Livestock parasite returns to U.S. after 60 years

The USDA confirmed a screwworm—a parasitic fly that kills untreated cattle within weeks—in a Texas calf in June 2026, the first U.S. case since 1966. The pest migrated from Mexico and was spotted within 60 miles of the border in May. For Southern Plains ranchers, it means potential herd losses and complications exporting beef to countries that require pest-free status.