Screwworm Fly Detected in Texas for First Time Since 1966

The New World screwworm fly, a highly destructive parasitic insect known for its flesh-eating larvae, has been confirmed in LaPryor, Texas, marking its first appearance in the state since 1966 and only the third detection in the United States in decades. Agriculture Secretary Brooke Rollins announced Wednesday that the case involves a three-week-old calf located approximately 50 miles from the Mexican border. In response, Texas State Veterinarian Bud Dinges has established a 12-mile quarantine zone prohibiting the movement of any warm-blooded animals, including household pets, without prior inspection. The U.S. Department of Agriculture has emphasized that while the larvae pose a significant threat to livestock, they do not infest food and the affected calf is expected to recover with proper treatment. Officials have detected no other cases of the fly elsewhere in the United States. The parasite, which was historically eradicated from the U.S. cattle industry by the 1960s and 1970s, caused tens of millions of dollars in losses during the 1970s, amounts that would translate to billions today. The female flies lay eggs in open wounds or mucous membranes of warm-blooded animals, and the hatching larvae consume living flesh, a characteristic that distinguishes them from most other fly species. Infestations can affect livestock, wild mammals, pets, and humans, potentially leading to death if left untreated. To combat the threat, the USDA is employing the sterile insect technique, dropping millions of sterile screwworm flies in the area to mate with wild females. Since female flies mate only once in their lives, mating with a sterile male prevents eggs from hatching, gradually declining the population. The agency has allocated $21 million to convert a fruit-fly breeding facility in southern Mexico into a screwworm fly breeding operation expected to be operational next month, opened a new dispersal center in southern Texas, and begun construction on a $750 million screwworm factory. Additional measures include deploying 8,000 fly traps along the U.S.-Mexico border and closing the border to livestock imports from Mexico. Secretary Rollins expressed confidence in these preparations, stating there is no threat of mass infestation and no reason to believe this incursion will result in establishment of the pest in the country.