Federal health officials declared the largest recorded U.S. cyclospora outbreak over after nearly 13,000 reported illnesses. The multistate outbreak was associated with recalled iceberg lettuce. The affected lettuce was no longer available for sale when officials closed the investigation. Produce outbreaks can be difficult to trace because products move through farms, processors, distributors and retailers before illnesses are recognized.
Investigators did not determine where or how the produce became contaminated. Cyclospora is a microscopic parasite that can cause prolonged gastrointestinal illness. Cyclospora infections may be diagnosed after a delay, complicating interviews about food consumed days or weeks earlier. Declaring an outbreak over means new linked illnesses are no longer appearing at the level that sustained the investigation.
The parasite spreads when food or water is contaminated with human feces containing the organism. Illness reports reached nearly 13,000, making the event the largest recorded U.S. outbreak involving the parasite. A closed outbreak can still leave food-safety agencies with follow-up work on growing and handling practices.
Cases were reported across multiple states rather than being confined to a single restaurant or community. A recall removed implicated product while epidemiological and supply-chain work continued. Exact case totals may change as delayed reports are reconciled. Officials did not identify the original contamination site or mechanism, so the causal chain remains incomplete.
The absence of a confirmed origin limits the precision of prevention work. A lettuce association can guide recalls and consumer warnings, but investigators still need records that connect a field, water source, harvesting crew, processor or distribution point to contamination. Without that link, the closure of the case documents the end of observed spread rather than a complete explanation of how it began.
What to watch: Any follow-up report identifying a farm, processor or water source. Changes to lettuce surveillance, testing or traceback requirements.