of the New World Screwworm in remote areas of Oaxaca and Veracruz, two Mexican states located roughly 700 miles south of the U.S.-Mexico border. Even though the U.S. has paused imports, it doesn’t mean the insect isn’t making its way northward. States close to Mexico, like Texas, New Mexico, and Oklahoma, are concerned about the close proximity of the screwworms. 

Rollins characterized the decision as “a national security issue of the utmost importance,” warning that “the last time this devastating pest invaded America, it took 30 years for our cattle industry to recover.”

The USDA has been monitoring the pest’s presence throughout Latin America and the Caribbean, and this hasn’t been the only time the U.S. has suspended trade over the border. In November 2024, the U.S. also paused cattle imports after the insect was spotted near the Guatemalan border. It was lifted in February 2025, but a new restriction was to be placed only months later.