Texas livestock report new world screwworm outbreak

U.S. officials confirmed the first case of the New World screwworm in a three‑week‑old calf in Zavala County, Texas, on June 3, marking the parasite’s return to the United States since its eradication in the 1960s. Since early June the USDA has recorded a total of 33 screwworm infections in animals across Texas and New Mexico, affecting cattle, goats and a pet dog.

The USDA emphasized that the screwworm is an animal health issue, not a food‑borne pathogen, and that meat, milk and produce are not contaminated by the parasite. Livestock destined for human consumption must pass USDA inspection before and after slaughter; any animal showing signs of infestation is isolated and labeled a “US Suspect” for further veterinary examination. Infected animals are quarantined until wounds heal, and standard meat‑processing procedures destroy the larvae.

Health officials noted that the screwworm spreads only when adult flies lay eggs in open wounds and does not transmit through meat, poultry or dairy products. Ongoing monitoring and treatment protocols are in place to prevent further spread.