A flesh-eating parasitic fly that poses a major threat to livestock has returned to the United States after 60 years. This week, the US Department of Agriculture confirmed the presence of New World screwworm in a calf in southern Texas. Eliminated in the US in 1966 and as far south as Panama by 2006, its recent reemergence in Mexico made it likely that the screwworm would eventually enter the country again, with modeling showing that it could arrive as soon as summer 2025. It took slightly longer, but the screwworm has arrived. And to head off an outbreak, officials are deploying a