Two more cases of the New World screwworm have been confirmed in Texas, demonstrating the difficulty of stopping the spread of a pest that potentially could devastate the nation’s cattle industry. The U.S. Department of Agriculture announced Monday the new cases were found in a calf and a dog, hundreds of miles apart. The screwworm is actually a fly, which produces a larva that eats live flesh instead of dead material. Females lay their eggs in open wounds any any warm-blooded animal such as cattle, but wildlife, pets and occasionally even humans can be infested. Before it was irradicated in the 1960s, the fly was an annual wamr-weather scourge of cattle ranchers.