Nearly a thousand people in Michigan are currently dealing with a parasitic infection that causes, and we are quoting the CDC here, "frequent and sometimes explosive bowel movements." It is the largest cyclospora outbreak in Michigan state history, it has spread into Ohio, and investigators have no idea what food is causing it. Great summer, everybody.
The Numbers Are Bad and Getting Worse
Michigan health officials first flagged this outbreak last week, when they had counted a little over 170 cases, all clustered in the southeastern corner of the state, dating back to June 22. Michigan normally sees about 50 cyclospora cases in an entire year. So this was already alarming.
By Wednesday, CBS News reports, that number had exploded to 992 confirmed cases with roughly 40 hospitalizations. Right across the state line, Lucas County, Ohio logged 306 cases on its own, with northwest Ohio as a whole crossing 400. The CDC has confirmed cases in 17 states total, from Illinois to Maryland to Massachusetts to New York to Texas, with investigations into similar illnesses running in 28 states.
To put the scale in context: CBS News found that in the last 20 years, only a handful of documented outbreaks have exceeded 1,000 cases nationwide. Michigan is nearly there by itself. This is not a normal summer stomach bug situation.
So What Exactly Is Cyclospora?
Cyclospora is a microscopic parasite that infects the intestines and spreads through feces-contaminated food or water. The illness it causes, cyclosporiasis, hits you with watery diarrhea, cramping, bloating, nausea, loss of appetite, weight loss, and fatigue. In worse cases, vomiting, body aches, headache, and fever join the party. It is not usually fatal, but it is absolutely miserable, and it can drag on for weeks.
The parasite loves warm weather, which is why outbreaks cluster in late spring and summer. Past U.S. outbreaks have been linked to bagged salad mixes, fresh cilantro, fresh basil, raspberries, snow peas, and scallions, according to the Michigan Department of Health and Human Services. The contamination typically comes from irrigation water tainted with feces, which is exactly as grim as it sounds.
The good news, such as it is: the CDC says cyclospora does not spread person to person, and the infection can be treated with antibiotics. It is not a national health emergency. But tell that to the nearly thousand Michiganders currently experiencing what the CDC diplomatically calls "explosive bowel movements."
Nobody Knows What Food Is Causing This
Here is the part that should make you nervous about whatever you ate for lunch. Investigators have not identified the source. Not even close. The Michigan Department of Health and Human Services, the CDC, and the FDA are all involved, and the FDA's statement Wednesday night was that its investigation was "ongoing," which is the federal agency equivalent of a shrug emoji.
Figuring out the source of a cyclospora outbreak is genuinely difficult, and CBS News talked to researchers who explained why. Labs cannot grow the parasite in controlled conditions, which eliminates a key tool for tracing contaminated food. The culprit is often a single ingredient like cilantro or basil, something that shows up in dozens of dishes across grocery stores and restaurants, making it nearly impossible for sick people to pinpoint where they got it. And food distributors might send contaminated product to both grocery chains and restaurant suppliers simultaneously, scattering the evidence.
Melanie Firestone, a foodborne illness researcher at the University of Minnesota, told CBS News there is also massive underreporting baked into this problem. Many standard food poisoning tests are not designed to detect cyclospora specifically, so a significant chunk of cases simply never get counted. Investigations like this one can take months and sometimes never reach a definitive answer.
This Is Part of a Bigger, Worsening Trend
Cyclospora outbreaks used to be rare. For years, only a handful were reported annually in the United States. Then, about a decade ago, the numbers started climbing, with a particularly sharp spike in 2018 and 2019. The CDC's acting parasitic diseases branch chief, Dianna Blau, told CBS News there is no evidence the parasite itself has evolved to be more infectious. Experts attribute the rise to a combination of climate change and better detection methods.
This year's case count is already four times higher than at the same point last year, according to current CDC national data, which CBS News notes runs significantly behind what states are actually reporting in real time. The CDC's Blau acknowledged it is not yet clear how unusual the full year will be once all the numbers catch up.
Michigan's chief medical executive, Dr. Natasha Bagdasarian, made a fair point to the Associated Press: the state's aggressive investigation and reporting practices may be making this look more like a Michigan crisis than a national one. Other states with less robust surveillance infrastructure may have clusters they haven't found or fully counted yet. Which is either reassuring or deeply alarming, depending on your perspective.
What You Should Actually Do
If you have diarrhea that is not resolving on its own after a few days, health officials say you should see a doctor and specifically bring up cyclospora, because again, standard tests often miss it. Stay hydrated. If you are diagnosed, antibiotics work.
Beyond that, the standard food safety advice applies, even if it feels hollow when nobody has identified what food to avoid: wash your produce thoroughly, pay attention to any recalls that come out of this investigation, and watch for updates from the CDC and your state health department. If you are in Michigan or northwest Ohio, that advice goes double right now.
The Dingo Take
Let's be honest about what "the FDA's investigation is ongoing" means in the summer of 2026. It means the agency responsible for making sure your salad doesn't give you explosive diarrhea for three weeks is understaffed, under-resourced, and operating in a political environment where the very concept of federal food safety oversight has been treated like a luxury we can't afford. The FDA's statement Wednesday night was boilerplate. Nearly a thousand people sick in one state, 28 states under investigation, and the agency's public response was essentially "we are aware of the situation and are working with stakeholders." Cool.
The underlying science here is genuinely hard, and to be fair to the investigators, cyclospora is a nightmare to trace. But "hard" and "impossible" are different things, and the long-term trend of more frequent, larger outbreaks tied to a warming climate is not a mystery. We know why this is getting worse. The political will to do something serious about food safety infrastructure, farm labor conditions, irrigation water quality, and supply chain transparency is a different question entirely, and that one has a much simpler answer.
For now, nearly a thousand people in Michigan are sick, nobody knows from what, and the government's posture is essentially "stay tuned." If you were hoping for a reassuring conclusion here, you are reading the wrong website.
