@michiganpublic Counties with the greatest number of reported cases (as of July 9, 2026): Monroe: 215 Wayne: 160 Washtenaw: 159 Lenawee: 105 Oakland: 88 Shiawassee: 82 38 other counties have been affected. ✈️ Cyclosporiasis is not a new illness, Dr. Bagdasarian said. In previous years, most cases have typically been associated with international travel. Cyclospora is one potential cause of “traveler’s diarrhea." 🛒 As of July 10, no specific grower, supplier, or produce type has been identified as the source of the outbreak. Contamination can occur in fields where produce is grown, or in the processing phase. Cyclosporiasis spreads via germs from contaminated human feces. 🍳According to MDHHS, heating food to at least 158°F kills Cyclospora. #parasite #outbreak #michigan #diseaseprevention #health #publichealth #news ♬ original sound - Michigan Public
An outbreak of cyclosporiasis has sickened thousands of people in the U.S., with Michigan having reported the most cases of any state. While health officials continue to investigate the outbreak's source, the Michigan Department of Health and Human Services has singled out the southeastern part of the state as seeing the largest increase in cases. As of Wednesday, July 15, the department's total reported cases stood at 3,762.
According to the CDC — which, amid federal funding cuts, recently made monitoring the parasite behind this illness optional among the 10 states that participate in its Foodborne Diseases Active Surveillance Network — cyclosporiasis stems from an infection of the bowel. It's caused by cyclospora, a parasite that can spread when people consume food or drinks that have been contaminated with feces. Infected persons can experience symptoms including watery diarrhea, nausea, fatigue, gas and bloating, loss of appetite, and weight loss.
To bring clarity surrounding cyclospora, from prevention to treatment, Michigan Public took a few frequently asked questions to Dr. Natasha Bagdasarian, the state's chief medical executive.
How should canned vegetables and frozen fruits be handled?
"Canned vegetables — those have actually been heated in the canning process — should be fine. [Canned] fruits and vegetables are considered safe," Bagdasarian said.
Frozen produce doesn't seem to be a major source of this outbreak, based on the data, so the state recommendations don't ask folks to avoid prepackaged frozen items. However, freezing temperatures will not reliably kill cyclospora. Cooking to at least 158 F is the safest option.
Is it necessary to wash the fruits you peel to eat?
"Rule of thumb is: if you have something that you are cutting into, in order to peel it, then that knife is taking things from the outside and moving them inside. So, yes, it is safer to wash the outside of those fruits," Bagdasaian said.
For fruits that are just peeled — like a banana, for example — she said washing isn’t necessary.
Washing does not reliably eliminate cyclospora from the surface of fresh produce, Bagdasarian added, but it is still good practice, especially when combined with peeling and cooking.
Is cross-contamination a major concern with cyclosporiasis?
Cross-contamination from bagged lettuce, as a result of contact with other foods in the fridge or on a plate, is not a major concern with this outbreak, Bagdasarian said. However, she suggested that washing or tossing potentially contaminated lettuce with other vegetables can be a source of cross-contamination.
Does cyclosporiasis pose a risk to pets?
"Cyclospora is typically not an animal disease," she said, adding that "this is something that, really, we have only confirmed in human hosts, so we don't believe that animals are a part of this outbreak or other cyclospora outbreaks."
Why is bactrim, an antibiotic, the standard treatment — as opposed to an antiparasitic, like mebendazole or ivermectin?
"Something like ivermectin actually works against parasitic worms, and it targets the nerve and muscle cells of these multicellular organisms. Cyclospora does not have those same components, it's a single-celled organism, so ivermectin has no target to act on," she explained. "Bactrim actually works by blocking folate, or vitamin B9, and that's a pathway that cyclospora needs to reproduce — the same way that some bacteria also use folate. So, blocking that folate is how bactrim works against this parasite."
What if I'm allergic to bactrim?
You should talk to your healthcare provider, as there are alternative treatments. Among them are ciprofloxacin, an antibiotic, and nitazoxanide, an antiparasitic. However, nitazoxanide is "typically less effective and has higher failure rates," she said.
Is there any kind of state assistance to help cover the cost of a cyclosporiasis test?
Routine stool tests sometimes fail to detect cyclospora, so reliable detection requires a different test. For some, the cost of that test can be quite high. But as of now, there is no state assistance specifically available to help cover these costs.
While Bagdsarian said providers can treat for cyclosporiasis — even without a positive test — empirically, or based on their "clinical suspicion," it is still preferred that people get tested for tracing purposes. She's a proponent of "open and honest" communication with your primary care provider, if cost or another factor creates reluctance around getting tested.
"I think being open about why you are reluctant to get tested is helpful. Sometimes your healthcare provider may not know that this is a huge out-of-pocket expense for you." She added that there are "other tests that can be done, like a stool ova and parasite exam," though it's "more likely to miss something like cyclospora," as a result of being "less sensitive."
For which groups is testing most imperative?
People with prolonged, watery diarrhea, as well as those with weakened immune systems, including:
- HIV/AIDS patients
- Organ recipients
- Those receiving treatment for cancer
- The very old and the very young
- Anyone having severe symptoms
Bagdasarian added that people in these groups, if advised to wait a bit before testing, should practice self-advocacy.
"If you fall into one of those categories and you're being told, 'No, we only test after seven days of symptoms,' I would sort of push a little bit and have more discussion about your risk factors and why you are concerned. Explain why you are concerned and what some of your risk factors are."
Because lettuce consumption is a common thread among those sickened, has official guidance changed?
While lettuce is not the definitive source of the outbreak, it is a product that regularly comes up during the investigations into reported cases.
"Now that doesn't necessarily mean that as the investigation goes on and as we interview more people, that we won't get more data," said Bagdasarian. "If we get more data, it's possible that there are other kinds of produce impacted as well. It's possible that the signals we are seeing about lettuce, you know, fade over time."
The recent guidance around consuming lettuce still stands:
- Wash all produce thoroughly under running water
- Buy whole heads of produce — instead of pre-washed, pre-bagged leafy greens — if possible
- Remove the outer layers from lettuce heads before cooking and consuming
- Cook to at least 158 F if the produce can tolerate the heat
Bagdasarian's parting words of wisdom: "If you can peel it, peel it. If you can cook it, cook it."
