USDA Mobilizes Against New World Screwworm Outbreak in Texas and New Mexico

In early June 2026, the U.S. Department of Agriculture confirmed the first U.S. cases in 60 years of the New World screwworm, a flesh‑eating parasite, in a calf in Zavala County, Texas, a dog in Lea County, New Mexico, and additional livestock across Texas. The agency has established 20‑km quarantine zones around each detection, deployed an Incident Command Team with the Texas Animal Health Commission, and accelerated the release of sterile screwworm flies—both aerially (4 million per week) and via ground chambers.

USDA is fast‑tracking emergency treatments, building a stockpile in Texas, and has allocated $100 million earlier than planned for new technologies. The Food and Drug Administration granted emergency use authorization for nitenpyram (Capstar) to treat infected dogs and cats, marking the first generic animal drug approved for screwworm. Over 100 USDA staff are now working full‑time on the response, despite a 25 % reduction in animal‑health experts.

Officials warn the pest could raise beef and dairy prices and threaten rural economies, but the food supply remains safe because meat inspection protocols would block contaminated products. The outbreak has prompted tighter interstate animal‑movement rules, new certification requirements for pets traveling across state lines, and renewed calls for coordinated action with Mexican and Central‑American authorities to curb illegal cattle trafficking that may have accelerated the parasite’s return.