A rare and alarming case of a flesh-eating parasite has been confirmed in the United States, marking the first occurrence in decades. The patient, a woman from Maryland, had recently returned from Central America, where she likely encountered the New World screwworm fly, scientifically known as Cochliomyia hominivorax. Fortunately, the woman has recovered, and the US Department of Health and Human Services has stated that the risk of further human transmission is “very low.”
While the immediate health risk appears limited, the presence of this parasite raises significant concerns about its potential impact on the agricultural sector and food security in the US. The larvae of the screwworm fly are notorious for infesting warm-blooded animals, feeding on their living tissue and potentially leading to severe infections.
Understanding the Threat of Screwworm Infections
Screwworm infections occur when the female fly lays its eggs in open wounds, around the navel, or near the eyes of animals. The resulting larvae then consume the flesh, which can cause devastating damage. According to infectious disease specialist Daniel Griffin, the maggots can transform “living tissue into Swiss cheese.” Without timely treatment, infections can be fatal.
Historically, screwworms primarily affected livestock, including cattle, horses, and pigs, although they can also infect pets and humans. The larvae act swiftly; in less than a week, they can kill a mature cow. A potential outbreak in Texas, the largest cattle-producing state in the US, could lead to losses of approximately $1.8 billion, according to the US Department of Agriculture.
Efforts to eradicate screwworms date back to the 1950s when authorities in the US and Central America implemented a control program involving the release of lab-bred sterile insects to mate with wild populations. These measures successfully reduced the incidence of infections, leading to the last reported endemic case in the US in 1982. Despite occasional cases brought back by travelers, the recent resurgence of the New World infection poses a renewed threat to public health and agriculture.
Global Impact and Collaborative Response
Since early 2023, Central America has witnessed a significant outbreak, with hundreds of reported human cases in Nicaragua and Costa Rica, some requiring urgent medical intervention. Ricardo Somarriba, director of Nicaragua’s Institute for Agricultural Protection and Health, emphasized the seriousness of the situation, noting that untreated infections could lead to severe neurological damage. “If those worms hadn’t been removed, they would have destroyed their brain,” he stated.
The case in Maryland serves as a stark reminder of the importance of international cooperation in controlling the spread of such dangerous infections. As the parasite continues its advance northward, vigilance and proactive measures will be essential in safeguarding both public health and the livelihoods of ranchers across the continent. The situation underscores the need for countries to collaborate on monitoring and managing the risks associated with infectious diseases.
