LANSING — The Michigan Department of Health and Human Services said Monday that its investigation into a statewide outbreak of cyclosporiasis is pointing toward lettuce or salad greens as a likely vehicle of infection, though officials cautioned no single product, grower or supplier has been definitively identified.
The outbreak, which began in late June, has grown to 2,640 confirmed cases across the state and has required more than 40 hospitalizations, according to MDHHS. For context, Michigan typically records roughly 50 cyclosporiasis cases in a year.
What officials are saying
MDHHS Chief Medical Executive Dr. Natasha Bagdasarian urged Michiganders to take prudent steps while the probe continues.
"Although we do not have a definite product identified as the source of the outbreak, we want to let Michiganders know what we have learned so far so they can take steps to protect their families," Dr. Bagdasarian said in a release.
State health investigators reported that interview data and preliminary findings show lettuce — including products that commonly appear in pre-washed or pre-mixed packaged salads — has frequently come up during case investigations. Officials emphasized other foods cannot be ruled out at this point.
Symptoms, incubation and investigation challenges
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis. The infection often produces gastrointestinal symptoms, including severe diarrhea that can come on suddenly. Specialists note the incubation period typically ranges from one to two weeks, which complicates efforts to trace exposures through the nation’s wide-reaching fresh produce distribution networks.
Dr. Ambreen Malik, an infectious disease specialist at University of Michigan Health Sparrow, told investigators that the prolonged incubation period and the fact that produce is sourced from numerous domestic and international suppliers make pinpointing a single contaminated product difficult.
Practical steps for consumers
MDHHS offered specific guidance for residents while the investigation continues:
- Prefer buying whole heads of lettuce rather than pre-washed, bagged or pre-mixed salad kits.
- Discard the outer two to three layers of leaves on whole heads of lettuce and thoroughly wash the inner leaves.
- For greens that can be cooked, heat them to at least 158 degrees Fahrenheit.
Health officials are also monitoring reports of related cases in other parts of the country, including states in the Midwest. The interstate nature of produce supply chains means the investigation is being coordinated with federal partners and other jurisdictions.
Local impact and what to watch for
Clinicians advise residents with persistent or severe gastrointestinal symptoms to seek medical care. Laboratory testing can confirm cyclosporiasis, and treatment typically requires prescription medication.
| Metric | Reported |
|---|---|
| Current confirmed cases in Michigan | 2,640 |
| Hospitalizations | More than 40 |
| Typical annual cases in Michigan | About 50 |
As the MDHHS continues interviews, laboratory testing and supply-chain tracing, residents should follow official updates from state health authorities for newly identified risks, recalls or additional consumer guidance. Local public health departments remain available to answer questions from the public and clinicians handling possible cases.
This report will be updated as health officials release new findings from the ongoing investigation.
