Federal health officials have closed the largest Cyclospora outbreak ever recorded in the United States, with a final count of 12,883 illnesses across 21 states, at least 570 hospitalizations, and two deaths, both in Michigan.
The CDC declared the outbreak over on Sept. 11, about three and a half weeks after the last reported illness onset on Aug. 17. The CDC's final investigation update tied the illnesses to iceberg lettuce sourced from central Mexico and recalled by Taylor Farms de Mexico, and added one more state, Virginia, to the tally before closing. Illnesses linked to the outbreak began on June 14.
For households, the closure answers the question many shoppers were asking through the summer: bagged and shredded iceberg lettuce is no longer under an active outbreak warning. But the story is not finished. The Food and Drug Administration says its own investigation into the supplier remains open, along with inquiries into other Cyclospora clusters that surfaced this summer, meaning the root cause of the contamination has not been established publicly.
The Final Count Rose After the Recall Ended
Federal officials announced the investigation on July 16. A day later, traceback converged on a single supplier, and Taylor Farms de Mexico began a voluntary recall covering Marketside-brand iceberg salad and shredded lettuce sold at Walmart, with best-if-used-by dates running from July 18 to Aug. 3, along with a longer list of food service products distributed to restaurant chains.
Case counts kept rising for weeks afterward, which unsettled shoppers who assumed a recall meant an immediate end to illness. The explanation is timing. Cyclospora can take roughly a week or more to produce symptoms, and laboratory confirmation and interviews add further delay, so a newly reported case is often an older infection finally counted. Most illnesses in this outbreak began before the recall was announced.
The FDA's outbreak investigation page noted that best-by dates on the recalled lettuce had passed and that the product should no longer be available in stores or restaurants. The CDC cautioned in its closing update that "the true number of sick people in this multistate outbreak was likely higher" than the confirmed figure, because many people with diarrheal illness never get tested. At the peak of the outbreak, before the recall, more than 1,000 infections occurred in a single day, Food Safety News reported.
Michigan Absorbed the Heaviest Share of Illness
No state was hit harder than Michigan, where both deaths occurred. The Michigan Department of Health and Human Services has tracked its own statewide cyclosporiasis count through the outbreak investigation period, reporting 14,718 cases and 366 hospitalizations as of Sept. 3. The state typically identifies about 50 cases in an entire year.
Michigan's number is larger than the national outbreak-linked total because the state counts all cyclosporiasis cases reported during the investigation window, not only those investigators confirmed as linked to the recalled lettuce. Both Michigan deaths involved people with significant underlying health conditions that may have been affected by cyclosporiasis and dehydration, according to the state.
Southeast Michigan carried the earliest burden. The state identified its first case on June 22, and the Monroe County Health Department announced on June 29 that it was investigating a cluster, days before the state issued a statewide outbreak announcement and weeks before the national link to lettuce was established. Early cases concentrated in Monroe, Lenawee and Washtenaw counties. Over the full outbreak, the largest county totals shifted to Wayne, Oakland, Washtenaw and Ingham.
Produce Safety Questions Reach Beyond One Grower
The closure does not end the federal work. The FDA's post-outbreak response page says the agency is continuing its investigation of Taylor Farms de Mexico while shifting toward prevention-oriented activity, and that it is still examining other Cyclospora clusters from this summer. The FDA began on-site inspections and sample collection at lettuce growers in Mexico on Aug. 20, and senior FDA and Mexican officials met during the week of Sept. 8 on a prevention framework for produce grown in Mexico. Across the May-to-September investigation period, the CDC reported 19,595 laboratory-confirmed cyclosporiasis cases acquired in the United States, a figure that includes the lettuce-linked outbreak and separate clusters.
That distinction matters for shoppers. It means contamination this summer was not confined to one product line from one facility, and the pathway by which the parasite reached the food supply has not been publicly resolved.
Cyclospora spreads when food or water is contaminated with feces containing the parasite. It does not pass directly from person to person. Symptoms include watery diarrhea, frequent bowel movements, loss of appetite, weight loss, stomach cramps and fatigue, and can last from a few days to more than a month, sometimes returning after an apparent recovery. Infection is treated with prescription antibiotics, so anyone with prolonged diarrheal illness should ask a clinician about testing rather than waiting it out.
Washing produce does not reliably remove the parasite, which is why outbreaks are addressed at the growing and processing level rather than the kitchen sink. Households that want to reduce risk can cook produce when practical, watch recall notices for items they buy regularly, and keep receipts for fresh produce, which help in both recall checks and any illness investigation.
Several questions remain open. The source of contamination at the growing or processing stage has not been publicly identified, and the FDA has not said when its findings will be released. MedicalDaily will follow the agency's post-response updates.
Key Questions Answered
Is the outbreak really over? The CDC declared the multistate outbreak over on Sept. 11 after new illnesses stopped appearing and recalled product passed its best-by dates. The FDA's investigation into the supplier is still open.
How many people got sick? The final count was 12,883 illnesses in 21 states, with at least 570 hospitalizations and two deaths in Michigan. The CDC said the real total was likely higher because many cases go untested.
What product was recalled? Iceberg lettuce sourced from central Mexico and processed by Taylor Farms de Mexico, including Marketside iceberg salad and shredded lettuce sold at Walmart, plus food service products sent to restaurant chains.
Is lettuce safe to buy now? The recalled product is past its best-by dates and should no longer be in stores or restaurants, and there is no active outbreak warning tied to it. Ordinary produce-handling practices apply.
What are the symptoms of cyclosporiasis? Watery diarrhea, frequent bowel movements, cramping, appetite and weight loss, and fatigue. Symptoms can last weeks and may seem to improve before returning.
Can washing lettuce prevent infection? Washing does not reliably remove the parasite. Prevention depends on controls at the farm and processing level, which is why federal investigators focus there.
What should someone do if they are still sick? Contact a clinician and ask specifically about Cyclospora testing, since standard stool panels do not always include it. The infection is treated with prescription antibiotics.
