Michigan sees over 300 cyclosporiasis cases as outbreak spreads across the US

State health officials in southeast Michigan have confirmed more than 300 cases of cyclosporiasis within a week, far exceeding the roughly 50 cases the state typically records each year. The outbreak, caused by the Cyclospora cayetanensis parasite, is characterized by watery, often "explosive" diarrhea, abdominal cramps, nausea, fever and weight loss. Affected individuals range from 8 to 84 years old, with a median age of 41.

Cases have been identified in at least 21 Michigan counties, most notably Monroe (92 cases), Lenawee, Washtenaw, Wayne and others, and the disease has now been reported in 18‑20 other states, bringing the U.S. total to over 400 infections and more than 20 hospitalizations. The CDC, together with the FDA and state health departments, is investigating the source, but no single food, grower or supply chain has been identified. Historically, cyclosporiasis outbreaks have been linked to fresh produce such as bagged salads, cilantro, basil, raspberries, snow peas and other leafy greens.

Officials advise consumers to wash all fruits and vegetables thoroughly, discard damaged portions, and cook produce when possible. The parasite is transmitted through food or water contaminated with feces and requires one to two weeks outside the body to become infectious, making person‑to‑person spread unlikely.