The New World screwworm has been confirmed in a horse in Grant County, New Mexico, just days before the Santa Teresa port— the largest U.S. entry point for Mexican live cattle—is scheduled to reopen on September 24.
USDA said the parasite, which infests open wounds of livestock, was detected on Thursday; Agriculture Secretary Brooke Rollins had earlier announced the port’s reopening as part of efforts to restore cross-border cattle trade that was paused during the outbreak.
Fifty screwworm cases have been recorded in the U.S. since early June, almost all in Texas, with three currently active; by contrast, nearly 2,000 cases remain active in Mexico.
Rollins emphasized that USDA would delay reopening if it were not “100% sure” about safety and protocols, though state officials indicated the new case is unlikely to stop the Sept 24 restart.
The Santa Teresa gateway handled about 40% of U.S. cattle imports from Mexico in 2024—nearly 500,000 head—making it a critical chokepoint for feedlot supply chains and related veterinary, transport, and insurance services.
New Mexico Cattle Growers Association president Tom Paterson said the horse case is not directly linked to port normalization but warned ranchers to remain vigilant with animal inspections.
USDA is also considering reopening a second port in Columbus, New Mexico, if containment continues to hold.
