Cyclosporiasis outbreak surges to 18,000+ cases across 45 U.S. states and UK

A cyclosporiasis outbreak has expanded to more than 18,000 cases across 45 U.S. states as of late July 2026, marking the largest outbreak of the parasitic illness in U.S. history. The Centers for Disease Control and Prevention reported at least 6,707 laboratory-confirmed infections and 423 hospitalizations, with an additional 11,500 probable cases under investigation. The outbreak, driven primarily by contaminated iceberg lettuce from Taylor Farms de Mexico, has spread across nine states with confirmed links to the produce: Indiana, Kentucky, Michigan, Ohio, West Virginia, Illinois, Kansas, Oklahoma, and Pennsylvania. Michigan has been the hardest-hit state, reporting over 9,200 cases as of late July.

Federal investigators traced the primary outbreak to shredded iceberg lettuce supplied by Taylor Farms and served at Taco Bell restaurants beginning in late June 2026. Taylor Farms voluntarily recalled all iceberg lettuce sourced from central Mexico on July 17. The FDA initially reported finding cyclospora on Taylor Farms lettuce samples over the weekend of July 19-20, but retracted that finding on July 21, stating it was a false positive. Despite the retraction, epidemiological evidence—including interviews with more than 1,900 infected individuals who reported eating at Taco Bell—continued to support the lettuce as the outbreak source. Mexican health authorities visited the Taylor Farms facility in Guanajuato between July 18 and 20, collecting samples but finding no parasite or contamination in the lettuce or water.

The FDA is simultaneously investigating at least five additional cyclospora outbreaks nationwide. A sixth outbreak cluster of 72 cases was announced on July 23 with no identified source. Overall, the agency has received reports of more than 11,500 confirmed and probable cases since May 1, 2026, far exceeding the typical U.S. annual caseload of 2,000 to 5,000 cases. Symptoms include watery diarrhea, loss of appetite, weight loss, and cramping, typically beginning one week after infection and lasting weeks without treatment. No deaths have been reported.

UK health authorities have also reported a sharp rise in cases linked to travel. The UK Health Security Agency documented 67 cases between April 30 and July 15, 2026, with 48 of 52 cases with travel information involving travelers who stayed in resorts in the Riviera Maya or Cancún regions of Mexico. The UKHSA anticipates continued increases as summer travel continues.

Cyclosporiasis is caused by a microscopic parasite that enters food through contamination with human feces, most commonly via contaminated irrigation or wash water. Cyclospora has only ever been found in human feces, yet investigators have historically struggled to identify how contamination enters agricultural systems. Food safety experts note that investigations are complex because symptoms can take up to two weeks to appear, making it difficult for patients to recall exposures. The investigation is expected to progress slowly over coming weeks.