The CDC is now reporting two numbers side by side for this summer's Cyclospora outbreak, and the second one is the more revealing of the pair. The agency has laboratory-confirmed 6,707 domestically acquired cases since May 1, and says it is aware of more than 11,500 additional illnesses that are, in its words, "not laboratory confirmed or require further investigation and analysis."
In other words, the confirmed count represents roughly a third of the illnesses officials know about. That ratio, more than any single total, is the honest description of where this outbreak stands.
The CDC also says the multistate outbreak linked to iceberg lettuce now spans nine states, up from the five named earlier this month. That expansion is the development most likely to matter to a household outside the Midwest.
Why the Confirmed Count Lags So Far Behind
The gap is not a failure of arithmetic. It reflects how cyclosporiasis is diagnosed and counted.
Cyclospora is a parasite that standard stool testing routinely misses. A clinician has to specifically order testing for it, and the Michigan health department's provider bulletin has warned physicians not to rely on a general ova and parasite order. If no one orders the right test, the case never becomes laboratory-confirmed.
Confirming a domestically acquired case also requires ruling out travel. Cyclosporiasis is common in parts of the world with different water and produce safety conditions, so investigators must establish that a patient did not travel abroad in the two weeks before getting sick. That takes an interview, and interviews take time.
The CDC has said it can take as long as six weeks to determine whether a sick person belongs to a given Cyclospora outbreak. Many people also recover without seeking care at all and are never tested. The agency notes explicitly that states report different totals on their own websites because states also count probable illnesses, while the CDC and FDA report only laboratory-confirmed cases.
The trajectory of the gap tells its own story. When the CDC issued its health advisory on July 14, it had confirmed 1,645 domestic cases with roughly 5,100 awaiting further analysis. Confirmed cases have since quadrupled, and the pool of unconfirmed illnesses has more than doubled.
Where the Cases Are Concentrated
Michigan remains the epicenter by a wide margin. The state health department has reported at least 10,077 cases since May 1, a figure CNN reported from MDHHS as of July 29. Michigan typically records around 50 cases in an entire year.
Those two figures deserve to sit next to each other, because the scale of the departure from normal is the clearest measure of how unusual this summer is.
MDHHS's separate outbreak-period dashboard, which counts from June 22, listed 9,680 cases as of July 28, up from 9,253 the day before. The department cautioned that roughly 475 of the cases added on July 27 were delayed laboratory reports rather than a single-day surge, a distinction worth preserving. As of July 23, 160 patients had told the department they were hospitalized.
Cases have appeared in 70 of Michigan's 82 counties. The heaviest concentrations reported by the Detroit News from state data were Wayne County with 1,036 cases, Washtenaw with 773, Oakland with 710, and Ingham with 698. That distribution tracks population density in the Detroit, Ann Arbor, and Lansing metro areas.
Across the eight other states tied to the outbreak, more than 5,000 additional cases have been reported as of July 29: Ohio with at least 2,574, Indiana with 1,092, Illinois with 532, Kentucky with 468, Kansas with 461, Oklahoma with 303, West Virginia with 245, and Pennsylvania with 82.
MDHHS has said it cannot state with certainty that every illness traces to the same exposure, but that the concentrated, sharp increase "the vast majority of these illnesses are associated with the same outbreak."
What Is Confirmed, What Is Alleged, and What Is Not Settled
Confirmed: epidemiologic and traceback data implicate shredded iceberg lettuce from a single Mexican supplier, Taylor Farms de Mexico, served at some Taco Bell locations. Michigan investigators found that 90% of 190 interviewed patients who had eaten at Taco Bell reported eating iceberg lettuce. On July 17, the supplier moved to remove all iceberg lettuce sourced from central Mexico from the U.S. market, including Marketside-brand products sold at Walmart with best-by dates through August 3.
Also confirmed: the federal nine-state subset of the outbreak involves 1,947 people reporting Taco Bell exposure, with 98 hospitalizations and no deaths, across Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, Oklahoma, Pennsylvania, and West Virginia.
Under investigation: whether the contaminated lettuce reached other restaurant chains or retailers. The CDC has also said it is investigating other Cyclospora clusters nationally that are unrelated to this outbreak.
Not settled: the source of Michigan's broader statewide outbreak. MDHHS has said lettuce and salad greens are a possible source but has not identified a single product, grower, or supplier, and has not ruled out other foods.
Sources also disagree on scope in one respect worth flagging. The CDC's surveillance page describes the lettuce-linked outbreak as affecting nine states, while its outbreak investigation page was last updated July 16 and still describes five. The nine-state figure is the newer of the two.
Alleged only: lawsuits have been filed against Taco Bell and Taylor Farms by affected Michigan residents. Those are allegations, and no defendant has been found liable.
