The intestinal illness is believed to be tied to leafy greens and other fresh produce, with larger outbreaks also reported in Michigan and Ohio.
Nationwide Cyclosporiasis Outbreak Reaches 41 States with Over 4,000 Confirmed Cases
The gastrointestinal illness is caused by the microscopic single-celled parasite Cyclospora cayetanensis. Symptoms typically develop one to two weeks after a person consumes contaminated food or water, making the source difficult to trace. The illness is not spread directly from person to person. While most patients make a full recovery, symptoms can persist for weeks and include explosive, watery diarrhea, severe abdominal pain, nausea, vomiting, fatigue, loss of appetite, and weight loss. Some patients may require treatment with antibiotics. Dehydration caused by severe diarrhea can be particularly dangerous for vulnerable groups, including young children, older adults, pregnant individuals, and immunocompromised people.
Regulatory Challenges and Difficulties in Tracking the Parasite
Federal health authorities and researchers point out that regulatory and biological factors make outbreaks exceptionally hard to track and contain. Unlike many bacteria, Cyclospora does not grow in laboratory culture, and state laboratories often lack the specialized tools to identify it quickly.
Furthermore, industrial processing safeguards offer limited protection against the parasite. Products like chlorine, which processing plants normally rely on to disinfect items, have essentially no effect on Cyclospora. The only reliable way to kill or inactivate the parasite is with heat—reaching temperatures around 160°F according to Johns Hopkins University experts, or at least 158°F according to University of Minnesota Extension Educator Autumn Stoll—which is not a practical option for fresh salad greens, herbs, raspberries, and other produce typically associated with these outbreaks.
Experts note that the food system relies heavily on Hazard Analysis Critical Control Points, or HACCP, an approach originally developed in the late 1950s by NASA and Pillsbury to map out choke points from farm to fork. However, enforcement has eroded over time, leaving the country more vulnerable to foodborne illness.
State-Level Impacts and Separate Lettuce Investigations
Federal health authorities have also been investigating a separate multi-state Cyclospora outbreak linked to iceberg lettuce. That separate investigation sickened 1,947 people across nine states—including Pennsylvania—prompting Taylor Farms to recall iceberg lettuce sourced from central Mexico. Although an initial laboratory test detected Cyclospora on recalled lettuce, the U.S. Food and Drug Administration later determined the result was a false positive. The CDC’s nationwide count of 4,173 cases is separate from this lettuce-linked investigation.
In Pennsylvania, the state health department reported between 24 and 28 cases in 2026, following 40 reported cases in 2025 and 87 cases in 2024. Roughly half of Pennsylvania’s 2026 cases have been identified in the southeastern part of the state, which includes the Philadelphia metropolitan area. Philadelphia health officials noted that the city’s individual case count has remained within its normal seasonal range and did not experience an unusual spike. Because cyclosporiasis is not among Pennsylvania’s mandatory reportable diseases and healthcare providers report infections voluntarily, actual infection numbers may be higher than official figures. Meanwhile, Minnesota has reported no confirmed outbreak clusters, though infections have been recorded across 41 states.
Guidance for Consumers on Produce Safety
Public health educators emphasize that consumers do not need to skip fresh fruits and vegetables or avoid all lettuce.
* Thoroughly rinse fresh fruits and vegetables under running water before eating. * Scrub firm produce, such as cucumbers, with a clean produce brush to help remove dirt and potential contaminants. * Retain product packaging, which contains brand names, lot numbers, and purchase details to help determine if an item is subject to a food recall.
