Health officials have confirmed the first human infection of a deadly flesh-eating parasite in the United States.

The New World screwworm was found in a person who had recently traveled back from El Salvador, according to the Maryland Department of Health and the CDC.

Andrew G. Nixon, spokesperson for the U.S. Department of Health and Human Services, told Reuters that the “risk to public health in the United States from this case is very low.”

While human infections are rare, the parasite is more dangerous for livestock and wildlife. The screwworm fly lays eggs in open wounds of warm-blooded animals. The larvae then burrow into living tissue, and without treatment, it can be deadly.

Treating the infection involves carefully removing the larvae and cleaning the wounds. The parasite is called a “screwworm” because it twists deeper into the tissue when disturbed, making it hard to remove.

The case has raised concerns in the U.S. cattle industry, as an outbreak could lead to huge economic losses. The Department of Agriculture estimates that a screwworm infestation in Texas could cost around $1.8 billion.

To prevent this, Agriculture Secretary Brooke Rollins announced plans to build a sterile fly facility in Texas. Sterilized male flies are released to reduce the wild population by preventing breeding. This method successfully wiped out screwworms in the U.S. about 60 years ago.

No animal infections have been reported in the U.S. this year, but scientists warn that rising global temperatures could allow the parasite to spread north from South and Central America.