Michigan’s cyclosporiasis outbreak has reached about 1,000 cases, making it the largest in the state’s history and one of the nation’s biggest in recent years. The state typically reports about 50 cases per year.

According to GDELT, no deaths have been reported and about 40 hospitalizations have occurred, while the source of the Cyclospora infections has not been identified. The CDC says Cyclospora commonly causes watery diarrhea with frequent, sometimes explosive bowel movements. Cyclosporiasis is a form of food poisoning caused by the parasite Cyclospora cayetanensis; symptoms usually start within a week of ingesting the parasite, and the main symptom is watery diarrhea.

Investigations into similar illnesses have been ongoing in 28 other states, including Ohio, according to GDELT. Seventeen states have confirmed cyclosporiasis cases, including Illinois, Maryland, Massachusetts, New York and Texas, also reported by GDELT. Lucas County, Ohio, reported 306 cases as of Wednesday (GDELT), and Ohio reported 177 cyclosporiasis cases as of 2 July (The Guardian).

My.ClevelandClinic.org notes that there were over 1,000 cyclosporiasis cases in the United States in 2025. The parasite is more common in tropical or subtropical parts of the world and in areas that do not have widespread water treatment.