.FLESH-EATING CREATURESParasitic Diseases Researcher Talks “Flesh-Eating” Screwworm Infection After First Confirmed Human Case in U.S.
True to its name, the flesh-eating screwworm larvae do indeed thrive on mammalian (human included) tissue, says Lori Ferrins, who studies neglected parasitic diseases.
Public health officials in the U.S. say that a Maryland man is the first person to be infected by a “flesh-eating” parasite native to Central and South America.
The first documented “travel-associated” case of New World screwworm myiasis was confirmed by the Centers for Disease Control and Prevention and the Maryland Department of Health on Aug. 4, and health officials note that risk to public health posed by the infection is “very low.”
Lori Ferrins, associate professor of pharmaceutical sciences at Northeastern, who studies neglected parasitic diseases, explains that the infection is caused by an infestation of larvae from the screwworm fly.
“It’s not very common to see an infection among humans,” she notes. “It’s also incredibly painful if you’re infected.”
True to its name, the flesh-eating parasite does indeed thrive off of mammalian (human included) tissue. Ferrins notes that infection typically occurs when a screwworm fly lays its eggs in an open wound, resulting in larvae that literally burrow down into the flesh.
In an infected patient, this can result in painful tissue damage and potentially serious complications if left untreated.
“The fly will land on an open wound — like a cut or something — and then lay eggs,” she says. “And when the eggs hatch, that’s when the infection begins.”
Because of the nature of the infection — a festering open wound that is persistently bleeding — patients are susceptible to secondary infections or complications, Ferrins says.
“Oftentimes you’ll get secondary bacterial infections, which exacerbate the situation,” she says. “At that point, you have multiple competing infections, which further complicates your ability to receive treatment.”
“Unless you are actively traveling in one of the impacted areas, and spending time amongst livestock — because this is a disease that typically impacts animal populations — or sleeping outdoors in a community where there is active infection — there is very little risk of human infection,” Ferrins says.
A spokesperson for the Maryland Department of Health said the individual — a resident of Maryland — has recovered from the infection.
It’s not the first time that New World screwworm myiasis has menaced North America.
“We did have screwworms in 1966 — and also in the Florida Keys in 2017,” she notes. “And it’s been eradicated on both occasions previously, so there are steps that can be taken to address this.”
The effort to eradicate screwworm infections was led by the Screwworm Eradication Program, a pest control initiative developed by the Animal and Plant Health Inspection Service (APHIS) of the U.S. Department of Agriculture (USDA).
Officials would control infestations by sterilizing male flies that mate with wild screwworm female flies, which in turn prevented screwworm reproduction. Sterile flies are produced in large facilities, then dispersed over affected areas via “specially equipped planes,” according to the program’s website.
The USDA this month outlined a series of steps, including the construction of a sterile fly production facility in Texas, to help protect against infestation.
“NWS is a devastating pest,” the announcement notes. “When NWS fly larvae (maggots) burrow into the flesh of a living animal, they cause serious, often deadly damage to the animal. NWS can infest livestock, pets, wildlife, occasionally birds, and in rare cases, people. It is not only a threat to our ranching community — but it is a threat to our food supply and our national security.”
Also this month, the Food and Drug Administration granted an emergency use authorization for animal medications aimed at treating or preventing screwworm infestations, according to ABC.
Tanner Stening is Northeastern Global News reporter. The article was originally posted to the website of Northeastern University.
