Wisconsin Faces Explosive Diarrhea Outbreak

As of Tuesday, July 7, 2026, Wisconsin has reported 35 cases of an intestinal illness linked to the Cyclospora parasite. This figure represents nearly double the number of cases recorded by this date in the previous year, signaling a substantial increase in the current cyclosporiasis season.

The state Department of Health Services believes that international travel is the primary factor contributing to this rise. Fewer than ten of the reported cases were associated with individuals who had not traveled internationally, suggesting that domestically acquired cases are within expected seasonal ranges.

Wisconsin's neighbors are also experiencing high numbers of cyclosporiasis cases. Illinois has reported 141 cases, while Michigan has documented over 700. These figures indicate a broader regional issue beyond Wisconsin's borders.

Cyclosporiasis is an intestinal infection caused by the microscopic parasite Cyclospora cayetanensis. Symptoms typically include watery diarrhea, frequent and sometimes explosive bowel movements, loss of appetite, fatigue, and stomach cramps. Less common symptoms can include vomiting, body aches, headache, and low-grade fever. The incubation period usually ranges from two days to over two weeks, and the illness can persist for over a month without treatment.