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

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.

“This is the first human case of travel-associated New World screwworm myiasis (parasitic infestation of fly larvae) from an outbreak-affected country identified in the United States,” HHS spokesperson Emily G. Hilliard told NBC News in a statement.