The gastrointestinal illness cyclosporiasis continues to spread across Michigan, with state health officials reporting nearly 700 cases as of Monday — up from about 170 last week, and more than 10 times more than the approximately 50 cases reported in a typical year.
Cyclosporiasis is typically contracted by eating fresh produce contaminated with the microscopic parasite Cyclospora cayetanensis. The specific source of the current outbreak has not yet been identified, but the Michigan Department of Health and Human Services said past outbreaks have been linked to the following items:
- Bagged salad mixes
- Raspberries
- Green onions
- Snow peas
- Fresh basil
- Fresh cilantro
"Be aware of those products in particular, but also just any produce where it's really hard to wash it," said Dr. Natasha Bagdasarian, the state's chief medical executive. "Raspberries, for example, there are all those nooks and crannies, and so they can be particularly difficult to wash."
The state health department said Michigan residents should cook produce when possible and wash fruits and vegetables thoroughly — even when not eating the peel or rind.
The highest case counts are concentrated in counties around Southeast Michigan, including Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland and Livingston, according to health department data.
Health officials have not reported any deaths from the disease in the state.
Cyclosporiasis symptoms typically occur two to 14 days after exposure and often include watery diarrhea, explosive bowel movements, abdominal cramps and bloating, and loss of appetite.
Untreated cyclosporiasis can last for weeks and lead to intestinal damage. However, for most people, the parasite can be easily treated with antibiotics. State health officials advise residents to seek medical care and testing if they suspect they have the parasite.
Bagdasarian said local health departments are working to interview every patient to try to determine what they ate and where it came from. That information is then entered into a statewide database to look for patterns.
"There's a lot of tracing back that we have to do in terms of not just where people got their produce from, but then tracing that back to its very origins and finding where along that pathway the contamination occurred," Bagdasarian said.
She also said the state's public health labs were doing "very advanced" whole genome sequencing on stool samples from patients. By comparing genetic markers, scientists can see whether the samples are genetically identical, which can indicate that patients were part of the same outbreak or exposed to the same contaminated food item.
Michigan's outbreak comes as cyclosporiasis cases have been recorded in 17 other U.S. states. Bagdasarian said Michigan is working with the Centers for Disease Control and Prevention and other national partners to monitor the outbreak and track how contaminated products might be moving through complex national and international food distribution networks.
"We can't just think about food safety as a Michigan issue," Bagdasarian said. "We have to really think about these food distribution networks, where much of our produce is coming in from other states or other countries, and how it's handled at multiple steps, and all of that really plays a role in how safe we are."
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