What Is Cyclospora? The Parasite Behind the Iceberg Lettuce Recall

A parasite most people have never heard of has spent July attached to one of the most ordinary things in the fridge: iceberg lettuce. Health agencies are investigating a multistate outbreak of Cyclospora infections, a recall has pulled affected lettuce from the market, and the case count has climbed into the thousands. Here is what the parasite actually is, and what the agencies have reported so far.

The short versionA microscopic parasite, spread through food

Cyclospora cayetanensis is a single-celled parasite far too small to see. According to the CDC, it spreads when food or water comes into contact with human faeces — in practice, most often when fresh produce is irrigated or rinsed with contaminated water somewhere along the supply chain. It causes an intestinal infection called cyclosporiasis.

One quirk explains why outbreaks behave the way they do: the parasite is not infectious the moment it leaves the body. It needs days to weeks in the environment to mature before it can infect anyone. That means cyclospora is not passed directly from person to person the way a stomach bug is — it travels on food. It also means investigators are usually tracing a shipment, not a sick cook.

Where the investigation standsThe numbers, and the date on them

In its update of 3 September 2026, the CDC reported 11,458 illnesses across 20 states — a count that has grown sharply since July for a specific procedural reason: as state and local officials completed more interviews, the CDC widened the outbreak to include people who reported eating at Taco Bell or eating the recalled Taylor Farms de Mexico iceberg lettuce, many of whom fell ill before the 17 July recall. Six states — Arkansas, Iowa, Missouri, Nebraska, New Hampshire and North Carolina — were added in the 5 August update alone, and five more by September. At least 495 hospitalisations have been reported, and two deaths, both in Michigan. Illness onset dates run from 14 June through 15 August 2026, and the CDC says new cases are now declining.

Investigators pointed at the lettuce quickly, and for a plain reason: about 90 percent of the people interviewed reported eating iceberg lettuce. The FDA’s investigation initially centred on illnesses reported among people who had eaten at Taco Bell locations across five states — Indiana, Kentucky, Michigan, Ohio and West Virginia — which is how the traceback reached a shared lettuce supplier.

On 17 July 2026, Taylor Farms de Mexico voluntarily removed iceberg lettuce sourced from central Mexico from the US market. The FDA has said the recall stands, including after one product test came back as a false positive. It is worth being precise about what that chain does and does not establish: the epidemiologic and traceback work points to a contaminated lettuce lot moving through the supply chain, not to how any individual restaurant handled it. Cyclospora is a field-and-water contamination story, and it arrives already on the leaf.

Two caveats sit on every figure above, and the CDC states both plainly. The true number of people affected is almost certainly higher, because plenty of people recover without ever seeing a doctor or being tested. And there is a long lag: it can take as much as six weeks to determine whether a given illness belongs to an outbreak. A case count published today is a photograph of several weeks ago.

A note on the numbersTwo different counts are circulating

It is worth separating two figures that have been used interchangeably in coverage, because they measure different things. The outbreak count is the one above: illnesses investigators have linked to this specific lettuce, across 20 states. Circulating alongside it is the national seasonal total for cyclosporiasis — which the CDC notes includes other outbreaks and illnesses around the country that are unrelated to this lettuce entirely. This outbreak has grown large enough that, in the CDC’s own words, it “was a major driver to the increase of Cyclospora cases this year” — but the two numbers still are not the same number.

Cyclosporiasis is seasonal in the United States, clustering in late spring and summer, and a national tally always runs well ahead of any single outbreak within it. Both numbers are real. They are simply not the same number, and a headline that treats them as one overstates the size of this particular investigation.

The disputeTaylor Farms says it is not responsible

The company at the centre of the recall has now publicly rejected the finding. In a statement reported by Food Safety News, Taylor Farms said it has operated for more than 30 years and “produces billions of servings of safe, high-quality fresh produce annually,” that it has cooperated fully with regulators, and that it is “at the forefront of advances in food safety.” The company says it spends $200 million a year on food safety within a business turning over roughly $7 billion, and that its own testing found no parasite contamination.

