New Mexico state and federal officials this week expressed concern about the encroachment of a parasitic fly into the state, even as federal officials in March unveiled a flurry of efforts to combat the insect’s spread.
The New World screwworm, aptly named for the maggot’s behavior of burrowing into flesh and causing serious if not fatal wounds, often in animals, advanced northward through Mexico last year after being mainly contained in Central America. Before U.S. officials declared it eradicated in the 1960s, the wounds from parasites would kill wild and domestic animals, sometimes at a rate of one in five animals in an infected herd.
Since December 2025, federal data has documented more than 18,000 cases of screwworm infestations, mostly in Mexican livestock, according to federal data, including in cases within 70 miles south of Texas.
While currently no cases of the parasite have been found in the U.S. from the ongoing outbreak in Mexico, federal agriculture officials warned in January of 2025 that a new infestation could cause $1.9 billion in damages to Texas cattle alone.
As such, federal officials have announced several efforts to keep the parasite out of the U.S., including the expansion of a new facility to produce sterile flies in Moore Air Base in Edinburg, Texas, which the U.S. Department of Agriculture announced earlier this month.
Since the flies have a short lifespan, sterile male flies released into the population can significantly curb screwworm numbers by ensuring eggs go unfertilized. Federal officials said the facility will break ground in the spring and produce 100 million sterile flies per week starting by November 2027 and release them into the U.S.-Mexico border.
Additionally, the U.S. Food and Drug Administration approved a topical insecticide for emergency use in pets, livestock and birds.
Samantha Holeck, the state’s veterinarian for the New Mexico Livestock Board, said both the sterile fly facility and the insecticide are “vital,” but said she thinks “it’s inevitable” the screwworm will arrive in New Mexico. “Geographically, it’s going to be really hard to prevent it from entering the U.S. even though there have been a lot of really wonderful efforts put in place in Mexico to slow it down,” she said.
With the northward spread to within several hundred miles of the border, the U.S. Department of Agriculture shut down livestock crossings in July last year, and state agriculture officials said that will not change any time soon.
“There are no immediate plans to re-open southern ports of entry,” New Mexico Department of Agriculture Public Affairs Specialist Jennifer Green told Source NM in a statement.
For the bi-national cattle crossing in Santa Teresa, continued closure may mean the end of business, and that has upended import business and cost the port more than $1 billion.
“I had more than 30 employees, I have five now,” Daniel Manzanares, the director of the Unión Ganadera Regional De Chihuahua Co-op crossing, told Source NM. “I figure another six months, then we’ll shut down completely.”
U.S. Rep. Gabe Vasquez (D-NM), whose 2nd Congressional District includes the border, told Source NM that he wants to see more communication from federal agriculture officials “before the outbreak reaches” New Mexico.
“Our border stockyards are struggling, we’re losing revenue, and our domestic beef supply is at risk because of this outbreak,” Vasquez said in a statement provided to Source NM. “It’s vital that USDA, Congress, and our state partners are all on the same page to maximize the eradication of the NWS and prevent its spread to border states like New Mexico.”
Vasquez said “many ranchers” in his district “have expressed frustration at the lack of communication from USDA, including the lack of timely updates about the spread of the disease and lack of transparency around production at the sterile fly facility in Texas.”
A USDA spokesperson said in a statement to Source NM that the agency “will take all necessary steps to protect our country from foreign pests and diseases that threaten our economy and way of life. Along with our Federal, State and private sector partners, we are working every day to ensure our American agricultural industry is safe, secure, and resilient.”
