NEW YORK — A person who traveled to El Salvador has been diagnosed with New World screwworm — the first reported U.S. case tied to travel to a country with a current outbreak.

The Centers for Disease Control and Prevention confirmed the diagnosis on Aug. 4. Federal health officials acknowledged the infection in an emailed statement Monday, but did not describe the patient’s condition. They collaborated with Maryland health officials, the statement said.

New World screwworm is a fly that lays its eggs in open wounds and body opening such as the eyes, ears, nose or mouth. It primarily affects livestock and is rare in humans. It does not spread from person to person, and poses a very low risk to the public, according to U.S. health officials.

The parasite has been a larger concern to ranchers, as cattle infestations have been moving northward through Central America and Mexico. The CDC is working with the U.S. Agriculture Department to prevent further spread, officials said.

The pest was a problem for the American cattle industry for decades until the U.S. largely eradicated it in the 1970s.

— Mike Stobbe