Flesh-Eating ‘Screwworm’ Scare Reaches The U.S

New fear unlocked: the flesh-eating maggot that happily burrows inside livestock, wildlife, and yes, even humans, eating its prey from the inside out a little too close to home, especially for Texans.

The New World screwworm is a type of fly that feeds off wounds — and a potential case in South Texas is now being tested at the National Veterinary Services Laboratories in Iowa.

“We have already activated personnel on the ground and are working with local partners,” the Department of Agriculture announced Wednesday.

A case of NWS may have been detected in South Texas. The sample is now at USDA’s National Veterinary Services Laboratories (NVSL) in Ames, lowa for confirmatory testing. We will provide updates the moment results are available.

We have already activated personnel on the ground…

— Dept. of Agriculture (@USDA) June 3, 2026

The potential U.S. case comes after the screwworm was found last week in a 5-year-old goat in Coahuila, the Mexican state that borders southwestern Texas. A separate case was reported on Sunday of the screwworm infecting a dog in Tamaulipas, another bordering Mexican state. As of Monday, the USDA is tracking 1,981 active animal cases in the country.

The current outbreak in Mexico has gone on for a while, which caused Secretary of Agriculture Brooke Rollins to shut down livestock trade across the southern border in July 2025. There was one confirmed U.S. case last year from a person who returned to Maryland after traveling to El Salvador.

Adult screwworm flies are the size of a housefly, with orange eyes, a metallic blue or green body, and three dark stripes along their backs. The parasite is typically found in South America and parts of the Caribbean, but has been found farther north, in Central America and Mexico, over the last three years. While the outbreak in Mexico and Central America is primarily in livestock, wildlife, and pets, there have been cases in people, according to the CDC.

The agency reports the screwworm maggots cause painful, foul-smelling wounds — and that sometimes maggots can be seen or felt in open wounds or in parts of the body with openings, including nose, mouth, eyes, ears, and genitals.

If the infestation isn’t caught early and treated quickly, it can lead to extensive tissue damage and sometimes death.

The CDC advises keeping any open wounds clean and covered, no matter the size or location on the body. Wear loose clothing, long-sleeved shirts and pants, hats, and socks to limit skin exposure. Other preventive measures include using an EPA-registered insect repellent, treating clothes with products containing 0.5% permethrin, and sleeping indoors when able.

If mammals or birds are found to be showing signs of irritated behavior, head shaking, decaying smell, or maggots in wounds, they should be reported to an animal health official immediately.

The USDA is reporting any new “screwworm” cases within 400 miles of the U.S. border on its map tracker every Tuesday and Thursday, and new cases within 100 miles are being tracked daily.