In a rare and concerning development, the first human case of the New World screwworm parasite in decades has been confirmed in the United States. The Centers for Disease Control and Prevention (CDC) and Maryland health officials confirmed the diagnosis on August 4, 2025, in a patient who had recently traveled to Central America. Travelers and health-conscious readers should be aware of the risks, symptoms, and potential treatment costs for this rare but dangerous parasite.

🪱 What Is the Screwworm?

The New World screwworm (Cochliomyia hominivorax) is a parasitic fly whose larvae are known for burrowing into and consuming living flesh of warm-blooded animals, including humans. Its Latin name literally translates to “man-eater.”

Although the parasite was eradicated from the U.S. in the 1960s through a sterile insect program, its re-emergence in Central America and Mexico has raised concerns about potential reintroduction to U.S. livestock and human populations.

The Confirmed Case

The Maryland resident has since recovered. Health officials emphasized that risk to the general public remains very low, and there is no evidence of transmission to other people or animals from this case. This infection is considered travel-associated.

Symptoms and Treatment

Screwworm infestations are painful and serious. Symptoms can include:

  • Unexplained wounds or sores that do not heal or worsen over time
  • Visible maggots in or around a wound
  • A sensation of movement under the skin
  • Foul-smelling discharge from the wound
  • Secondary bacterial infections causing fever or chills

If you notice these signs, seek medical help immediately.

Treatment involves manual or surgical removal of all larvae from the infested tissue by medical professionals. The CDC advises against attempting removal yourself. Suspected cases should be reported immediately to local and state health authorities.

⚠️ Travelers note: Treatment can be costly — sometimes hundreds to thousands of dollars. Travel insurance and telemedicine consultations are highly recommended for those visiting regions where the parasite is present.

Why It Matters

While human cases are rare, the re-emergence of the screwworm poses a significant threat to the U.S. livestock industry. Authorities are ramping up prevention efforts, including plans for a new sterile fly production facility in Texas, to prevent the parasite from establishing a foothold in cattle herds.

Travelers to Central America and Mexico should practice wound care vigilance, avoid contact with untreated wounds, and consider medical coverage for emergencies.