First U.S. Screwworm Cases Since 1966 Trigger Quarantines, Senate Hearing, and Interstate Animal Restrictions

The last U.S. screwworm outbreak ended in 1966 after a 1958-1976 sterile-fly program that cost about $100 million (roughly $900 million in today’s dollars) but paid for itself many times over in avoided livestock losses—much like the 1954 eradication of the cattle fever tick. The 2026 flare-up exposes a recurring pattern: once a pest is pushed south of the border, funding and vigilance wither until climate shifts, cross-border trade, or policy vacillation (e.g., the 2025 re-opening of cattle ports) let it slip back. Politicians’ blame-casting—whether at immigration policy or agency budgets—mirrors the partisan bickering seen during the 2015-2016 avian-influenza cull, yet pathogens and parasites care little for talking points. Over a 100-year horizon, the real signal is the growing reliance on bio-insecticidal and genetic techniques versus chemicals, and the increasing role of interstate movement rules—trends that will shape how North America manages transboundary livestock threats long after today’s beef-price headlines fade.