How the US was left exposed to the flesh-eating screwworm, years into the outbreak

In November 2024, Mexico and Panama collectively produced roughly 150 million sterile flies weekly, a figure far below the 500 million per week required to keep the screwworm in check, as experts pointed out. The United States lacks its own sterile-fly production facility and will not have one operational until spring 2027. The screwworm, notorious for devouring living tissue and proving fatal to untreated animals, has infiltrated most of Mexico, causing around 51,000 confirmed cases.

The United States has reported 120 cases thus far. In February 2023, Panama's Darien province faced approximately 800 screwworm cases, a crucial barrier to the pest's containment. Despite increasing sterile-fly production, challenges such as political transitions, funding delays, bureaucratic obstacles, and strained US-Mexico relations have impeded efforts to bolster fly supplies.