Infections caused by cyclospora, a parasite responsible for diarrhea, are increasing significantly in the United States. Current data indicates that 2026 could be the worst year on record for reported cases, surpassing the previous high of approximately 4,700 infections in 2019.
Rising Infections Across the Nation
More than 30 states have reported cases this year. Federal health officials have noted potential patterns of infection varying by location, with identified links in Michigan, Ohio, Kentucky, and West Virginia.
Michigan officials suspect lettuce
In Michigan, over 3,300 cases have been reported. Officials have conducted upward of 1,000 interviews, leading them to suspect salad greens or lettuce as potential sources. Natasha Bagdasarian, Chief Medical Executive of the Michigan Health Department, confirms that lettuce frequently surfaces in their investigation.
Consumers in Michigan are advised to purchase whole heads of lettuce, discard outer layers, and thoroughly wash the leaves. Bagged lettuce and pre-mixed salad kits are not recommended due to past cyclospora outbreaks linked to produce.
Response From Restaurants and Vendors
Taco Bell has proactively removed certain ingredients from select locations as a precaution, stating continued monitoring and adherence to public health guidance.
The U.S. FDA, led by Acting Deputy Commissioner for Food Donald Prater, is actively tracing multiple produce sources reported by affected patients.
Understanding Cyclospora
Cyclospora is a microscopic parasite causing watery and occasionally severe diarrhea. The U.S. Centers for Disease Control and Prevention note its outbreaks often happen in late spring and summer. Spread occurs through fecal contamination.
Historically less common than illnesses like salmonella and E. coli, cyclospora started rising notably around 2018. Experts attribute this to improved detection and climate change impacts.
Record Year for Cyclospora
2019 saw approximately 4,700 reported cases, marking the worst year until now. As of May 1, 2026, CDC reports 1,645 confirmed domestic cases alongside over 5,100 suspected ones. These figures come from 34 states, and no deaths are reported.
CDC’s Gwen Biggerstaff highlights that many infections are likely underreported, as milder cases often go unrecorded. Symptoms may not appear until days or weeks post-exposure, thus complicating the tracking of current infection rates.
While Michigan, Ohio, Kentucky, and West Virginia are linked to a common outbreak, Illinois has instances of travelers infected outside the U.S., indicating varied sources.
The CDC foresees continued growth of case numbers through August. Detailed data from individual states is still developing, with Michigan reporting notably high figures compared to other regions.