The threat from the flesh-eating maggots, known as the New World Screwworm, has suspended live cattle imports through the southern border.

The New World screwworm is endemic in parts of Latin America and the Caribbean — and its northward spread into Mexico has alarmed U.S. officials. It can kill a full-grown cow in one to two weeks.

U.S. Agriculture Secretary Brooke Rollins on Sunday said she is suspending imports of live cattle, horse and bison through the southern U.S. border over the damaging pest New World screwworm, following up on a threat she issued last month to her Mexican counterpart.