LANSING, Mich. — Michigan health officials said a rapidly expanding outbreak of cyclosporiasis has surpassed 300 confirmed cases, far exceeding the state's typical annual total, as investigators work to identify the source of the foodborne parasitic illness.
The Michigan Department of Health and Human Services (MDHHS), working with the Michigan Department of Agriculture and Rural Development (MDARD) and local health departments, said the outbreak has affected residents in Monroe, Lenawee, Washtenaw, Wayne, Livingston, Shiawassee and Jackson counties, with additional cases reported elsewhere in the state. Officials said no common source had been identified as of Saturday, and the investigation remains ongoing.
State officials first announced the outbreak on July 1 after more than 170 cases were identified within nine days. The case count has since climbed beyond 300, compared with Michigan's usual average of about 50 cyclosporiasis cases in an entire year.
"Based on the unusual number of cases we have identified in a little over a week, we anticipate additional cases of illness being reported," MDHHS Chief Medical Executive Dr. Natasha Bagdasarian said in the department's earlier outbreak announcement. She urged residents experiencing persistent diarrhea to seek medical evaluation and contact local health authorities if multiple household members become ill.
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis, which spreads through food or water contaminated with fecal matter. According to health officials, the illness is not known to spread directly from person to person. Symptoms typically develop two to 14 days after exposure and can include frequent watery diarrhea, abdominal cramps, bloating, nausea, fatigue, weight loss and low-grade fever. Antibiotic treatment can significantly shorten the illness, which may otherwise persist for weeks.
MDARD said it is assisting investigators in tracing the outbreak while reminding consumers to follow food safety practices, including washing fresh produce under running water, refrigerating cut fruits and vegetables promptly, and maintaining good hand hygiene during food preparation. Officials also urged people diagnosed with cyclosporiasis to cooperate with public health interviews to help identify possible common exposures.
The outbreak comes as federal health authorities investigate multiple clusters of domestically acquired cyclosporiasis cases reported in several U.S. states. The U.S. Centers for Disease Control and Prevention has said investigators have not linked all reported illnesses to a single nationwide source and that traceback efforts remain underway.
Michigan health officials said they expect additional cases to be reported while the investigation continues and have not announced any food recalls or identified a specific contaminated product.
