The flesh-eating parasites that burrow into the living tissue of their victims have spread beyond Texas and are now moving through a second US state.
The US Department of Agriculture has confirmed the first case of New World screwworms in New Mexico, raising the total number of cases in the US to five.
Officials said the parasites were discovered in a dog which lives in Lea County, New Mexico, which sits right along the state’s eastern border with Texas.
The New World Screwworm (NWS) lays hundreds of larvae in the wounds of animals and people, which hatch within hours and start consuming the victim’s flesh.
These infestations can lead to deep, painful wounds that become infected and often result in death if left untreated.
Four cases have already been reported in Texas over the last week after the parasites were feared to be moving north from Mexico in 2025.
USDA said in a statement: ‘This situation is evolving, and we expect new information to emerge as our investigation continues.’
‘We are working closely with our partners in New Mexico, Texas, and across the region to ensure we identify, contain, and respond to any potential cases as swiftly as possible.’
The New World Screwworm has been confirmed in New Mexico by the US Department of Agriculture
A terrifying flesh-eating parasite has invaded the US for the first time since 1966
While the first cases detected in the US this year have all involved animals, including three calves, thousands of cases in people being infected with NWS have been confirmed in Mexico and Central America this year.
The CDC has found more than 2,100 human cases of NWS infestations as of June 8.
To protect yourself in areas where New World screwworm flies are present, the CDC recommends keeping all open wounds clean and covered, even if they are only small cuts.
You should also wear loose-fitting long sleeve shirts, pants, hats and socks to minimize exposed skin. Additionally, the CDC said to use EPA-registered insect repellent and sleep indoors or in screened rooms.
Early symptoms of a screwworm infection include unexplained painful wounds or sores that do not heal, a foul-smelling odor or bleeding from the site or seeing and feeling maggots or movement in a wound or around the nose, mouth, eyes or ears.
The screwworm was first discovered in the US in a three-week-old calf last week in Texas, and a second case was found only miles away in a young calf a day later.
Three Texas counties, including Kinney, Jim Hogg and Uvalde, have already declared local states of disaster in response to the New World screwworm threat, while similar declarations are pending in Webb, La Salle and Val Verde counties.
Some county leaders have called on President Donald Trump to issue a national emergency declaration, arguing that communities on the front lines need additional personnel, funding and resources to prevent the pest from gaining a foothold in the US.
Female New World Screwworms can lay over 300 eggs in the open wounds of animals and humans, which hatch within 24 hours and begin eating the victim’s tissue
One year ago, officials in Mexico discovered several NWS cases in the country’s southern states of Chiapas, Oaxaca, and Veracruz – all of which were part of the migrant caravan route used by millions to cross the US border illegally over the last decade.
Researchers have feared there may be no way of stopping the flies at the US-Mexico border, which could start infesting the South within two decades due to rising temperatures.
Research has indicated that states along the Gulf, including Texas, Florida and Louisiana, are all at risk of seeing the parasites potentially killing cattle and people by 2055.
Texas Governor Greg Abbott said in a statement: ‘The protection of our ranchers, livestock producers, deer breeders, and the Texas economy from this pest is a top priority.’
‘We have eradicated this pest before, and we will do it again in close cooperation with our federal partners. Texans should stay alert, check animals daily for wounds, and report any suspected cases immediately.’
When screwworms became a major problem in the US, it cost the US $200 million – roughly $1.8 billion today – in livestock.
The NWS was last detected in Texas 60 years ago.
The species was wiped out in the US by 1982 using a clever method of sterilizing male flies using radioactive gamma rays so they could not produce any offspring with the females.
