First U.S. Horse Case of New World Screwworm Confirmed in Texas; Animal-Movement Zone Imposed

What is confirmed—and what is not

Reuters reported the equine detection at 5:30 p.m. Pacific on September 10 after reviewing USDA case data. The parasite had already been confirmed in other U.S. animals during the 2026 incursion, so this is the first confirmed horse case in the current outbreak—not the first U.S. animal case of the year.

Texas officials detected the case and on September 9 restricted movement of warm-blooded animals out of a designated zone in Presidio and Jeff Davis counties. The available sources do not establish how the horse became infested, and officials have not linked the case to animal smuggling or any identified person.

No source reviewed for this report announces a New World screwworm detection in California, a Kern County quarantine or a new nationwide animal-movement shutdown. Horse and livestock owners should not treat a Texas zone order as a California restriction, but they should follow official prevention and reporting guidance.

Why animal owners are being told to inspect wounds

USDA describes New World screwworm as a parasitic fly whose larvae feed in wounds of living, warm-blooded animals. Infestations can affect livestock, pets, wildlife, birds and, rarely, people; untreated cases can cause severe tissue damage and death.

Federal guidance tells owners to watch for irritated behavior, head shaking, a smell of decay and larvae in wounds. It also recommends prompt wound care, fly control, removing sharp hazards from pens and equipment and protecting animals from other wound-causing parasites.

Anyone who suspects an animal infestation should contact a veterinarian and animal-health officials immediately rather than attempting a home diagnosis. USDA says treatment should follow a veterinarian's recommendations. Suspected human infestation requires prompt medical care.

Food safety and public risk require careful language

USDA's unified response page says screwworm is not a food-safety issue and describes the current risk to U.S. animals and people as very low. That page was last modified September 4, before the equine case was reported, so its risk assessment should be read alongside the newer detection rather than used to erase it.

The parasite can infest people, but an infected animal does not mean routine person-to-person spread. The immediate concern is identifying and treating wounds, controlling fly reproduction and preventing affected animals from carrying the pest beyond restricted areas.

California owners do not need to panic or assume a local outbreak. They do need to avoid rumors, inspect animals carefully, consult veterinarians about suspicious wounds and rely on USDA and state animal-health authorities for any change in local movement rules.

About the image

The featured image is an authentic January 2017 macro photograph of an adult New World screwworm fly taken by Judy Gallagher at the National Key Deer Refuge in Florida. Wikimedia Commons verified the photograph's Creative Commons Attribution 2.0 license.

The file photograph shows the species at the center of the alert. It does not depict the infected horse, a wound, Presidio County, the September 2026 detection, animal-health personnel or evidence from the current response, and its use does not imply the photographer's endorsement.