First human flesh-eating screwworm infection reported in 60 years

The United States has reported its first human case of flesh-eating screwworm infection in more than six decades, according to the Centers for Disease Control and Prevention (CDC). The case, identified in Maryland in August 2025, involved a traveler returning from Central America, where an ongoing outbreak of the parasite has been spreading north since late 2023.

The patient was diagnosed with screwworm myiasis, a rare but dangerous condition where fly larvae burrow into and feed on living tissue. Health officials have stressed that the infection poses minimal risk to the general public, but the development has raised serious concerns among livestock experts, especially in cattle-heavy states like Texas.

What Is Screwworm Myiasis?

The New World screwworm (Cochliomyia hominivorax) is a parasitic fly that lays hundreds of eggs in open wounds of warm-blooded animals, including humans. Unlike regular maggots that consume decaying flesh, screwworm larvae dig deeper into healthy tissue using sharp, screw-like mouths, a behavior that inspired the parasite’s name.

This infestation, known as myiasis, can cause intense pain, significant tissue damage, and, in severe cases, death if left untreated. A single female fly can lay up to 3,000 eggs in her lifetime, making infestations difficult to control without medical intervention.

Symptoms of human infection include:

•    Wounds that do not heal or worsen over time
•    A feeling of movement under the skin or inside a wound
•    Visible maggots in sores
•    Foul odor from the infected area
•    Fever or chills from secondary infections

Treatment involves manually removing the larvae and thoroughly cleaning the wound. If detected early, recovery is typically straightforward.

Looking Ahead:

Although the Maryland infection is being treated as an isolated, imported case, experts warn that the detection is a stark reminder of the vulnerabilities in U.S. biosecurity systems.
For now, the risk to public health remains low, but the economic and agricultural stakes are high. With the parasite advancing northward, the situation is being closely monitored by authorities, as a resurgence of screwworms could have devastating consequences for America’s cattle industry.