For the first time in history, an American has been infected with the flesh-eating parasite dubbed the “screwworm.” The patient, who resides in Maryland, contracted the parasite while travelling.

“The Maryland resident has recovered from the infection, and the investigation confirmed there is no indication of transmission to any other individuals or animals. Currently, the risk to public and animal health in Maryland from this introduction is very low,” the Maryland Department of Health said in a statement to PEOPLE, adding that the resident “had returned from a country currently experiencing a NWS outbreak.”

NWS is short for New World Screwworm, which is actually caused by a fly. Although humans are susceptible to the parasite, livestock are its primary host, and the screwworm can kill a cow in two weeks.

Screwworm is actually a fly that gets its name from how its larva infects a host. It’s a “flesh-eating parasite,” Colin Woodall, CEO of the National Cattlemen’s Beef Association, told NPR. As he explained, the fly lays its eggs on livestock, like cattle. Then, he says, “the larva does exactly what the name would suggest. It screws or bores into the flesh of our cattle and, in essence, eats the animal from the inside out. It is a horrific parasite.” – PEOPLE

The United States and Mexico have both invested in tackling the screwworm parasite, as it continues to infect cattle.

U.S. Makes $750 Million Investment In Tackling Screwworm

Entomologist Edwin Burgess explained to NPR that in his opinion, the only way to stop the screwworm is to drop millions of dollars in the form of sterile flies in the afflicted areas. It’s a way to “crash” the population of flies.

Scientists make the flies sterile through radiation, and then, “they take just the males, and then they package them up and fly them over large areas and drop these little packets out of planes. And then those adult male flies mate with the females,” which only mate once in their lifetime. The eggs are then all sterile and do not hatch.

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According to the U.S. Centers for Disease Control, a  screwworm infection is “very painful.” It causes unexplained but painful wounds or sores that worsen over time and may bleed.  Those infected may feel or see maggots moving in the wound. Treatment generally involves surgery to remove the worms in the infected area.