Based on official confirmation (CDC, hospital where the case occurred).
UPDATE 2026-07-12: Only new polio cases acquired after market creation count. If that was not clear previously, let me know and I will reimburse your trading losses based on the vague description.
1,000Does post-polio syndrome count? Martha Lillard - Wikipedia
@Yfo This is an edge case I missed when creating the question. It was intended (but not written) to only include cases of polio acquired after question creation, to model the situation when antivax movements and reductions in foreign aid (or anything else) lead to resurgence of polio.
If you or anyone else lost mana trading on the idea that old infections count towards resolution, I am happy to reimburse you by a managram (just let me know here what the amount is).
I would also say this specific case is not very clear as it is definitely not solely attributable to polio.