New World screwworm parasite reappears in Texas, US, prompting large‑scale eradication effort

U.S. Department of Agriculture officials confirmed the first case of the New World screwworm parasite in Texas since 1966 when a three‑week‑old calf on a La Pryor farm tested positive. The parasite’s larvae feed on living tissue and can affect cattle, sheep, wildlife, pets and, in rare cases, humans.

Texas veterinary officials imposed a 20‑kilometer quarantine around the farm, set up road checkpoints and barred the movement of livestock and other warm‑blooded animals until cleared. The USDA also announced a renewed sterile‑male fly program – releasing irradiated male flies that cannot reproduce – to suppress the screwworm population, a method that previously eradicated the pest in the 1960‑70s.

Authorities stress no additional infections have been found and the parasite does not threaten meat safety, but experts warn that undetected spread among wild animals could jeopardise the U.S. beef supply, which is already strained by drought and rising feed costs. The outbreak could cost the livestock sector billions of dollars if not contained.