The U.S. Department of Agriculture confirmed a New World screwworm infection in a New Mexico horse on September 17, 2026, shortly before plans to reopen the Santa Teresa port to Mexican livestock. This follows the first U.S. equine case in Texas. While authorities attempt to manage the flesh-eating parasite's spread through sterile fly releases and import bans, illicit animal smuggling networks along the border present significant biosecurity risks that could threaten a $1.8 billion economic impact.
New World screwworm horse infections
- ▪A working ranch horse in Presidio County, Texas, was confirmed to have a New World screwworm infection on its hind limb in September 2026, marking the first U.S. equine infection of the 2026 outbreak.
- ▪A horse in Grant County, New Mexico, was confirmed to be infected with New World screwworm on September 17, 2026, marking the state's second confirmed case since June 2026.
- ▪As of September 17, 2026, the United States Department of Agriculture reported 50 confirmed cases of New World screwworm in the U.S. since June 3, 2026, with three cases remaining active.
- ▪Mexico's animal health agency, Senasica, has confirmed more than 2,000 equine cases of New World screwworm since the outbreak began in 2024.
Illegal livestock smuggling networks
- ▪United States Department of Agriculture Inspector-General John Walk stated that animal trafficking along the southern U.S. border has become more pronounced and represents a national security issue due to the risk of spreading screwworm.
- ▪Sheriff's deputies in Presidio County, Texas, intercepted a trailer near Redford carrying six smuggled horses that had crossed the Rio Grande illegally from Mexico, bypassing veterinary inspections.
- ▪Presidio County Sergeant Deputy Sheriff Jaime Sanchez stated that smuggled horses can sell for at least $30,000 on the black market, with smuggling operations in the area linked to the La Linea cartel.
US-Mexico livestock import restrictions
- ▪The Trump administration halted live animal imports along the southern U.S. border in 2025 to curb screwworm spread, but initiated a phased reopening by resuming imports through an Arizona port in August 2026.
- ▪The Texas Animal Health Commission restricted the movement of warm-blooded animals outside of designated infested zones in counties including Presidio and Jeff Davis to curb the spread of screwworm.
- ▪The United States Department of Agriculture prepared to reopen the Santa Teresa, New Mexico, port of entry to Mexican livestock imports on September 24, 2026, following a year-long ban.
Screwworm economic impact estimates
- ▪Experts estimate that a widespread New World screwworm outbreak in Texas could cost the state's economy up to $1.8 billion.
- ▪The U.S. ban on Mexican livestock imports in 2025 and 2026 tightened domestic cattle supplies and drove American beef prices to record highs.
Animal wound monitoring protocols
- ▪The US Equestrian Foundation advised horse owners to monitor their animals daily for wounds, foul odors, or maggots, and to keep wounds clean and covered to prevent screwworm infestations.
- ▪To control the screwworm population, the Trump administration launched a sterile fly dispersal facility in Edinburg, Texas, where sterile male flies mate with females to produce non-viable offspring.
Story comments
Loading comments…