The Centers for Disease Control and Prevention is grappling with a surge in cyclosporiasis cases, a parasitic illness that triggers severe gastrointestinal distress, including explosive diarrhea. As of Friday, the agency has recorded 843 confirmed infections across 31 states, with 86 hospitalizations. But the CDC acknowledges the actual number is likely far higher, noting that over 1,500 additional cases are under review and that state reports often exceed federal counts.
Michigan remains the epicenter of the outbreak, with state health officials reporting 2,640 cases as of Monday, including 44 hospitalizations. The spike has drawn attention to the state's public health infrastructure and prompted questions about food safety. In a related development, Michigan's cyclospora cases are nearing 1,000 in what experts call an unprecedented outbreak, though the official tally now far exceeds that mark.
What Is Cyclosporiasis?
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis, which is rare in the United States. It spreads through food or water contaminated with feces. While travelers sometimes pick up the parasite abroad, the current cases involve people who had not traveled outside the U.S. in the two weeks before becoming ill. Domestically, outbreaks are often traced to fresh produce such as romaine lettuce, basil, cilantro, snow peas, and raspberries. The CDC is actively investigating the source of this outbreak, and the cyclospora outbreak has surged past 1,000 cases as the CDC investigates contaminated produce.
Geographic Spread
According to a Nexstar review of state health data, at least 39 states have reported at least one cyclosporiasis case this year. However, reporting methods vary: some states release year-to-date figures, while others cover only recent months. The CDC reports only confirmed cases, but many states also track probable infections. The map of confirmed cases shows a broad geographic distribution, with Michigan leading by a wide margin.
Patients range in age from 5 to 88 years old among domestically acquired cases. An additional 343 cases across 32 states involve people who ate or drank outside the U.S. within two weeks of symptom onset; 18 of those required hospitalization.
Symptoms and Severity
Not everyone infected develops symptoms, but those who do often experience frequent, watery diarrhea that can be loud and explosive. Other symptoms include loss of appetite, nausea, vomiting, stomach cramps, bloating, low-grade fever, and extreme fatigue. Symptoms typically appear two days to two weeks after exposure.
Dr. Katie Theoktisto of Baylor Scott & White told Nexstar that while some patients recover on their own within a few days, those with diarrhea lasting more than a week should seek medical care. A stool test is required for diagnosis. Young children, pregnant women, the elderly, and immunocompromised individuals face higher risks of severe illness or symptom recurrence.
One Southern California woman who recovered from cyclosporiasis described it as “the sickest I’ve ever been,” telling Nexstar’s KTLA that she suffered intense stomach pain and was unable to keep food down. “It was coming out of both ends,” she said. After several days on antibiotics, she began to feel better, adding, “I would not wish that on my worst enemy.”
The CDC continues to urge caution, especially for those handling fresh produce. While the agency has not identified a single source, the outbreak's scale suggests a widespread contamination event. As the investigation unfolds, public health officials are reminding consumers to wash produce thoroughly and to report prolonged diarrheal illness to their healthcare provider.
