Cyclosporiasis Cases Surpass 3,000 as Michigan Identifies Lettuce and Salad Greens as Potential Source

Michigan health officials reported more than 3,000 cases of cyclosporiasis as of July 13, 2026, with infections concentrated in southeast counties including Wayne, Oakland, and Washtenaw. The state’s Department of Health and Human Services said preliminary testing identified lettuce and salad greens as a potential source of the outbreak, though no specific grower or supplier has been confirmed.

The infections are concentrated primarily in southeast Michigan counties including Wayne, Oakland, Washtenaw, Monroe, Lenawee, Shiawassee, Jackson, Ingham, and Livingston, according to state updates and local health reports. The department described the situation as a growing outbreak and emphasized that investigations are ongoing.

The Michigan Department of Health and Human Services (MDHHS) reported a rapid increase in cyclosporiasis cases, rising from 1,562 on July 10 to 2,640 by July 13, 2026, indicating a significant escalation in the outbreak over a short period.

Preliminary testing by MDHHS has identified lettuce and salad greens as a potential source of the outbreak, though officials have not yet confirmed any specific grower, supplier, or produce type linked to the cases. Dr. Natasha Bagdasarian, Michigan’s chief medical executive, stated that while no definite product has been identified, early information shows lettuce as a common item associated with the investigation. MDHHS also noted that other food items have not been ruled out and that the findings remain preliminary.

The department issued public guidance on July 4, 2026, to help prevent foodborne illness amid the outbreak. This included recommendations to buy whole heads of lettuce rather than prewashed bagged lettuce or salad mixes, discard the outer two to three layers of leaves, and wash inner leaves under running water. For leafy greens that can be cooked, MDHHS advised that cooking is the safest option, as heating food to 158 degrees Fahrenheit (70 degrees Celsius) or higher kills Cyclospora parasites. Consumers were also urged to wash all fresh produce thoroughly, even if it will be peeled later.

Cyclospora infection typically causes watery or severe diarrhea, stomach cramps, and nausea, according to local health reports linked to the outbreak. Treatment involves antibiotics, along with rest and adequate hydration, officials said. MDHHS urged those experiencing symptoms to contact their health care provider and local health department. The department also recommended handwashing with soap and water before and after handling food and sanitizing utensils, cutting boards, refrigerators, and produce display cases to reduce the risk of contamination.

The outbreak timeline shows a sharp increase in cases over recent weeks. On June 30, 2026, local reports indicated 572 cases, up from 170 earlier that week. By July 4, MDHHS had issued its initial public recommendations, and on July 5, the department confirmed that no specific grower or supplier had been identified. State bulletins on July 7 reported 784 cases clustered in multiple southeast Michigan counties, with numbers continuing to climb sharply through mid-July.

MDHHS highlighted that several foods have been linked to previous Cyclospora outbreaks in the U.S. and Canada, including bagged salad mixes and kits, fresh cilantro, fresh basil, raspberries, snow peas, and green onions. The department’s guidance specifically noted bagged salad mixes and kits as pre-cut lettuce blends associated with earlier outbreaks and identified lettuce and leafy greens as foods requiring special caution during the current investigation.

The department maintained an active investigation status as of the latest updates, with source identification still incomplete. Officials continue to monitor the outbreak and update the public through the MDHHS Cyclosporiasis Outbreak 2026 webpage. The department’s ongoing efforts include testing potential sources and coordinating with local health agencies to track new cases and provide updated guidance.