One point of caution about early reporting. The FDA has said a border screening sample that initially tested positive was later determined to be a false positive, and that this did not change the basis for its investigation or the voluntary recall.
What Households Should Do Now
The recommendation from the CDC is specific rather than general: do not eat shredded iceberg lettuce from Taylor Farms de Mexico served at Taco Bell locations in the nine affected states, and check refrigerators for recalled Marketside iceberg and shredded lettuce products with best-by dates through August 3.
MDHHS has advised buying whole heads of lettuce rather than pre-washed bagged greens or pre-mixed salad kits during the investigation. Washing does not reliably remove Cyclospora. Heating food to 158 degrees Fahrenheit does kill it.
Symptoms usually begin about a week after exposure, though the range runs from two days to more than two weeks. They include watery and sometimes explosive diarrhea, stomach cramps, nausea, loss of appetite, and fatigue. Untreated, illness can last more than a month and can relapse.
Anyone with sudden and ongoing diarrhea should contact a clinician and specifically mention possible Cyclospora exposure, because the test has to be ordered by name. Cyclosporiasis is treated with a specific antibiotic combination, and treatment shortens illness substantially. Urgent care is warranted for signs of severe dehydration, bloody stool, high fever, or inability to keep fluids down.
People with weakened immune systems, including those in cancer treatment, transplant recipients, people with HIV, pregnant patients, and older adults, are most likely to experience prolonged or severe illness. Cyclospora does not spread person to person, so household members do not need to isolate from one another.
What Happens Next
The Cyclospora season the CDC recognizes runs through August 31, and the agency expects case counts to keep rising until then. MDHHS updates its case counts on a rolling basis, with cases by date reported refreshed weekly on Thursdays. The FDA is continuing traceback work and has increased border screening on implicated products.
The most important open questions are whether the lettuce reached distribution channels beyond the nine identified states, what is driving Michigan's broader outbreak, and how many of the 11,500 unconfirmed illnesses will ultimately be confirmed. MedicalDaily will monitor CDC surveillance updates and state dashboards.
The bottom line: the CDC has confirmed 6,707 Cyclospora cases and knows of more than 11,500 more it has not yet confirmed. Households in the nine outbreak states, and anyone who bought recalled lettuce, are most affected. The reasonable action is to discard recalled product, buy whole heads of lettuce for now, and ask a clinician for Cyclospora testing by name if diarrhea persists. The central uncertainty is the true size of the outbreak.
Developing Story Timeline
July 29 to 30, 2026: CDC surveillance reports 6,707 laboratory-confirmed domestic cases since May 1, and more than 11,500 additional illnesses not yet confirmed, and describes the lettuce-linked outbreak as spanning nine states.
July 28, 2026: MDHHS reports 9,680 cases in its outbreak-period count, noting about 475 cases added the previous day were delayed laboratory reports.
July 17, 2026: Taylor Farms de Mexico moves to remove all iceberg lettuce sourced from central Mexico from the U.S. market.
July 16, 2026: CDC reports 1,644 cases with Taco Bell exposure across five states and 94 hospitalizations.
July 14, 2026: CDC issues a health advisory on domestically acquired cyclosporiasis, with 1,645 confirmed cases and roughly 5,100 awaiting analysis.
July 1, 2026: MDHHS announces an outbreak of cyclosporiasis occurring in Michigan.
Frequently Asked Questions
Why are there two different case numbers? The CDC reports only laboratory-confirmed domestically acquired cases, currently 6,707. It separately tracks more than 11,500 illnesses that are not yet confirmed or need further investigation, many reported by Michigan and Ohio.
Which states are in the lettuce-linked outbreak? Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, Oklahoma, Pennsylvania, and West Virginia.
What food should I avoid? Shredded iceberg lettuce from Taylor Farms de Mexico served at Taco Bell locations in those states, and recalled Marketside iceberg and shredded lettuce sold at Walmart with best-by dates through August 3, 2026.
Will washing lettuce protect me? No. Washing does not reliably remove Cyclospora. Heating food to 158 degrees Fahrenheit kills the parasite.
What are the symptoms and when do they start? Watery, sometimes explosive diarrhea, cramps, nausea, appetite loss, and fatigue, usually beginning about a week after exposure, with a range of two days to more than two weeks.
How is it diagnosed and treated? Through a stool test that must specifically target Cyclospora, since standard parasite panels often miss it. It is treated with antibiotics plus rest and fluids, and treatment substantially shortens illness.
Can I catch it from a family member? No. Cyclospora is not known to spread person to person.
When should someone seek urgent care? For signs of severe dehydration, bloody stool, high fever, or inability to keep fluids down.
