A deadly screwworm outbreak near the U.S. border threatens livestock, prompting urgent U.S. containment efforts.

A New World Screwworm outbreak, eradicated from the U.S. since the 1960s, has reached Sabinas Hidalgo, Nuevo León, Mexico—less than 70 miles from the U.S. border—posing a growing threat to livestock and food security. The parasitic fly lays eggs in wounds, leading to fatal tissue damage in warm-blooded animals. The USDA is responding with a five-part strategy, including $750 million for a sterile fly facility in Texas, intensified surveillance across border states, and import restrictions on cattle, bison, and horses from Mexico. Over 13,000 samples tested in the U.S. have shown no detections, but authorities remain vigilant, preparing for potential spread and working with Mexico to contain the outbreak.