New Screwworm Case in Texas Sparks Concerns

U.S. agriculture officials have reported a new confirmed case of New World screwworm in Texas, raising concerns about efforts to control the flesh-eating parasite. The larvae of this organism feed on the living tissue of warm-blooded animals, and it was previously eradicated from the country through a sterile-fly release program.

The recently confirmed infection has led to increased surveillance and response measures in affected areas. In an update, the U.S. Department of Agriculture’s screwworm rapid response account disclosed that the new case was found in a goat. According to the post, the infestation occurred at a castration site wound, with the parasite affecting only open wounds rather than healthy skin. This detection is located approximately 180 miles west of the initial Texas case and 74 miles west of the nearest previous case.

Mexico has reported nearly 30,000 screwworm cases since November 2024, with 1,800 still active. In contrast, the U.S. has confirmed 16 cases. The USDA’s screwworm dashboard shows U.S. cases involving cattle, sheep, goats, and one dog. The recent Texas case was identified in Terrell County, while another was discovered in Edwards County. A separate case involving a dog in New Mexico is recorded as inactive.

“The New World screwworm poses a significant threat to livestock, wildlife, pets, and, in rare cases, humans,” officials warned, emphasizing the importance of identifying potential cases and monitoring animal movements to prevent further spread.

Federal and state authorities are urging livestock owners to report suspect wounds and infestations promptly. Response teams are amplifying inspections, public outreach, and containment activities, utilizing sterile insect techniques that have historically suppressed screwworm populations.

Understanding New World Screwworm

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

Screwworm History in the U.S.

Historically, the New World screwworm was prevalent throughout the Southern U.S., causing significant losses for livestock producers. To eliminate the pest, officials implemented a sterile-male fly release program, achieving zero cases by 1982.

Current Outbreak Locations

The present screwworm outbreak is concentrated in parts of Mexico and Central America, with the parasite gradually moving northward. In the U.S., confirmed cases are concentrated in Texas and New Mexico.