Michigan Cyclospora Outbreak Spreads to Multiple US States

Health officials report a rapidly expanding outbreak of cyclosporiasis, an intestinal illness caused by the Cyclospora parasite. Michigan’s cases have surged from a typical annual total of about 50 to more than 700 confirmed infections since late June 2026, concentrated in Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland and Livingston counties. Ohio has documented 177 cases across 43 counties, while the CDC’s national surveillance shows at least 145 cases in 17 states, with hospitalizations ranging from 20 to 36 and no deaths.

The source of the outbreak remains unidentified; investigators suspect contaminated fresh produce but have not linked any specific grower, supplier or food item. Standard stool cultures do not detect Cyclospora, requiring a targeted acid‑fast stain or PCR test. Symptoms include explosive watery diarrhea, abdominal cramping, nausea, fatigue and weight loss, lasting from days to weeks if untreated. The CDC has issued warnings for the summer “Cyclospora season” and advises thorough washing of fruits and vegetables, cooking produce when possible, and seeking medical care for persistent diarrhea.

State health departments in Michigan, Ohio, Texas, North Carolina, New York, Illinois and others are issuing guidance to restaurants and consumers. Ongoing investigations aim to trace common exposures through patient interviews, receipt reviews and environmental testing, but no single product has been confirmed as the source.