Flesh-eating New World screwworm making a comeback in states surrounding Oklahoma

New World screwworm surges in states surrounding Oklahoma, threatening livestock again Advertisement Updated: 2:07 PM EST Nov 11, 2026 Editorial Standards ⓘ Kilee Thomas Reporter New World screwworm surges in states surrounding Oklahoma, threatening livestock again Updated: 2:07 PM EST Nov 11, 2026 Editorial Standards ⓘ Kilee Thomas Reporter A parasite once eradicated from the U.S. is now making a comeback. The New World screwworm has been detected in more than 120 animals since June, with November already seeing the highest number of cases yet. Those are numbers the U.S. hasn't seen in four decades, and the cases are in states surrounding Oklahoma. Advertisement As of Tuesday, there are no confirmed cases of screwworm in Oklahoma. While the colder temperatures may keep the flies away, experts said the biggest concern is the parasite hitching a ride in. "The last time we had case numbers anywhere near where we're at right now in the United States as a whole was in 1979," said Dr. Jonathan Cammack, the state extension specialist with Oklahoma State University. The tiny fly is posing a big threat to America's livestock. New World screwworm cases are surging in states surrounding Oklahoma. "Really, our concern is livestock," said Cammack. The flesh-eating parasite lays its eggs in open wounds, where the larvae feed on an animal's living tissue. Cases have been reported in Texas, New Mexico, and Arizona. So, could it spread further? Experts at Oklahoma State University told sister station KOCO 5 that cooler temperatures are working in Oklahoma's favor, but there's another way the parasite could cross state lines. "These flies can generally only fly 6 to 10 miles in the course of their life, but we can put cows in a trailer and drive them 600 miles in a day," said Cammack. Decades ago, the USDA fought back against the parasite by releasing sterile flies to stop reproduction and eventually pushing the parasite out of the U.S. and Central America. But in 2022, experts said the screwworm reappeared. They still don't know exactly what went wrong. "Something happened. We don't know if it was an illegal movement of livestock through or outside of that barrier zone, and then we've got cases 10 or 100 miles away from where we need to be looking," said Cammack. According to the USDA, cattle and sheep make up the majority of animals infested. More information about screwworms can be found on Oklahoma State's website . Make WGAL a preferred source on Google Add Preferred Source Share Infinite Scroll Enabled Top Picks Vietnam veteran honored with new truck, making it easier for him to go to medical appointments Missing baby in South Carolina found buried alive a day after authorities say his father took him Mother and two young children killed in Missouri crash after semitruck struck their minivan Donald Trump’s private message to Joe Biden emerges in new White House memoir