On November 22, the United States Department of Agriculture temporarily halted the import of cattle from Mexico after a flesh-eating parasite was detected in animals in southern Mexico. Before the discovery of cattle screwworm (Cochliomyia hominivorax) at an inspection point in the state of Chiapas, the species had previously been eliminated in North America since the end of the 19th century. The US–Mexico border remains closed to cattle and may not reopen until the new year.
The worm is the larva of a metallic blue-green fly that spends the early part of its life cycle devouring the living flesh of mammals. Infestations can be