Horse in New Mexico infected with screwworm before Mexico livestock imports resume

New Mexico Horse Tests Positive for New World Screwworm Near Border

Provpnadvice.com – A horse in southwestern New Mexico has been confirmed with New World screwworm, adding a new concern just before livestock imports from Mexico are scheduled to resume through the Santa Teresa port of entry.

The infected animal was located in Grant County, close to the Mexican border, the U.S. Department of Agriculture said Thursday. It marks New Mexico’s second confirmed detection since the flesh-eating parasite entered the United States from Mexico in June.

The development arrives as the federal government prepares to reopen the Santa Teresa crossing to livestock shipments on Sept. 24. Agriculture Secretary Brooke Rollins announced the planned reopening during a Thursday news conference in Santa Teresa. At the time of that announcement, the New Mexico Department of Agriculture had not yet confirmed the horse’s infection.

Livestock Crossing Set for Phased Return

Livestock imports at the southern border were halted by the Trump administration last year as officials worked to limit the spread of New World screwworm. The restrictions affected cross-border animal movement while federal and state authorities monitored the parasite’s return.

Imports began returning last month through an Arizona port of entry under what USDA has described as a phased reopening. The planned reopening at Santa Teresa would extend that approach to a key New Mexico border crossing, though the newly confirmed case underscores the continuing need for surveillance around transported animals and areas near the border.

The timing places additional attention on animal health checks as cross-border trade resumes. Ranchers, horse owners, livestock handlers and veterinarians may be especially alert for wounds that could allow flies to deposit larvae. Early identification matters because the infestation can become dangerous when it is not treated promptly.

Fifty U.S. Cases Tracked Since June

USDA has documented 50 confirmed U.S. cases since the current outbreak was first identified on June 3. Its online dashboard showed that only three cases remained active as of Thursday.

Four cases were logged in August, all of them in Texas. Two have been identified so far this month: one in Texas and the newly confirmed New Mexico case. The pattern illustrates why officials continue to track detections across the southern border region even as some livestock crossings reopen.

New Mexico’s location makes border monitoring particularly significant. Grant County sits in the state’s southwestern corner, where movement of animals, people and goods occurs within a broader region connected to Mexico and neighboring U.S. states. A case in a horse does not mean every nearby animal is infected, but it does signal the importance of checking susceptible animals for symptoms and responding quickly when concerns arise.

How New World Screwworm Affects Animals

New World screwworm is not an ordinary nuisance fly problem. Infestations develop when fly larvae enter an open wound on a warm-blooded animal and feed on living tissue. Horses, cattle and other animals can be affected when wounds are left exposed.

The parasite can cause severe harm if an infestation goes untreated. Because the larvae consume live tissue, affected wounds may worsen rather than heal normally. Fast veterinary attention is important when owners see unusual wound activity or signs that an animal is in distress.

Routine wound care can therefore play an important role for animal owners in areas where screwworm activity is being monitored. Inspecting injuries, keeping wounds clean and seeking professional guidance when something appears abnormal are practical steps that can help identify potential problems sooner.

The confirmed New Mexico horse case also highlights that surveillance is not limited to cattle. Horses and other warm-blooded animals can be vulnerable when the conditions for infestation are present. Detection in any species can help authorities understand where the parasite is appearing and where control efforts may need to focus.

Human Risk Remains Very Low

Public health officials have emphasized that the danger to people remains limited. The Centers for Disease Control and Prevention has characterized the risk of human infestation as very low, and no human cases have been reported.

“Very low”

Even so, the livestock and animal-health implications are substantial because untreated infestations can be fatal to animals. The concern is not simply the presence of flies, but the possibility that larvae may establish themselves in open wounds and damage living tissue.

As Santa Teresa approaches its planned reopening date, the latest confirmation reinforces the balance federal and state officials are trying to maintain: restoring livestock trade while continuing aggressive monitoring for a parasite capable of causing serious animal losses. The small number of active U.S. cases is encouraging, but the New Mexico detection shows that vigilance remains necessary along the border.