New World screwworm cases rise to 15 in Texas

The U.S. Department of Agriculture has confirmed 15 cases of the New World screwworm parasite in Texas, including a lamb in Crockett County and two calves in Edwards County. Earlier detections this year were reported in San Angelo and the first domestic case in six decades was found in a calf in Zavala County, Texas.

The larvae of the fly feed on living tissue of warm‑blooded animals, threatening cattle, sheep, goats, wildlife and, in rare instances, humans. Experts warn that a widespread outbreak could cost Texas up to $1.8 billion in livestock losses.

The USDA is employing the sterile insect technique, releasing millions of sterilized male flies to suppress reproduction. Current production supplies about 100 million sterile flies weekly, but officials say 400 million are needed. New sterile‑fly facilities are under construction in Mexico (expected later this summer) and Texas (operational by the end of next year). Cattle producers have called for greater USDA transparency on the program and its timeline.

Officials emphasize early detection, rapid treatment and ongoing monitoring to limit the parasite’s spread across the southern United States.