Health officials are sounding the alarm as a dangerous parasite inches closer to the U.S. border. The New World screwworm, a flesh-eating fly larvae long feared by farmers and doctors, has now been detected in Tamaulipas, Mexico, directly across from Texas. That proximity has triggered new warnings from federal and state agencies about the risk to people, pets, and livestock.
Days ago, the Centers for Disease Control and Prevention issued a health alert urging local health departments to be prepared to recognize and treat screwworm cases quickly. The parasite spreads when screwworm flies lay eggs in open wounds or in sensitive areas like the nose, ears, eyes, or mouth. Once the eggs hatch, the larvae burrow into living tissue and feed on surrounding flesh.
While livestock are the primary target, the CDC warns that any warm-blooded animal, including humans and household pets, can be affected. People who spend time outdoors, work with animals, or have untreated cuts and scrapes face a higher exposure risk, especially in regions where the flies are active, such as parts of Mexico and Central America.
Treatment requires the complete removal of all larvae and eggs. In severe cases, surgery may be necessary. Without treatment, infections can turn fatal.
The U.S. has spent decades keeping screwworms at bay through sterile fly release programs, a strategy that helped eliminate the parasite from the Florida Keys in 2017. Still, the current outbreak is growing fast, with 1,190 human cases and seven deaths reported, alongside more than 148,000 animal infections.
“It’s just plain cowboy logic — when you’re seeing this many cases, this fast, it tells you there may be established screwworm fly populations in Tamaulipas,” Texas Agriculture Commissioner Sid Miller said in a statement to Border Report. “We’re grateful sterile fly deployment has begun, but make no mistake: Texas producers need to stay on high alert along our border.”
As the parasite creeps north, the cattle industry warns that an unchecked spread could cost billions and put both animals and people at serious risk.
