A parasitic threat that the United States had not faced for decades has resurfaced, raising alarm among cattle farmers. The Agriculture Department confirmed that a calf in South Texas has been infected with the New World screwworm, a parasitic fly capable of killing livestock if the infestation is not treated in time. It is the first time the pest has been detected in the country in many years.
Officials sought to reassure the public that the discovery does not represent a food safety problem. The screwworm is not a disease but an insect that feeds on living tissue, and animals treated early enough recover and remain safe to enter the food supply. Even so, the parasite is considered highly destructive because the larvae hook themselves into live flesh and spread aggressively.
The detection comes only days after Agriculture Secretary Rollins dismissed a warning from a local lawmaker who had flagged that screwworm had been found in Mexico, just a mile from the US border. That earlier alert now appears to have foreshadowed the case confirmed on American soil.
The New World screwworm was eradicated from the United States back in the 1960s, making its return a significant setback. A human case was confirmed last year in an international traveler, who recovered. Health authorities stress that the threat to people, especially in the United States, remains very low, with the highest risk falling on those who work closely with livestock.
The greatest concern centers on the beef industry, which is already under strain. Beef prices have climbed about 13 percent over the past year, driven in part by a shortage of cattle. The national herd has fallen to a 75-year low, a decline blamed on extreme weather, high feed costs and consolidation across the industry.
Because cattle are large animals that reproduce slowly, experts warn that any damage caused by the screwworm would take many years to repair. An outbreak among livestock could therefore worsen an already difficult situation for producers and push pressure onto beef supplies and prices.
In response to the detection, the government is ramping up efforts to release sterile flies, a method historically used to suppress screwworm populations, and will quarantine the area in Texas where the infected calf was found. The measures aim to contain the parasite before it can establish itself more widely across the country.