Health
Illinois Confirms 194 Probable Cases of Cyclosporiasis as Parasitic Infection Spreads
Eunice Alpasan | July 13, 2026, 6:00 pm
This undated photo taken through a microscope provided by the CDC shows Cyclospora cayetanensis oocysts found in a fresh stool sample which had been prepared with a formalin solution and stained with safranin. (CDC via AP)
An outbreak of a diarrhea-causing parasitic infection has hit more than half of U.S. states, including Illinois.
The state has seen 194 confirmed and probable cases of cyclosporiasis as of Monday, according to the Illinois Department of Public Health. In Chicago, there are 47 confirmed and probable cases among residents, according to the Chicago Department of Public Health on Monday. Of that number, 23 have not traveled internationally, making it more likely they acquired the illness locally, according medical director Dr. Janna Kerins
“This is a higher than typical number than we have seen in previous years,” Kerins said.
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Cyclosporiasis is a gastrointestinal disease caused by the parasite cyclospora, which can commonly cause watery diarrhea “with frequent and sometimes explosive bowel movements,” according to the U.S. Centers for Disease Control and Prevention.
The disease can be spread by consuming contaminated food or water.
While foodborne outbreaks of cyclosporiasis in the U.S. have previously been linked to fresh produce such as raspberries, basil, cilantro, snow peas and lettuce, there isn’t a specific food that can be traced to the current uptick in cases we’re seeing in Chicago, according to health officials
“Really nothing has jumped out yet, unfortunately,” Kerins said. “We don’t have any kind of common food items, common restaurants that we have seen that would explain why we’re having this increase in cases.”
Cyclosporiasis is not usually life-threatening, but the illness can last from a few days to over a month, according to health officials. Individuals who are very young, those with a weakened immune systems or who have a chronic underlying disease, and older adults are at higher risk for severe illness
The number of cases is likely underreported because most of the cases reported by public health agencies are from people who have sought care and been tested Cyclosporiasis can be treated with an antibiotic, but in most healthy people, it can go away on its own and may not require treatment, Kerins added
In Illinois, 16 hospitalizations due to a confirmed or probable case of cyclosporiasis have been reported, according to the state’s health department. No deaths have been reported.
“IDPH is seeing a higher-than-average number of reported cases of cyclosporiasis, consistent with what is being seen in several other states,” an IDPH statement said. “At this point, no singleno evidence of a large outbreak accounting for all or most of these cases.”
The state’s public health department is working with the CDC and other public health partners to look for trends, according to an IDPH spokesperson
Outbreaks of cyclosporiasis tend to occur most often in the late spring and summer
Health officials recommend practicing the following food handling guidelines to protect yourself:
- Wash your hands before and after handling and preparing produce.
- If you are going to eat fresh produce, it is best to wash it under running water, even if you plan to peel it.
- If it’s firm enough, scrub the produce with a clean produce brush.
- When preparing a head of lettuce, remove the outer layers and rub the leaves as you wash. Similarly, wash and rub the leaves for produce like cilantro or basil.
- If any produce has damaged or bruised areas, remove those areas before eating.
- Refrigerate fruits or vegetables.
- Clean surfaces and utensils after preparing produce.
“A lot of what we can do, unfortunately, is only to reduce the numbers of the parasite as opposed to eliminating it directly,” Kerins said. “It can definitely help to wash produce, so you’re trying to lessen the risk, but it is not foolproof.”
To actually kill the parasite, cook fruits and vegetables to at least 158 degrees Fahrenheit
Nationwide, 31 states have reported cases of cyclosporiasis, according to the CDC, which last updated data Thursday. Michigan has been the hardest hit as the number of people who’ve contracted the parasite has now reached more than 2,600, growing by nearly 1,000 cases over the weekend, the Detroit Free Press reported Monday
Last summer, the CDC quietly scaled back a federal-state partnership that monitors for foodborne illnesses known as FoodNet by no longer requiring monitoring for several pathogens, including cyclospora, and instead, requiring monitoring for just two pathogens: salmonella and Shiga toxin-producing E. coli, NBC News reported.
IDPH did not directly respond to a request for comment on whether changes in federal policy and funding has impacted its ability to track foodborne illness in the state
The Associated Press contributed to this report
Contact Eunice Alpasan: [email protected]
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Illinois Department of Public Health
Chicago Department of Public Health
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