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Prediction market on metaculus. New World screwworm ([Cochliomyia hominivorax](https://en.wikipedia.org/wiki/Cochliomyia_hominivorax)) is a parasitic fly native to the tropical and subtropical regions of the Americas. Unlike most flies, its larvae feed on the living tissue of warm-blooded animals, a condition known as [myiasis](https://en.wikipedia.org/wiki/Myiasis). The species [was eradicated](https://www.nal.usda.gov/exhibits/speccoll/exhibits/show/stop-screwworms--selections-fr/introduction) from the United States through a biological control program in the mid-twentieth century, which relied on the mass release of sterile male flies to suppress reproduction anad successfully eliminated the pest from North America by 1966. The screwworm [remains endemic](https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm) in parts of South America and the Caribbean, and sporadic detections in the US have historically been linked to infested animals imported from affected regions. Resurgence concerns have raised [after 2023](https://agr.wa.gov/departments/animals-livestock-and-pets/animal-health/animal-diseases/new-world-screwworm), with the screwworm spreading northward through every country in Central America and into Mexico, breaching the biological barrier that had historically confined it to South America. By January 2026, screwworm had been confirmed in the Mexican state of Tamaulipas, approximately 200 miles from the U.S. border. As of late February 2026, the outbreak region [had reported](https://www.cdc.gov/new-world-screwworm/situation-summary/index.html) more than 156,000 animal cases and over 1,350 human cases, and the USDA had shifted sterile fly dispersal operations northward to defend the border. One travel-associated human case [has been confirmed](https://www.avma.org/news/first-human-screwworm-case-us-reported) in a person who returned to the United States from the affected region, though no locally acquired infestation has been detected on U.S. soil.
Resolves: 1/1/2027.