The parasite — the larva of the new world screwworm fly — can devastate cattle herds and is rife in parts of Central America.

A rare case of travel-related New World screwworm was identified in Maryland in a patient who traveled from El Salvador, a spokesman from the US Department of Health and Human Services said.

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