Screwworm fly detected in Texas decades after cattle threat was largely eradicated in U.S.

By — John Hanna, Associated Press John Hanna, Associated Press Leave your feedback Share Copy URL https://www.pbs.org/newshour/nation/screwworm-fly-detected-in-texas-decades-after-cattle-threat-was-largely-eradicated-in-u-s Email Facebook Twitter LinkedIn Pinterest Tumblr Share on Facebook Share on Twitter Screwworm fly detected in Texas decades after cattle threat was largely eradicated in U.S. Nation Jun 4, 2026 2:50 PM EDT The New World screwworm fly has reached south Texas, the U.S. Department of Agriculture confirmed Wednesday, the first time in decades that the parasite with flesh-eating larvae has threatened the nation's cattle industry and only the third time it's appeared in the U.S. in that time. READ MORE: What to know about flesh-eating screwworms (and why you don't need to panic) Agriculture Secretary Brooke Rollins said the case was in a 3-week-old calf in La Pryor, Texas, about 50 miles (80 kilometers) from the Mexico border. Texas State Veterinarian Bud Dinges said he has established a 12-mile (20-kilometer) quarantine zone, prohibiting the movement of any warm-blooded animal — including pets — outside that zone without an inspection. Rollins said there have been no other detections of the fly in the U.S., and officials were quick to say that while the fly's larvae are a threat to livestock production, they don't infest food. Properly treated, even the infested calf should recover, Rollins said. Educate your inbox Subscribe to Here’s the Deal, our politics newsletter for analysis you won’t find anywhere else. Rollins, U.S. and Texas agriculture officials, and cattle industry leaders have been sounding public alarms about the fly's movement across Mexico for more than a year, spurred on by memories of it causing tens of millions of dollars of losses — potentially billions in today's dollars — before its eradication in the 1970s. It is the first case confirmed in Texas since 1966, Rollins said. Paul Janda, a cattle rancher from Schulenburg, Texas, examines documents covering economics and the threat of the New World Screwworm parasite during the Fayette County Cow/Calf Clinic and Trade Show in La Grange, Texas, on May 1, 2026. Photo by Joel Angel Juarez/ Reuters The months of effort to keep the fly out of the U.S. have included dropping millions of sterile screwworm flies in the area to mate with wild females — the same method used successfully before the fly was eradicated. Rollins said the USDA is confident enough in its preparations that it believes "there is no threat of mass infestation." "There is no reason to believe this incursion will result in establishment of the pest in our country," Rollins said. READ MORE: 7 reasons flesh-eating screwworms are as gross as you think The announcement of the suspected case comes only a day after Rollins had an online news conference to highlight the nearness of the threat, with cases been confirmed in Mexico as close as 25 miles (40 km) from the border — and to outline the USDA's efforts