New World screwworm confirmed in New Mexico horse before Mexico livestock imports resume

A horse in Grant County, New Mexico, was confirmed on Thursday to be infected with the New World screwworm (Cochliomyia hominivorax), the state’s Department of Agriculture announced. The animal, located near the Mexican border, exhibited typical symptoms of the parasitic fly, including open wounds infested with maggots, and is the second confirmed case in New Mexico since the species reappeared in the region earlier this year. State officials have initiated quarantine measures for the premises, are conducting a sweep of nearby livestock, and are coordinating with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) to implement treatment protocols and prevent further spread.

The confirmation comes just days before New Mexico is scheduled to resume livestock imports from Mexico, a move that had been on hold pending the outcome of recent health screenings. APHIS officials emphasized that existing surveillance and rapid‑response frameworks remain in place to monitor for additional infestations, and they reiterated that the importation process will continue under strict biosecurity guidelines. Ongoing monitoring will determine whether any adjustments to import protocols are required, while veterinarians treat the affected horse and advise nearby producers on preventive measures.