Infections caused by the diarrhea-inducing parasite, cyclospora, are witnessing an unprecedented increase throughout the United States. Data from more than 30 states suggest that 2026 is already the worst year for reported cases, surpassing the previous record of approximately 4,700 infections reported in 2019. The illness is not typically life-threatening and is often treated with antibiotics. However, health officials have yet to identify the definitive cause of the infections.
Federal health officials reported on Tuesday that while infection patterns differ across regions, there appears to be a connection among cases in Michigan, Ohio, Kentucky, and West Virginia.
Michigan’s Investigation Points to Lettuce
Michigan has reported over 3,300 cases. Early investigations suggest a possible link to lettuce or salad greens. Natasha Bagdasarian, chief medical executive of the Michigan Health Department, stated that interviews with over 1,000 patients revealed that lettuce frequently appeared during investigations.
Due to this commonality, Michigan officials advise consumers to purchase whole lettuce heads, discard outer layers, and wash thoroughly before consumption. They also recommend avoiding bagged lettuce and pre-mixed salad kits.
“Early information has shown lettuce as a common product that regularly comes up during the investigation,” said Natasha Bagdasarian.
Taco Bell has taken precautionary measures by temporarily removing certain ingredients from selected outlets. The chain will continue to monitor the situation and follow guidance from public health authorities.
Federal Investigation
Federal officials have yet to determine specific food vendors or distributors that could be linked to the outbreak. The FDA is conducting traceback investigations on multiple produce items. Donald Prater, Acting Deputy Commissioner for Food at the FDA, emphasized ongoing tracking.
Cyclospora: An Overview
Cyclospora is a microscopic parasite known for causing watery diarrhea with frequent bowel movements. According to the CDC, outbreaks occur most commonly in late spring and summer. The parasite infects the bowels and spreads through feces. In previous instances, contamination often occurred when fruits or vegetables were exposed to feces-contaminated irrigation water.
Cyclosporiasis is less common compared to other foodborne illnesses such as salmonella and E. coli. Historically, cyclospora cases might have been underreported, partly due to limitations in common food poisoning tests. Experts believe that climate change and enhanced detection methods contribute to the increased reporting of cases.
2019: Previous Record Year
The former record year for infections was 2019, with approximately 4,700 reported cases. The CDC tracks these numbers, which often lag behind real-time data from city and state health departments.
The CDC issued a health alert indicating that since May 1, they are aware of 1,645 confirmed domestic cases, with over 5,100 requiring further analysis to verify U.S. origins. Reports come from 34 states, with no reported deaths. The actual number of infections is suspected to be larger as milder cases may not seek medical care.
Symptoms can take days to weeks to develop post-exposure. The CDC anticipates that case numbers will rise through August.
Varied Sources of Infection
The CDC’s investigation into a multi-state outbreak affecting Michigan, Ohio, Kentucky, and West Virginia remains ongoing. Michigan officials suspect a linked domestic outbreak. However, Illinois, which reported over 200 cases, noted that more than half of the individuals had traveled abroad, possibly contracting the infection elsewhere.
CDC officials have yet to detail why cases in Kentucky, West Virginia, Michigan, and Ohio are believed to be part of the same outbreak.
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