New World Screwworm Outbreak in US Reaches 16 Cases Across Texas and New Mexico

Jun 23, 2026

The United States is responding to a reemergence of the destructive New World screwworm, with 16 confirmed cases reported across Texas and New Mexico as of June 22, 2026. The flesh-eating parasite, which was eradicated from the U.S. decades ago, has prompted Texas Governor Greg Abbott to activate the State Emergency Operations Center. Authorities have established quarantine zones across multiple counties to restrict livestock movement, while the USDA has initiated sterile fly dispersal flights to disrupt the pest's reproductive cycle.

New World screwworm outbreak spread

▪Texas has recorded 15 confirmed cases of New World screwworm, while New Mexico has recorded one case in a dog.
▪The first New World screwworm case in the United States was reported on June 3, 2026, in Zavala County, Texas.
▪Mexico has reported more than 29,000 cases of New World screwworm since November 2024, with approximately 1,800 active cases.
▪A New World screwworm case in a goat was confirmed in Terrell County, Texas, on June 22, 2026, located 180 miles west of the initial Texas detection.
▪The United States has recorded 16 total cases of New World screwworm across Texas and New Mexico as of June 22, 2026.

Quarantine zones for livestock movement

▪The Texas Animal Health Commission has established quarantine zones across multiple counties to restrict the movement of warm-blooded animals.
▪Warm-blooded animals moving outside a Texas quarantine zone must undergo inspection and obtain an animal movement certificate from the Texas Animal Health Commission.

Sterile fly eradication response

▪Texas Governor Greg Abbott activated the Texas State Emergency Operations Center to support the state's response to the New World screwworm reemergence.
▪The U.S. Department of Agriculture has initiated sterile fly dispersal flights over Crockett County, Texas, to prevent the reproduction of wild screwworm flies.

Screwworm fly identification features

▪The New World screwworm fly is slightly larger than a housefly and its larvae feed on the living tissue of warm-blooded animals, unlike other maggots that feed on dead tissue.
▪The New World screwworm fly can be identified by its large orange or red eyes, yellow face, metallic blue or green body, and three stripes along its back.

Human infection prevention measures

▪The Texas Department of State Health Services recommends sleeping indoors or in screened shelters and wearing loose-fitting, long-sleeved clothing to prevent insect bites.
▪The Texas Department of State Health Services advises people to keep open wounds clean and covered to prevent New World screwworm infestation.