A suspected case of the flesh-eating New World screwworm has emerged in South Texas, sparking concern among ranchers and authorities. The USDA is investigating samples taken from calves in La Pryor, Texas, where larvae resembling the screwworm were found in wounds.
Agriculture Secretary Brooke Rollins cautioned against misinformation, stating that false reports cause significant panic. The larvae, if confirmed, would mark a potential breach in the biological barrier that has kept the parasite out of the U.S. since its eradication in the 1960s.
Screwworms were eliminated using the Sterile Insect Technique, which involved releasing sterile male flies to outcompete fertile ones. The method succeeded in Central America, but the barrier along the Darién Gap was breached in 2022, allowing the flies to migrate north. In response, the USDA is ramping up surveillance and constructing a sterile fly facility in South Texas, releasing 100 million sterile insects weekly.