Screwworm outbreak in U.S. animals prompts call for vigilance
Hunters are urged to report sightings of the flesh-eating parasite as it resurfaces in livestock and wildlife across the nation.
Millions of hunters will be in fields and wooded areas, where they can help spot and report any signs of screwworm. Michigan Department of Natural Resources (Photo via The Conversation)
More than 100 cases of New World screwworm have been confirmed in animals across the United States throughout 2026. The parasitic fly, which feeds on the living flesh of warm-blooded hosts, has been identified in a variety of species including elk, cattle, horses, dogs, sheep, and goats.
The parasite was largely eradicated from the country during the 1960s and 1970s. However, the current outbreak began to emerge following the pest's northward movement through Mexico and Central America. Initial cases in the U.S. were detected in Texas in June 2026, marking the first time the state has seen the parasite in decades.
The U.S. Department of Agriculture is currently monitoring the situation as the infestation continues to impact livestock and wildlife. Previous reports from this year have indicated that the presence of the parasite has disrupted cattle supply chains and led to requests for increased federal resources, including more veterinary staffing and research into sterile fly production.
The nation’s 11.5 million hunters are being identified as a potential first line of defense in containing the spread. By monitoring for signs of the parasite in the field and reporting findings, hunters may assist federal agencies in tracking and managing the outbreak as it persists into the end of the year.