Cyclospora Outbreak Count Tops 4000 as Second Cluster Emerges

Update July 23: The confirmed case count for the multistate outbreak linked to Taylor Farms de Mexico iceberg lettuce has climbed to 4173, more than double the 1644 cases reported on July 16. CDC is also tracking more than 7400 additional cases nationally that remain under investigation, and Michigan alone now reports 7171 cases through state surveillance data.^1-3

CDC and FDA have not changed the scope of the original 5-state cluster, which spans Indiana, Kentucky, Michigan, Ohio, and West Virginia, but the case count within it has nearly tripled in a week. Northwest Ohio has reported more than 2000 cases on its own, and hospitalizations tied to the outbreak remain proportionate to earlier reporting, with no deaths.^1,2

Michigan and Ohio cases climb as FDA opens new outbreak investigation

The jump reflects how quickly cyclosporiasis surveillance can catch up once state and federal case reporting align. CDC has said actual illness counts consistently lag confirmed tallies because of a six-week reporting delay between symptom onset and case notification, and many mild infections resolve without a clinician visit or Cyclospora-specific stool testing. FDA's traceback investigation continues to point to Taylor Farms de Mexico as the source of the shredded iceberg lettuce served at Taco Bell locations, and the recall issued July 17 remains in effect.

FDA has also opened a second, separate Cyclospora outbreak investigation, adding a cluster of 72 cases to its CORE Investigation table. That cluster has not been linked to a food source and is distinct from the Taylor Farms-associated outbreak, underscoring multiple concurrent Cyclospora clusters active this summer beyond the lettuce-linked cases.^1,2

FoodNet Cuts Draw Scrutiny as Case Counts Climb

Several US senators have written to Health and Human Services Secretary Robert F. Kennedy Jr, urging CDC to restore Cyclospora surveillance to the Foodborne Diseases Active Surveillance Network, or FoodNet, after the agency cut the parasite from that program in 2025. Public health researchers say the FoodNet cuts, while a legitimate surveillance concern, did not cause the current outbreak, since the multistate cluster was identified through the separate national notifiable-disease reporting system rather than FoodNet itself. CDC continues to recommend Cyclospora-specific stool testing for patients with prolonged or relapsing watery diarrhea.

Cyclospora cayetanensis infections have trended upward in the US since the 1990s, climbing from 537 confirmed cases in 2016 to more than 3500 by 2018 and ranging roughly between 1000 and 3000 cases in most years since, before this year's outbreak pushed counts well beyond that range. CDC now classifies cyclosporiasis as an important neglected parasitic infection and continues to recommend trimethoprim-sulfamethoxazole as first-line treatment for confirmed cases.^1-3

“The problem with bagged lettuce is that it says it's washed, but you cannot right now ensure it is. So buy heads of lettuce if you can. If you're buying lettuce, make sure you wash it well. If you're going to eat lettuce at a restaurant or at a gathering, it's important to ask about how it was prepared or to avoid it when you're not sure how the preparation went,” Catherine O’Neal, MD, chief academic officer for the Franciscan Missionaries of Our Lady Health System, previously told Contagion.⁴

The Taco Bell-linked cluster and the newly opened 72-case cluster are among several cyclosporiasis outbreaks CDC is tracking this summer, consistent with the disease's typical seasonal rise. This year's national case burden is running well ahead of any season in CDC's recent surveillance history.

References

1. Centers for Disease Control and Prevention. Investigation update: Cyclospora outbreak, July 2026. Updated July 16, 2026. Accessed July 23, 2026. https://www.cdc.gov/cyclosporiasis/outbreaks/07-26/investigation.html

2. Henderson B. CDC reports up to 7,000 cyclosporiasis cases across US, identifies large Midwestern outbreak cluster. Food Safety Magazine. Published July 15, 2026; updated July 23, 2026. Accessed July 23, 2026. https://www.food-safety.com/articles/11627-cdc-reports-up-to-7-000-cyclosporiasis-cases-across-us-identifies-large-midwestern-outbreak-cluster

3. US Food and Drug Administration. Investigation of 5-state outbreak of Cyclospora illnesses: iceberg lettuce (July 2026). Updated July 19, 2026. Accessed July 23, 2026. https://www.fda.gov/food/outbreaks-foodborne-illness/investigation-5-state-outbreak-cyclospora-illnesses-iceberg-lettuce-july-2026

4. O’Neal C, Contagion Editorial Team. The latest on the cyclosporiasis outbreak: an FDA false positive test, and what treatment looks like. ContagionLive. Published July 20, 2026. Accessed July 23, 2026. https://www.contagionlive.com/view/the-latest-on-the-cyclosporiasis-outbreak-recalled-products-and-what-treatment-looks-like