Both positions are on the record, so both belong here. The CDC and FDA still describe iceberg lettuce from the company’s central Mexico facility as the most likely source of this outbreak. The company says it is not. Nothing in this article resolves that, and the investigation has not closed.

One point is worth understanding rather than taking sides on, because it explains why these disputes are so difficult to settle either way. A negative test on lettuce is weaker evidence than it sounds. Cyclospora takes a week or more to make someone ill and weeks longer to diagnose, and lettuce is perishable — so by the time investigators know which lot to examine, that lot has been eaten or binned. When the FDA did test wash water at this facility during an earlier outbreak, the sample came back inconclusive because the water was too cloudy for the laboratory method to work. Absence of a positive test is not the same as evidence of absence, and that cuts against certainty in both directions.

The part nobody disputesSeven years since the last inspection

Underneath the argument about this particular lot sits something neither side contests. CBS News reported that the FDA last inspected Taylor Farms de Mexico in 2019 — seven years before this outbreak. The visit before that was in 2013, and it happened because of a cyclospora outbreak as well.

That gap is not really about one company. Federal law directs the FDA to carry out roughly 19,200 foreign food safety inspections a year. In 2025 it conducted just under 1,000 — about five percent of the requirement, down 29 percent from 2024, and the lowest count since 2011 outside the pandemic years. The agency’s own internal estimate of a realistic target is 4,700, still nearly five times what it actually managed. In the decade the mandate has existed, CBS reported, the FDA has never reached even 10 percent of it.

An HHS official told CBS that measuring the agency this way misses the point: “Suggesting that FDA’s ability to protect the food supply can be measured by a single inspection statistic ignores the agency’s comprehensive oversight system, which prioritizes resources based on risk.” Taylor Farms, for its part, says it invests $200 million annually in food safety protocols and independent audits, “including regular monitoring of water quality and worker hygiene.”

The 2013 inspection is a matter of public record, and worth reading precisely rather than dramatically. Investigating an outbreak that sickened 631 people across 25 states, the FDA found the facility was washing salad components in recycled wash water, which it said could create “the potential for cross contamination,” and noted that some employee hand-washing facilities “do not appear to be of sanitary design.” It recommended the facility reassess its procedures. It did not conclusively identify a cause of that outbreak — which is precisely what the timing problem described above tends to produce, and the reason a thirteen-year-old document is being read closely again now.

What the infection looks likeMostly, a very long bout of diarrhoea

The CDC describes the hallmark symptom as watery diarrhoea, often with frequent, urgent bowel movements. Loss of appetite, weight loss, stomach cramps, bloating, increased gas, nausea and fatigue are all commonly reported alongside it. Some people report symptoms that seem to fade and then return.

What sets cyclosporiasis apart from a run-of-the-mill upset stomach is duration. This is not a twenty-four-hour thing. Untreated, it can run for weeks — which is exactly why it tends to get noticed, tested and counted. We have covered the symptom timeline in more detail separately.

Why lettuce, againThe produce that cannot be cooked

Leafy greens turn up in outbreak headlines with a regularity that starts to feel personal. It is not bad luck. Lettuce is grown close to the soil and to irrigation water, handled many times, mixed at scale so one contaminated lot can spread across a lot of bags, and — the decisive part — eaten raw. Heat is the step that neutralises most foodborne pathogens, and salad never gets it. We unpack why greens keep showing up in its own piece, along with what a rinse at the sink can and cannot do.

Where to follow itPrimary sources, not aggregators

Because this is an open investigation, the numbers in this article carry the date they were published and will age. The CDC is maintaining an outbreak page with the current case count and affected states, and the FDA is maintaining its own investigation page covering the product and recall side. Those two pages are the authoritative record. The summer has since produced a second multistate produce outbreak with the same supply-chain shape — we cover the jalapeño Salmonella recall at Chipotle and Qdoba separately. Anyone with questions about their own health is best served talking to a clinician rather than a website. This article is educational and is not medical advice.