Federal animal health records indicate the first known case of New World screwworm in a U.S. horse was confirmed this week in southern Texas near the Mexican border. The U.S. Department of Agriculture listed the case as identified on Wednesday in Presidio County.
The finding follows months of infestations in U.S. cattle that have heightened concerns about controlling the parasite, which feeds on living tissue. State authorities in Texas detected the equine infection and moved swiftly to limit animal movements.
The Texas Animal Health Commission issued an order on Wednesday that prohibits the movement of warm-blooded animals out of an officially designated "infested" zone encompassing portions of Presidio and Jeff Davis counties. The restriction is intended to reduce the risk of further spread within the local animal population.
Federal and state materials note that a prior outbreak of New World screwworm in the United States had resulted in the deaths of thousands of animals before the pest was declared eradicated in the 1960s. In Texas, where the year’s first U.S. cases were confirmed, experts cited in official communications estimate that a widespread outbreak could have an economic cost of up to $1.8 billion.
Reports in the media have flagged concerns that smuggled animals, including horses, may serve as hosts for New World screwworm, although authorities have not publicly addressed the provenance of the horse found infected in Presidio County. The USDA and Texas officials have not provided additional information on the origin of this specific case.
The U.S. Equestrian Federation, which organizes national equine events, said the newly discovered infestation was located in the hind limb of a working ranch horse and did not provide further identifying details. The organization recommended that horse owners make regular inspections of their animals.
In an advisory statement, the federation urged routine wound care, fly control and standard biosecurity practices for owners, saying these measures can help protect individual horses and the broader equine community.
Impacts and context
The confirmation of an infected horse comes amid ongoing efforts to contain earlier cattle cases. The state movement ban targets warm-blooded animals within the specified infested zone in Presidio and Jeff Davis counties as a containment measure. Officials have emphasized inspection and preventive care among horse owners.
At this time, authorities have limited public details about how this horse contracted the parasite and whether the case represents isolated transmission or signals wider equine vulnerability in the area.