New Mexico agriculture officials have expanded surveillance efforts following the detection of a second case of New World screwworm in the state. The recent case, confirmed Thursday, involves a horse in Grant County, according to the New Mexico Livestock Board.
State Veterinarian Dr. Samantha Holeck said the agency is accelerating inspections and monitoring around the affected area to identify any further infections. The enhanced measures include a mandated inspection and, if necessary, treatment of animals within a 12.4-mile radius of the infected horse, designated as an infested zone.
New World screwworm is a parasitic fly larva known for feeding on living tissue. After being largely controlled in Central America for several decades, the pest has recently spread northward through Mexico. Its return to the United States was first recorded in early June with a case involving a calf in south Texas. Shortly afterward, a separate infection was confirmed in a dog in New Mexico’s Lea County. In response, the state has launched a dedicated website, ScrewwormNM.org, providing information and resources for reporting suspected cases.
The New Mexico Department of Agriculture emphasizes that regular movement of animals to auctions, veterinary appointments, fairs, and other routine activities will not be restricted unless authorities identify situations posing higher risk of spreading the pest.
Coordination between the New Mexico Livestock Board and the New Mexico Department of Wildlife is ongoing to extend surveillance efforts to wildlife populations and monitor hunting activities. Officials urge hunters, animal owners, and the public to be alert for signs of screwworm infestation, which include wounds that fail to heal or worsen, the presence of maggots, foul odor from wounds, persistent licking or irritation by the animal, and other unusual behaviors around injury sites.
New Mexico Secretary of Agriculture Jeff Witte thanked livestock producers, veterinarians, pet owners, and other stakeholders for their cooperation and vigilance. He underscored the importance of early detection and prompt reporting to curtail further spread of the pest.
Meanwhile, the U.S. Department of Agriculture announced last week that despite the recent screwworm case, the opening of the cattle crossing at Santa Teresa is set to proceed on September 24 as planned. The crossing is a critical point for livestock trade and movement along the U.S.-Mexico border.
Officials continue to provide updates, maps of affected zones, and reporting tools through the state’s screwworm website to support containment and response efforts.