Parasite Infections Rise To More Than 200 In IL, 18 Hospitalized

Lettuce or salad greens could be a possible source of the parasite infecting people across the country, health officials said.

By Emily Rosca, Patch Staff

Jul 14, 2026 10:40 am CDT | Updated Jul 14, 2026 10:57 am CDT

Health officials have not identified a specific produce item, grower, supplier, restaurant, grocery chain or Illinois location tied to cyclosporiasis, the diarrhea-causing parasite. (CDC via AP)

Cases of cyclosporiasis, the diarrhea-causing parasite infecting people across the country, continue climbing in Illinois, according to reports.

While the Centers for Disease Control and Prevention only shows 31-80 cases in Illinois, the IDPH confirmed 216 cases statewide, including 95 acquired domestically and 96 among those who traveled outside the United States.

There have been 18 hospitalizations in Illinois so far, according to the report.

Last week, state health officials said about 150 were sickened by the intestinal infection, Patch reported.

Cyclosporiasis is caused by the microscopic parasite cyclospora cayetanensis and can lead to watery diarrhea, stomach cramps, nausea, fatigue and loss of appetite. Symptoms typically begin about a week after exposure but can appear anywhere from two days to two weeks or longer after infection, according to the IDPH.

The parasite can spread through food or water contaminated with the parasite, and person-to-person transmission generally does not happen, health officials said. Previous U.S. outbreaks have been linked to fresh produce, including raspberries, basil, cilantro, snow peas and lettuce.

Health officials have not identified a specific produce item, grower, supplier, restaurant, grocery chain or Illinois location tied to the illnesses. The CDC said there is currently no evidence of a single, multi-state cyclospora outbreak linking all cases. Instead, federal, state and local public health officials are investigating several clusters of cases in more than one state.

Lettuce or salad greens could be a possible source, Michigan health officials said Monday. The state is reporting the most cyclosporiasis cases in the country.

The CDC has reported an average of about 2,800 cases per year nationwide, but 2026 is "on track to be the biggest year on record," according to a report from the New York Times. The organization considers May 1 through Aug. 31 the annual cyclosporiasis season since case counts typically rise in the spring and summer.

The best way to prevent infection with a parasite is to avoid food or water that may have been contaminated. Officials recommend properly preparing fruits and vegetables by thoroughly washing them before cutting, eating and cooking.