Michigan’s cyclosporiasis outbreak continued its steep climb this week, with state health officials confirming Friday that the total case count has reached 10,773, an increase of 387 cases in a single day, according to the Michigan Department of Health and Human Services online dashboard.
The rapid rise has made Michigan the hardest-hit state in a multistate cyclosporiasis outbreak that has now spread to nine states nationwide. Cyclosporiasis is an intestinal infection caused by the microscopic parasite Cyclospora, which typically triggers watery diarrhea, nausea, cramping, fatigue and loss of appetite. Symptoms can persist for weeks if untreated, and health officials say the infection spreads primarily through contaminated food or water rather than person to person contact.
State data show that at least 193 people have been hospitalized statewide due to severe gastrointestinal complications tied to the outbreak, though no deaths have been reported so far. Federal investigators with the U.S. Food and Drug Administration have traced the source of the contamination to iceberg lettuce supplied by Taylor Farms operations in central Mexico, though authorities caution that other contamination sources may still be contributing to the spread of cyclosporiasis across the region.
The outbreak’s toll is increasingly visible at the county level in southern Michigan. Calhoun County remains the most significant hot spot, with confirmed cyclosporiasis cases climbing to 297. Hillsdale County has logged 57 infections, while St. Joseph County has reported 34 confirmed cases. Branch County, which had seen relatively few infections in recent weeks, recorded its first new case of the week, bringing its total to 15 confirmed cases.
Nationally, the scale of the outbreak appears larger than state tallies alone suggest. The Centers for Disease Control and Prevention reported 6,707 laboratory-confirmed cyclosporiasis cases since May 1 as of July 28, with more than 11,500 additional suspected cases still awaiting confirmation or further investigation. Officials note that CDC surveillance figures do not include probable cases, while state dashboards such as Michigan’s often combine probable and confirmed cases, which can result in higher published totals than the federal count.
Data from healthcare analytics firm Truveta underscore how unusual this summer’s surge has been. The rate of cyclosporiasis diagnoses this July was more than eleven times higher than the average recorded in July over the past eight years. More than one in five diagnosed patients ended up in an emergency department within two weeks of diagnosis, and nearly one in eight required hospitalization, the data show.
The outbreak has also had a measurable effect on consumer behavior. Grocery shoppers across the country have pulled back on lettuce purchases as concerns about food safety and uncertainty over which products remain safe continue to weigh on demand.
Former CDC officials and food safety experts say the government’s ability to respond has been complicated by recent cuts across federal health agencies, which they argue have strained the resources needed to trace and contain fast-moving foodborne illness outbreaks like this one.
Local health departments in the affected Michigan counties are continuing to urge residents experiencing persistent watery diarrhea and fatigue to contact their healthcare provider promptly and to cooperate with case investigators, who are working to identify additional sources of contamination and prevent further spread of cyclosporiasis. Health officials emphasize that early diagnosis and treatment with antibiotics can shorten the duration of illness significantly.
As the investigation continues, state and federal agencies say they will keep updating case totals daily as new lab-confirmed and probable cyclosporiasis reports come in from hospitals and clinics across Michigan and the other affected states.
