First U.S. Case of Flesh-Eating Parasite Confirmed in Maryland Traveler from El Salvador

By Jerry Williams

WASHINGTON — U.S. health officials have confirmed the first human case of a flesh-eating parasite known as New World screwworm (NWS) myiasis, after a patient returning from El Salvador was diagnosed earlier this month.

The U.S. Department of Health and Human Services (HHS) announced Monday that the Centers for Disease Control and Prevention (CDC) and Maryland’s health department worked jointly to investigate the case, which was confirmed on 4 August.

The parasitic fly larvae — or maggots — burrow into living tissue, causing severe and potentially fatal infections. Though the screwworm typically affects livestock, it can also infest pets, wildlife, birds, and in rare cases, humans, particularly those with open wounds.

“This is the first U.S. human case linked to an outbreak-affected country,” said HHS spokesperson Andrew Nixon, referring to El Salvador. The screwworm has now been detected in every Central American country, including Mexico, despite containment efforts.

While the risk to the general public remains very low, officials urge travelers to high-risk areas — especially rural zones with livestock — to take precautions.

The USDA warns that a livestock outbreak could inflict over $100 billion in economic damage, threatening the cattle and livestock sectors. In response, the USDA’s Animal and Plant Health Inspection Service has partnered with U.S. agriculture agencies, the State Department, and the UN Food and Agriculture Organization to monitor and contain the spread.

Screwworm myiasis, though rare in humans, poses a serious threat when not treated quickly. The larvae feed on living flesh, unlike common maggots which consume dead tissue, making infestations painful and potentially deadly.