The first human screwworm case in the U.S. has been traced to a person in Maryland who traveled from Guatemala.

A human case of a flesh-eating parasite known as New World screwworm has been confirmed in a Maryland resident, the first in the United States in years, according to U.S. and state health officials.

Health officials confirm that a Maryland resident was diagnosed with New World screwworm earlier this month after traveling to El Salvador. It has been declared the first human case in the United States by the Centers for Diesease Control and Prevention.