The U.S. has again ceased livestock imports from Mexico related to the presence of the parasitic New World screwworm fly closer to the border.

The U.S. has shut its southern border to livestock imports again after a flesh-eating parasite was found further north in Mexico than previously reported, raising alarm among American agriculture officials.

Imports of livestock from Mexico will resume in phases starting next week after a ban in May at ports of entry because of fear of the spread of New World screwworm, the U.S. Department of Agriculture announced Monday.