Every deadline that applies

The only truly irreversible one. A stool culture can be taken while someone is symptomatic and not afterwards. If nobody identifies the organism, most claims end there regardless of how much time remains to file.

If the exposure involved a public school, a municipal water system, a public pool or splash pad, a county fair run by a public body, or a public hospital, claims against government entities generally require a formal notice of claim within a short administrative window before any lawsuit is possible.

Miss it and the claim is typically barred permanently, even though the ordinary statute of limitations hasn't run. It is the most common way a strong case is lost on procedure.

Your state's personal injury statute of limitations governs, most commonly two years, some states one or three. Wrongful death is frequently shorter and runs from the date of death.

Product liability claims may run on a different clock, and some states apply a discovery rule where the connection genuinely wasn't knowable earlier — relevant where an outbreak is declared long after the illness.

Deadlines for minors are typically tolled, which matters because most HUS patients are children. That is a reason not to panic, not a reason to wait.

Waiting for a CDC investigation to close, waiting for a recall, negotiating with an insurer, or corresponding with a company's customer service. None of these toll a statute of limitations, and nobody involved is obliged to warn you it's approaching.