
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.
(Image credit: USDA)

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.
(Image credit: USDA)