06/04/2026
New World screwworm has now been confirmed in a calf in South Texas. This does not mean every farm is under immediate threat, but it does mean livestock owners should be vigilant. Check animals daily for wounds, navels, irritated areas, drainage, foul odor, or larvae. Keep wounds clean and protected, control flies, and contact your veterinarian or state animal health officials immediately if you suspect screwworm. Early detection matters.
USDA confirmed New World screwworm in a 3-week-old calf in LaPryor, Zavala County, Texas, about 50 miles from the Mexico border. AP reports this is the first confirmed Texas case since 1966, and Texas established a 12-mile quarantine zone where warm-blooded animals, including pets, cannot be moved out without inspection. Officials also said there were no other U.S. detections at the time of that announcement. https://apnews.com/article/screwworm-flesh-eating-parasite-cattle-texas-2efc5ec69d9651b5c0bab4825eda4976?utm_source=copy&utm_medium=share
Screwworm flies target open wounds, navels, mucous membranes, cuts, dehorning/disbudding sites, ear tags, castration wounds, kidding injuries, flystrike-prone areas, and any wet/soiled tissue. USDA says NWS larvae burrow into living flesh and can infest livestock, pets, wildlife, birds, and rarely people. Suspected animals should be handled through a veterinarian, and suspected animal disease should be reported through veterinary/state animal health channels. https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm
Check goats daily, especially kids, fresh does, navels, vulvas after kidding, ears, tails, feet, scurs/horn areas, and any scratch or abscess-looking spot. Keep wounds clean, covered/treated as your vet recommends, and watch for larvae, foul odor, bloody drainage, swelling, pain, or an animal acting “off.”
The U.S. Department of Agriculture has confirmed that the New World screwworm fly has arrived in south Texas.
