New World screwworm livestock cases now span multiple Texas counties and have crossed into New Mexico, marking the most serious animal pest crisis America has faced in six decades.
Background on New World Screwworm Livestock Threat
Furthermore, this outbreak did not arrive without warning. Since 2023, an NWS outbreak moved northward through Central America and Mexico, targeting livestock, pets, and wildlife along the way. Notably, USDA eradicated the pest from the United States back in 1966 using the sterile insect technique. However, the parasite re-emerged in Mexico in November 2024, triggering over a year of federal preparedness efforts. In addition, cases rapidly expanded through Costa Rica, Nicaragua, Honduras, Guatemala, Belize, and El Salvador before reaching the U.S. border. Consequently, federal agencies had already begun aerial releases of sterile flies along the Texas border before the first domestic case appeared.
Key Details of the New World Screwworm Livestock Outbreak
Meanwhile, the crisis hit U.S. soil hard and fast. On June 3, 2026, USDA’s Animal and Plant Health Inspection Service confirmed NWS in a 3-week-old calf in Zavala County, Texas. Importantly, this marked the first confirmed U.S. livestock case in the current outbreak — the first since the pest’s eradication 60 years ago. Moreover, USDA’s National Veterinary Services Laboratories in Ames, Iowa, confirmed the case from a sample taken in La Pryor, Texas. As a result, cases grew quickly: by June 9, six total domestic animal cases existed, including four cattle, one goat, and one dog. Furthermore, a pet dog case in Lea County, New Mexico emerged on June 8, 2026, signaling the pest’s potential spread beyond Texas. Today, 14 Texas counties sit under active quarantine orders from the Texas Animal Health Commission.
Industry Impact of New World Screwworm Livestock Cases
Therefore, the economic stakes could not be higher. The New World screwworm could cost the economy billions and drive beef prices even higher for American consumers already facing record costs at the grocery store. Furthermore, NWS larvae burrow into the living flesh of warm-blooded animals, causing severe tissue damage and economic losses to producers. Consequently, the Texas Animal Health Commission placed quarantines across 14 counties, including Coke, Crockett, Edwards, Gillespie, Kerr, Kimble, La Salle, Schleicher, Sutton, Tom Green, Uvalde, Val Verde, Webb, and Zavala. Moreover, all warm-blooded animals inside infested zones require official inspection and a movement certificate before producers can transport them. However, USDA stressed that the U.S. food supply remains safe, as screwworms do not infest meat, fruits, or vegetables.
What Comes Next for New World Screwworm Livestock Response
As a result, USDA launched an aggressive multi-front eradication effort. Secretary Brooke Rollins activated the NWS Response Playbook, establishing quarantines, accelerating sterile-fly releases, expanding border trapping, and intensifying livestock surveillance. Additionally, USDA invested in ramping sterile fly production toward approximately 500 million flies per week — matching the volume used during the original eradication campaign. Furthermore, USDA broke ground in April 2026 on a larger production facility at Moore Air Base near Edinburg, Texas, expected to produce roughly 300 million sterile flies per week once it opens in 2027. In addition, the FDA issued an Emergency Use Authorization for generic Nitenpyram Tablets — the first generic animal drug authorized to treat NWS myiasis in dogs and cats. Meanwhile, President Trump appointed John Bellinger as Senior Advisor for New World Screwworm Preparedness to further coordinate the federal response.
Conclusion
Consequently, the return of New World screwworm livestock infestation stands as the defining agricultural emergency of 2026. Furthermore, producers across Texas and the Southwest must check animals daily for wounds, larvae, and signs of discomfort. Moreover, anyone suspecting an infestation must report it to the Texas Animal Health Commission within 24 hours. Importantly, USDA Secretary Rollins stated that if all stakeholders follow treatment protocols and movement restrictions, there is no reason the pest must establish itself permanently in the country. Therefore, every rancher, veterinarian, and wildlife manager plays a direct role in whether America defeats this parasite again — or faces decades of devastating livestock losses.
Related: New World Screwworm Returns to US Soil After 60 Years
Originally reported by USDA APHIS. Analysis by the GardenScoop Editorial Team.
