USDA Confirms New World Screwworm Case in Northern Mexico, 62 Miles from Texas Border

S. Department of Agriculture confirmed a New World screwworm case in the Mexican state of Nuevo León, approximately 62 miles from the Texas border. This marks the northernmost active case in Mexico. Federal health officials reported on Monday that cases of the flesh-eating parasitic infection continue to be detected near the United States.

U.S. remains very low. S. S. border. New World screwworm is a species of parasitic fly that feeds on live tissue and can cause myiasis, which is an infestation of larvae or maggots. It can infest livestock, pets, wildlife, and in rare instances, humans.

A female New World screwworm will lay between 200 and 300 eggs in an open wound of a living host. After eggs hatch, the maggots burrow further into the tissue and cause painful infestations. After feeding for about seven days, larvae drop to the ground, burrow into the soil, and emerge as adult screwworm flies.

New World screwworm is present in countries in Central and South America as well as the Caribbean. S. Symptoms of New World screwworm infection include skin lesions that don't heal or worsen over time, painful wounds or sores, bleeding from open sores, feeling or seeing maggots in wounds, or a bad odor from the site of the infestation.

There is currently no drug-only cure for New World screwworm infestation. Patients should contact a health care provider immediately if they believe they may be infested or see and feel maggots in a wound or anywhere else in the body. A physician will have to remove the maggots, which may require surgery.

Patients should not try to remove or dispose of the maggots themselves. The Centers for Disease Control and Prevention warns not to throw live maggots in the trash or outside because it could lead to New World screwworm spreading in the area. S.

In 1966. S. S. eradicated screwworm in 1966, the country has been relatively free of the parasite aside from a 2017 outbreak in the Florida Keys. Last year, a case of New World screwworm was detected in a Maryland resident who had recently returned from travel to El Salvador.

Agriculture Secretary Brooke Rollins visited Texas last week for the groundbreaking of a $600 million facility to produce sterile flies and eradicate New World screwworm. Once completed, the facility will produce 300 million sterile flies each week. The facility will not be fully built until 2028.

The article was published by Mary Kekatos and Dr. Crystal Joseph on April 22, 2026, at 5:01 PM. "These maggots actually feed on the tissue in the wound ... and they can destroy that tissue very substantially," Dr.

William Schaffner, a professor of preventive medicine at Vanderbilt University Medical Center in Nashville, told ABC News. "And it's as though they bury themselves. " "It can cause deadly wounds in animals," Dr.

Todd Ellerin, chief of infectious diseases at South Shore Health in Massachusetts, told ABC News. "So, it can kill cattle, kill livestock. ... Rarely, it can lay an egg in human wounds that can then become secondarily infected with bacterial infections and cause kind of severe infections.

" "There are no antibiotics or medications that one can get to attack the larvae, so often the treatment really is surgical," Dr. Marcus Pereira, medical director of the transplant infectious diseases program at NewYork-Presbyterian/Columbia University Irving Medical Center, told ABC News. "You have to remove the larvae and the wound along with it.

" Experts told ABC News that anyone traveling to parts of the world where New World screwworm infestation is common should keep any open wounds covered and use an insect repellent approved by the Environmental Protection Agency. People who are spending time outdoors should wear loose-fitting, long-sleeved shirts and pants, hats and socks, according to the CDC.

Schaffner said sterile male flies that can't impregnate females were created in a laboratory.

"And you made millions of these sterile male flies, and then you released them in nature," Schaffner said. "They mate with the females. The females mate only once. The females do not become pregnant and so they don't produce any eggs.

" Schaffner added this is also more ecologically sound than using pesticides, which can harm other species or plants. "The screwworm likes hot, kind of moist environments," Ellerin said. " Dr. Marcus Pereira told ABC News that a wound that smells worse, is bloody, is experiencing discharge or causing more pain could be a sign of an infestation.

U.S. currently. "This is principally an issue regarding livestock," Schaffner said. "The occasional human can become infested. " Crystal Joseph, MD, MS is an anesthesiology resident at Beth Israel Deaconess Medical Center/Harvard Medical School and a member of the ABC News Medical Unit.

@ABC reported these details in their coverage of the ongoing detections.