A traveler from El Salvador has been diagnosed with the terrifying flesh-eating parasite, New World screwworm, federal health officials said Monday — the first reported case in the US tied to travel to a country with a current outbreak.
The parasite — a type of fly — was discovered Aug. 4 in a person who had recently arrived in Maryland from from the Central American country where an outbreak is currently unfolding, according to the US Department of Health and Human Services.
Cattle ranchers in Texas have previously been on high alert for screwworm investions in their livestock.
Gov. Greg Abbott listens to US Secretary of Agriculture Brooke Rollins speak on plans to fight the New World screwworm at a news conference at the Capitol in Austin, Friday, Aug. 15, 2025. Houston Chronicle via Getty Imag“This is the first human case of travel-associated New World screwworm myiasis (parasitic infestation of fly larvae) from an outbreak-affected country identified in the United States,” a HHS spokesperson said in a statement.
Officials haven’t released any additional details on the infected person, their condition or how the case was detected.
The HHS spokesperson added, though, that “the risk to public health in the United States from this introduction is very low.”
Screwworms, which rarely infest humans, are a type of parasitic flies that can lay eggs in the wounds of any warm-blooded animal.
Once the eggs hatch, hundreds of screwworm larvae can then horrifyingly bury through living flesh.
Cattle are detained in the pens of the Chihuahua Regional Livestock Union, at the Jeronimo-Santa Teresa border crossing in Ciudad Juarez, Mexico, on Nov. 27, 2024. Anadolu via Getty ImagesThe pests, which were largely eradicated from the US back in the 1960s, get their name because the post-hatching feeding frenzy has been likened to a screw being driven into wood.
If left untreated, a screwworm infestation – which the Center for Disease Control and Prevention describes as “very painful” — can eventually kill its host.
Treatment usually involves the painstaking removal of the larvae and then the disinfection of the wound.
Cattle ranchers and beef producers have already being on high alert for a possible outbreak in the US ever since the pests started traveling through Mexico from Central America in 2023.
Mexico reported a new case in cattle roughly 370 miles south of the US back in July – forcing the United States Department of Agriculture to ban livestock trade through southern ports of entry.
The USDA has previously predicted that a screwworm outbreak could set the economy in Texas, which is the biggest cattle-producing state in the US, about $1.8 billion in livestock deaths, labor costs and medication expenses.
The government’s confirmation of a screwworm case comes just over a week after US Department of Agriculture Secretary Brooke Rollins traveled to Texas to announce plans to build a sterile fly facility there as part of efforts to combat the pest. Anadolu via Getty Images
The USDA has estimated a screwworm outbreak could cost the economy in Texas, the biggest US cattle-producing state, about $1.8 billion in livestock deaths, labor costs and medication expenses. Anadolu via Getty ImagesNews of the detection comes just over a week after Agriculture Secretary Brooke Rollins traveled to the Lone Star state to announce plans to build a sterile facility amid efforts to combat the parasite.
The Maryland Department of Health didn’t immediately respond to requests for comment regarding the case.
With Post wires
