Screwworms are on their way to becoming a billion-dollar international problem but can be contained if ranchers are vigilant, watch their herds and other wildlife, and quickly treat any infestations, U.S. Agriculture Secretary Brooke Rollins said.

After a decade of roiling South Carolina and national politics, Rep. Nancy Mace finished a distant fifth in her state's Republican primary for governor.

Two more cases of the New World screwworm have been confirmed hundreds of miles apart in Texas, demonstrating the difficulty of stopping the spread of a pest that could potentially devastate the nation's cattle industry.