By Bernt Nelson
Farm Bureau
To protect the U.S. from a new threat posed by an old foe, the New World Screwworm (NWS), the U.S.-Mexico border was closed on May 11 to cattle, bison, and horses from Mexico. This pest was eradicated from the U.S. in 1966 and eliminated as far south as Panama by 2000. NWS began re-emerging above the biological barrier in Panama in 2022 and has continued moving north through Central America and Mexico.