US Recloses Southern Border to Livestock Over Parasite Spread

The United States has reclosed its southern border to livestock imports due to the northward spread of the New World screwworm fly in Mexico, a parasite whose larvae consume live flesh and pose a severe threat to animals like cattle, horses, and bison. U.S. officials fear that if the parasite reaches Texas, it could cause significant economic damage similar to outbreaks experienced decades ago, despite prior eradication efforts in the 1970s using sterile male flies. The parasite has been found approximately 185 miles northeast of Mexico City, about 160 miles further north than previous reports, prompting renewed border restrictions after a brief reopening of some ports. U.S. Department of Agriculture Secretary Brooke Rollins stressed the importance of vigilance and aggressive monitoring in both countries to prevent the fly's spread, while the U.S. is investing nearly $30 million to strengthen sterile fly release programs. Mexican President Claudia Sheinbaum criticized the U.S. response as exaggerated, noting a 19% reduction in infected animals since late June and asserting that Mexico is following all necessary protocols. Meanwhile, some U.S. lawmakers have urged expedited approval of anti-parasite treatments to better combat the outbreak.