Screwworm Reappears in U.S.: What Happened and How Officials Respond

By June 8, 2026, officials have confirmed five animal cases of New World screwworm in the United States. The first confirmed animal case was announced on June 3, 2026, when the U.S. Department of Agriculture identified larvae in a young calf in Zavala County, Texas. Two more infections were later found in Texas and one infected dog was reclassified as living in Lea County, New Mexico. No locally acquired human infestations have been reported.

The federal response has moved quickly. USDA and Texas authorities have formed a unified Incident Command Team and established a 20-kilometer infested zone with quarantines and movement controls to limit spread. The agency is releasing sterile New World screwworm flies, including about four million sterile flies per week by aerial dispersal, and has added ground release chambers nearby. Surveillance has been increased and targeted outreach is underway; therefore, veterinarians and livestock owners are urged to check animals for draining wounds and maggots. CDC guidance notes that open wounds should be kept clean and covered, and insect repellent can lower risk. However, the immediate public risk remains low while authorities work to contain the outbreak.