Cyclosporiasis Outbreak Tops 11,500 Cases, Largest in US History

The United States is in the midst of its largest cyclosporiasis outbreak on record, with more than 11,500 cases identified this season across 41 states and a multistate cluster in the Midwest still actively expanding — even as investigators work to confirm the source and federal officials express confidence that the worst may be over.

How Big Is the Outbreak?

The CDC has identified 4,173 confirmed domestic cyclosporiasis cases this season, with roughly 7,400 additional cases undergoing further laboratory analysis. The large multistate cluster centered in the Midwest — linked to shredded iceberg lettuce from a Taylor Farms facility in central Mexico — has been formally connected to 1,644 cases, making it the largest single cyclosporiasis outbreak in US history. Previous large outbreaks rarely surpassed 1,000 cases. A 2023 USDA report identified a raspberry-linked outbreak at approximately 1,500 cases as the prior record.

Five states have confirmed cases linked to the current cluster: Michigan leads with 6,571 cases and 102 hospitalizations, followed by Ohio with 1,244 cases and 88 hospitalizations, Indiana with 511 cases, West Virginia with 195 cases and 15 hospitalizations, and Kentucky with 192 cases and 9 hospitalizations. No deaths have been reported. At least 94 people have been hospitalized specifically in relation to the current outbreak, with hundreds more across all cases this season.

Total US cyclosporiasis cases this year are significantly higher than in recent years. There were more than 4,500 cases in 2023 and more than 3,500 in 2024. This year’s count is already thousands higher, with at least a month of the typical May-to-August season remaining.

Taylor Farms Lettuce as the Likely Source — With Caveats

Michigan health officials said they have completed more than 2,000 interviews with confirmed patients and found “very strong” evidence linking the outbreak to shredded iceberg lettuce supplied by Taylor Farms and served at certain Taco Bell locations. Taylor Farms voluntarily recalled all iceberg lettuce from central Mexico on Friday and halted sourcing from the region for the rest of the growing season. Taco Bell removed Taylor Farms lettuce from its supply chain nationwide.

The recall has also extended to Walmart and Jack in the Box in 27 states. The CDC advises people not to eat any shredded iceberg lettuce from Taylor Farms de Mexico served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio, and West Virginia.

However, the investigation remains incomplete. No samples from the Taylor Farms facility have tested positive for cyclospora — a false positive result from the weekend was subsequently ruled out by FDA laboratory quality checks. Mexico’s health secretary has said his country’s investigation has not found evidence linking the outbreak to the facility. Michigan’s health department continues to note that other food sources cannot be fully excluded.

Illnesses tied to the current outbreak began in mid-May, with the most recent new cases reported as recently as last week. The CDC notes that “the true number of sick people in this multistate outbreak is likely higher than the number reported.”

What Other Foods Are Safe

The cyclosporiasis outbreak 2026 largest US record cases investigation has not implicated any foods other than iceberg lettuce in the current cluster. Romaine, cilantro, tomatoes, and other produce have not been linked to the outbreak. Foods historically associated with cyclospora outbreaks — including basil, cilantro, raspberries, and snap peas — are being monitored but are not part of the current advisory.

The FDA is working to determine whether contaminated lettuce from Taylor Farms reached destinations beyond Taco Bell, including food service operators.

Symptoms, Timing, and Treatment

Symptoms — including watery diarrhea, cramping, bloating, nausea, fatigue, and loss of appetite — typically develop two days to two weeks after consuming contaminated food. Illness can persist for weeks without treatment. Standard treatment is a seven-to-ten-day course of the antibiotic sulfamethoxazole-trimethoprim (Bactrim or Septra).

Broader Gastrointestinal Illness Picture

French biotech company bioMérieux, which tracks gastrointestinal pathogen trends across US labs, reports that cyclospora prevalence has surged from less than 3% of tests in mid-June to more than 18% in recent days. E. coli remains the most common culprit for stomach illness at present, appearing in more than 19% of tests, while viruses account for approximately 14% of positive gastrointestinal results.