US detects New World screwworm parasite in Texas cattle

The U.S. Department of Agriculture confirmed the first New World screwworm (Cochliomyia hominivorax) case in Texas since 1966, identifying larvae on a three‑week‑old calf in La Pryor, about 30‑50 km from the Mexican border. The parasite, a flesh‑eating fly whose larvae feed on live tissue, can cause severe losses in cattle herds and has been linked to potential $1.8 billion damages to Texas livestock.

USDA and Texas officials have established a 20‑km quarantine zone around the infected farm, prohibited animal movements within a 40‑km radius, and are preparing to release sterile male screwworm flies to curb spread. Funding has been allocated for mass‑rearing facilities in Texas and Panama to produce hundreds of millions of sterile flies weekly. The USDA’s response was criticized by Texas Agriculture Commissioner Sid Miller, who said the agency moved too slowly.

Veterinarians are urging producers to inspect animals for wounds or eggs and to remove any larvae promptly, a labor‑intensive process. The outbreak reappears after decades of eradication, raising concerns about renewed threats to the U.S. cattle industry.