The U.S. Department of Agriculture (USDA) confirmed a new case of New World screwworm in Texas on Monday. This development raises concerns in controlling the flesh-eating parasite. The screwworm, with larvae that feed on the tissue of warm-blooded animals, had been eradicated in the U.S. decades ago using a sterile-fly release program.

Current Situation

Increased monitoring and response measures are ongoing in the affected U.S. regions. The USDA’s screwworm rapid response account announced that the new case was found in a goat. The parasite infested a castration site wound and does not affect healthy skin. This detection is roughly 180 miles west of the initial Texas case and 74 miles west of the nearest confirmed case. Mexico has reported nearly 30,000 cases since November 2024, with 1,800 still active. The U.S. currently reports 16 cases.

According to a USDA screwworm dashboard, U.S. cases have involved cattle, sheep, goats, and one dog. The latest case was confirmed in Terrell County, Texas, with a previous case confirmed in Edwards County, Texas. In New Mexico, there is one inactive case involving a dog.

Ranchers and animal health experts remain concerned due to screwworm detections in North and Central America. Response teams are conducting inspections, outreach efforts, and using sterile insect techniques that historically help reduce screwworm populations. Officials encourage livestock owners to promptly report suspicious wounds and infestations.

Threat of New World Screwworm

The New World screwworm poses a threat to livestock, wildlife, pets, and occasionally humans. Federal and state authorities aim to identify more cases and monitor animal movements to limit further spread.

Understanding New World Screwworm

According to the U.S. Centers for Disease Control and Prevention, the New World screwworm is a fly laying eggs in open wounds or body openings such as eyes, genitals, nose, or mouth. The hatched parasitic maggots consume the animal’s living tissue.

History of Screwworm in the U.S.

The New World screwworm was once common in the Southern U.S., causing significant losses for livestock producers. Through a program releasing sterile male flies, federal and state officials eradicated the pest, achieving zero cases by 1982.

Current Outbreak Locations

The ongoing New World screwworm outbreak is concentrated in parts of Mexico and Central America. In the U.S., current cases are confirmed in Texas and New Mexico as of Monday.