A Maryland resident has been treated for the New World screwworm, a rare flesh-eating parasite, after recently returning from Guatemala, according to health and agriculture sources cited by Reuters. This marks the first confirmed human case in the United States since the parasite began spreading northward from Central America and southern Mexico in late 2023.
Maryland Confirms Case
The case was shared with state veterinarians last week during a call with the US Centers for Disease Control and Prevention (CDC). While the CDC confirmed the infection, Maryland officials were responsible for releasing details.
The patient received treatment, and state health authorities implemented prevention measures. No further details have been disclosed due to privacy protections.
What Are Screwworms?
Screwworms are parasitic flies that lay eggs in wounds on warm-blooded animals. Once hatched, larvae burrow into living flesh, feeding in a twisting motion—similar to a screw turning into wood, which inspired their name.
The parasite primarily infects cattle and wildlife, but humans can also be affected. If untreated, infestations can be fatal. Treatment involves removing hundreds of larvae and disinfecting wounds, with early intervention typically preventing death.
Why the Screwworm Threat Matters
Screwworm infestations are devastating to livestock. The parasite was eliminated from the US in the 1960s using a sterile fly program. However, new cases spreading from Central America have raised concerns about a potential outbreak that could cost billions of dollars for the beef industry.
The US cattle herd is currently at its smallest size in 70 years, and beef prices are at record highs. An uncontrolled screwworm outbreak could heavily impact ranchers, the beef market, and food prices nationwide.
Government Response and Prevention Efforts
The US Department of Agriculture (USDA) is stepping up measures to stop the parasite’s spread. USDA Secretary Brooke Rollins announced plans to construct a sterile fly production facility in Texas, expected to take two to three years to begin operations.
Currently, the only active sterile fly plant is in Panama, producing 100 million sterile flies per week. Experts estimate that at least five times that amount would be needed to effectively push the parasite back into Central America. Mexico is also building a $51 million facility to combat screwworms.
