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Screwworm Returns to US After Decades of Eradication

  //food-wine.news-articles.net/content/2026/02/13 .. -returns-to-us-after-decades-of-eradication.html
  Published in Food and Wine on Friday, February 13th 2026 at 2:16 GMT by Newsweek
      Locales: Florida, Texas, Arizona, North Carolina, UNITED STATES

Tallahassee, Florida - February 13th, 2026 - After decades of successful eradication, the New World screwworm (Cochliomyia hominivorax) has resurfaced in the United States, with confirmed cases now appearing in multiple Florida counties. The parasitic fly, a devastating threat to livestock, wildlife, and potentially even humans, is prompting a swift response from agricultural and health officials, raising concerns about a potential widespread outbreak and the challenges of re-establishing control.

Understanding the Enemy: The Screwworm Life Cycle

The New World screwworm is native to Central and South America, and its lifecycle is particularly insidious. The female fly deposits her eggs directly into open wounds of warm-blooded animals - cattle, horses, pets, deer, and other wildlife are all vulnerable. Once hatched, the larvae, commonly known as maggots, feed voraciously on the living tissue of the host, causing excruciatingly painful, slow-healing wounds. These wounds are prone to secondary infections, leading to severe illness, reduced productivity in livestock, and even death if left untreated. The economic impact on ranchers and farmers can be substantial, encompassing veterinary bills, lost production, and diminished animal value.

A Triumph of Science: The Eradication Story - and Why it Failed to Last

Between the 1950s and 1970s, the United States, in collaboration with Mexico and Central American nations, achieved a remarkable victory: the eradication of the screwworm from the continental U.S. This success was largely due to the innovative application of the Sterile Insect Technique (SIT). Millions of male screwworms were sterilized through gamma irradiation and then released into the wild. When these sterilized males mated with wild females, no viable eggs were produced, effectively breaking the reproductive cycle and drastically reducing the population. This program was hailed as a model for invasive species control and a testament to the power of scientific collaboration.

However, despite these gains, eradication efforts in Mexico faced consistent challenges due to logistical difficulties, funding shortages, and political instability. The screwworm persisted across the border, acting as a constant source of re-infestation risk. In recent years, the continued presence of screwworm in parts of Mexico and the Caribbean, coupled with several contributing factors, has created the perfect storm for its return to U.S. soil.

What's Driving the Resurgence? A Complex Web of Factors

Experts believe the current outbreak is a result of a confluence of factors. Increased global trade and travel play a significant role; the unintentional transportation of infected animals or larvae via cargo ships, planes, or even personal vehicles is a plausible vector. The relaxation of certain biosecurity protocols in recent years, driven by economic pressures to streamline trade, may have inadvertently lowered the barrier to entry for the screwworm. Climate change, with its associated shifts in weather patterns and increased migration of animals, could also be contributing to the spread.

Furthermore, the rise in illegal animal transport, bypassing official inspection points, presents a significant challenge to biosecurity efforts. Experts point to a growing black market in livestock and exotic animals, increasing the risk of undetected screwworm introduction. Finally, decreased funding for border inspection and animal health surveillance programs over the last decade has hampered early detection and rapid response capabilities.

Florida on the Front Lines: The Current Response

The Florida Department of Agriculture and Consumer Services is leading the response, working closely with federal agencies, including the USDA's Animal and Plant Health Inspection Service (APHIS). Efforts are focused on enhanced surveillance, including increased trapping and testing of livestock and wildlife in affected areas. Ranchers and pet owners are being urged to report any suspicious wounds or infestations immediately. Veterinarians are being kept informed about the outbreak and provided with diagnostic resources. A public awareness campaign is underway to educate the public about the screwworm, its risks, and preventative measures.

Critically, officials are actively considering a large-scale re-implementation of the Sterile Insect Technique. However, scaling up production of sterile flies and deploying them effectively across affected areas will require significant investment and logistical planning. The USDA is currently evaluating the feasibility of establishing a dedicated facility for screwworm mass-rearing and sterilization.

The Stakes Are High: Protecting Agriculture, Wildlife, and Public Health

The return of the screwworm is more than just an agricultural issue. A widespread outbreak could have devastating consequences for Florida's multi-billion dollar livestock industry. Beyond economic losses, the ethical implications of animal suffering are significant. The health of wildlife populations, including endangered species, is also at risk. While human infections are rare, they can occur, causing myiasis - a painful and potentially serious condition. A robust and coordinated response is crucial to prevent the screwworm from gaining a foothold and jeopardizing the well-being of both animals and people.