What’s causing the sudden cyclospora outbreak in Michigan? Officials investigating 174 cases; details
Michigan health officials are investigating an unusually large incident outbreak Between June 22 and 30, 2026, 174 cases of cyclosporiasis were reported in southern Michigan. The disease is caused by parasites Cyclospora cayeta and may cause stomach-related symptoms, including severe diarrhea.
According to the Michigan Department of Health and Human Services (MDHHS), the number of infections reported in a little more than a week is far higher than the state typically sees throughout the entire year. Officials have not determined the source of the outbreak but expect more cases to be reported as the investigation continues.
Michigan searches for source of outbreak
The epidemic is concentrated in several areas in the south michigan counties, with Monroe County reporting the highest number of cases. State data shows there are 70 cases in Monroe County, 33 in Lenawee County, 21 in Washtenaw County, 12 in Wayne County and seven each in Jackson and Hiawassee counties. An additional 24 cases have been recorded in 11 other counties and the city of Detroit.
MDHHS spokesperson Lynn Sutfin said health officials are still working to determine the source of the infection. “Individuals concerned about sudden gastrointestinal illness should contact their health care provider,” Sutfin said on behalf of the department.
Cyclospora infection can be treated with antibiotics, as can people with diarrhea or diarrhea Vomit People are encouraged to stay hydrated, especially during the high temperatures expected this week. “
The Michigan Department of Agriculture and Rural Development is also assisting with the investigation. The agency advises residents to wash fresh produce carefully, remove damaged parts of fruits and vegetables, and refrigerate produce after cutting.
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CDC explains symptoms and spread of cyclosporiasis
according to Centers for Disease Control and Prevention (Centers for Disease Control and Prevention) Symptoms may appear anywhere from two days to two weeks after infection. The disease usually causes watery diarrhea and sometimes frequent or explosive bowel movements. Other symptoms may include nausea, vomiting, stomach cramps, bloating, low-grade fever, loss of appetite, and weight loss.
Centers for Disease Control and Prevention says parasites Usually spread through contaminated food or water. Human-to-human transmission is considered unlikely. Several outbreaks in the United States in recent years have been linked to contaminated fresh produce, particularly during the summer.
The recent surge is notable because Michigan has reported relatively low numbers of cyclosporiasis cases in recent years. National surveillance records show 56 cases in 2022, 43 in 2023, 41 in 2024 and 54 in 2025.
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This growth isn’t limited to Michigan. Just south of the state line, the Toledo-Lucas County, Ohio, health department reported about 65 cases as of Wednesday morning. Michigan health officials said the current cases involve patients between the ages of 8 and 84, with a median age of 41.
