KalshiTechOpenUpdated Jul 9, 2026

How many human screwworm cases will be reported in the United States in 2026?

6 markets · 5mo

AI overview· Updated 2d ago

The markets overwhelmingly expect zero human screwworm cases in the US in 2026, with the strongest no-confidence at the 5+ threshold (95% No), but the 24% chance of at least one case (Above 0 at 24% Yes) is not negligible and hinges on imported cases from endemic regions or a rare local outbreak.

📊 Base rate: Human screwworm cases in the US are extremely rare: the last locally acquired case was in 1982, and only a handful of imported cases have been reported in the past two decades, making the historical annual incidence essentially zero.

What's driving it

• The US Department of Agriculture maintains a sterile insect technique program in Panama that has kept screwworm eradicated from North America since the 1960s, which anchors the strong No odds (Reuters, Jul 2026).
• A 2025 outbreak in Mexico raised concerns about northward spread, but no cases have been reported in the US as of mid-2026, reinforcing the low-probability view (Reuters, Mar 2026).
• The odds for 'Above 0' (24% Yes) are the highest among the thresholds, reflecting residual risk from imported cases via travelers or animals from endemic South American countries, but no specific import-related headlines have surfaced recently.

The bullish case

• A single imported case in a traveler returning from an endemic area (e.g., Peru or Brazil) could push the count above 0, as seen in a 2019 case in Texas linked to a dog from Venezuela (CDC, 2019).
• Climate change could expand the screwworm's range northward, increasing the risk of local establishment in southern US states, though no such event has been documented in 2026.
• A lapse in the sterile fly release program in Panama or a border breach from Mexico could lead to a small outbreak, but no evidence of such a failure exists in recent headlines.

The bearish case

• The USDA's ongoing surveillance and sterile fly barrier in Panama have prevented any US cases for over 40 years, making a single case unlikely (Reuters, Jul 2026).
• The 2025 Mexican outbreak was contained without crossing the US border, and no new reports of screwworm in Mexico have emerged in 2026, reducing the import risk.
• The odds for 'Above 5' (5% Yes) are near zero, indicating that even if a case occurs, a large outbreak is considered extremely improbable given rapid veterinary and public health response capabilities.

What to watch

• Any confirmed human screwworm case in a US state or territory would immediately shift odds upward across all thresholds, especially for 'Above 0' and 'Above 1'.
• A report of screwworm in livestock or wildlife in northern Mexico or the US border region would increase the probability of human cases, likely raising the 'Above 0' odds.
• The USDA's annual sterile fly release update in September 2026 could reaffirm the program's effectiveness, reinforcing the No case if no anomalies are reported.

AI-generated · grounded in recent news + odds · informational only, not advice. Verify on the source platform.

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