A stomach parasite spread by feces on fresh produce has now sickened people in 41 states, federal health officials said - five days after the FDA pulled back the only lab test linking the outbreak to the lettuce it recalled.
The Centers for Disease Control and Prevention said July 21 it has confirmed 4,173 domestic cases of cyclosporiasis since May 1 and is tracking more than 7,400 additional reported cases that labs have not yet confirmed. Many of those came from Michigan and Ohio. The agency has moved to weekly surveillance updates this year because of the increase over the same period in 2025.
The confirmed total is nearly four times the 1,180 cases the agency recorded during all of last season.
Forty-one states have reported cases, up from 34 four days earlier. Alabama, Idaho, Mississippi, Missouri, Nevada, New Hampshire, North Dakota and Wyoming reported their first cases of the summer this week.
Those cases are not all one outbreak. The CDC says it is investigating multiple separate clusters this summer. The lettuce investigation is one of them, and it covers five states.
Of the confirmed patients nationally, 308 have been hospitalized and none have died. They ranged in age from 2 to 95. Fifty-six percent were female, and the median date of illness onset was June 26.
Taylor Farms, a California-based supplier, recalled iceberg lettuce sourced from central Mexico on July 17 after investigators tied it to illnesses in Indiana, Kentucky, Michigan, Ohio and West Virginia. The lettuce was served at some Taco Bell locations. That cluster accounts for 1,644 reported illnesses and 94 hospitalizations.
Two days after the recall, the FDA said a lettuce sample it had announced as testing positive for the parasite had not actually tested positive.
"During a quality check by our laboratory personnel, we did detect the false positive, and we did issue a correction," Donald Prater, the agency's acting deputy commissioner for food, told reporters on a call.
Prater said the recall stands.
"It's important to note that the re-evaluation of the sample does not alter the data supporting the outbreak advisory that prompted the current voluntary recall," he said. "FDA's traceback investigation and the outbreak data continue to converge on shredded iceberg lettuce from Taylor Farms location in central Mexico."
The case against the lettuce now rests on shipping records and patient interviews. The CDC says 90 percent of the patients it interviewed in the five-state cluster reported eating iceberg lettuce. No sample of the recalled product has tested positive for the parasite.
That last point is less damning than it sounds. Cyclospora is among the hardest foodborne pathogens to catch in a sample. It cannot be grown in a laboratory - the parasite needs a human host to reproduce - so investigators cannot culture a suspected find to confirm it. It occurs in very small numbers, meaning samples must be enormous to detect anything. Its oocysts lodge in surface crevices that resist washing. Positive product samples are rare in Cyclospora investigations even when the source is eventually established.
Taylor Farms said July 20 that no Taylor Farms-branded products are involved in the recall, that it will not source iceberg lettuce from central Mexico "for the remainder of the growing season," and that it is working with health officials.
State health departments are reporting far higher numbers than the CDC. Michigan counted 6,571 cases and 102 hospitalizations as of Monday. The Toledo-Lucas County Health Department in Ohio counted 2,149. The CDC does not include probable cases in its updates; many states do.
The federal count is also climbing on both sides of the ledger. A week ago the agency listed 1,645 confirmed cases and more than 5,100 awaiting analysis. The confirmed number rose by about 2,500. The unconfirmed number rose by about 2,300.
Cyclosporiasis symptoms include watery diarrhea, cramping, loss of appetite and fatigue. Symptoms typically begin about a week after exposure. The illness is treated with antibiotics.
Cases appear every summer. The CDC's season runs through August 31.
Federal investigators have pulled a product off the shelves that no laboratory test has implicated, on the strength of shipping records and what sick people remember eating. With this parasite that may be the only call available. It also means that when the season closes on August 31, the case against the lettuce will rest roughly where it rests today - and the thousands of cases outside those five states will still be looking for a source.
A shitty situation all around...