Cyclospora infections hit record high in 2026, Michigan officials suspect lettuce as source

Infections caused by the parasite Cyclospora have surged to a record level in 2026, with more than 30 states reporting cases that now exceed the previous U.S. high of about 4,700 set in 2019.

The illness typically produces diarrhea and is not usually life‑threatening, and patients are generally treated with antibiotics.

Health officials have not yet confirmed a single source, but they note that infection patterns may vary by region. Cases in at least four states – Michigan, Ohio, Kentucky and West Virginia – appear to be linked.

In Michigan, where over 3,300 cases have been recorded, investigators who have conducted more than 1,000 patient interviews say lettuce or other salad greens are the product most frequently mentioned as a possible culprit.