While rare in humans, the parasite is a major concern for livestock, with infestations capable of devastating cattle populations.

The U.S. has confirmed a rare human case of New World screwworm, a flesh-eating parasite that typically infects livestock but can be deadly to people too. A Maryland resident suffered an infestation of the screwworm after traveling to El Salvador,

The patient had traveled to Central America, where an outbreak of myiasis, an infection by screwworm larvae, has been ravaging livestock.