On June 3, 2026, the USDA's Animal and Plant Health Inspection Service (APHIS) confirmed the detection of New World screwworm (NWS) in a three-week-old calf in Zavala County, Texas — the first confirmed domestic animal case in nearly 60 years, since the pest was eradicated from the United States in 1966. The calf, found approximately 50 miles from the Mexican border at a ranch in La Pryor, had larvae identified in its umbilical area. The animal was treated and survived.
By June 8, 2026, USDA had confirmed five additional cases: a second calf in Zavala County, a calf in La Salle County, approximately 80 miles southeast of the original detection, a goat in Gillespie County, about 170 miles north, and an infested dog whose tissue samples were submitted by a veterinary clinic in Andrews County, nearly 400 miles north of Zavala County. That dog case was reclassified: USDA APHIS announced the dog actually resided in Lea County, New Mexico, making it the state's first confirmed NWS case.
