Screwworm Eradication: The Invisible Threat to US Livestock is Back
- The New World screwworm, a flesh-eating maggot that burrows into living tissue, has been detected in the Florida Keys for the first time since the 1960s, prompting an emergency USDA quarantine zone and mandatory livestock inspections.
- Unlike standard fly larvae, screwworm maggots feed on the healthy flesh of live mammals, causing agonizing, septic wounds that are often fatal if left untreated, making it a top biosecurity threat.
- The eradication strategy relies on sterile insect technique (SIT)—mass-releasing millions of sterilized male flies to outcompete wild males—a method that successfully eliminated the pest from the entire US in 1966.
- A single undetected infected animal can trigger a multi-state outbreak, because screwworm flies can fly up to 200 miles and lay up to 3,000 eggs in a lifetime, putting cattle, sheep, pets, and even deer at risk.
- The crisis is exacerbated by climate change; warmer winters allow screwworm populations to survive in regions previously too cold, meaning this is not just a Florida issue but a potential national agriculture emergency.