Missouri health officials are investigating dozens of confirmed or probable cases of cyclosporiasis, the intestinal infection that has sickened thousands of people across the country this summer.
As of Sunday, the Missouri Department of Health and Senior Services logged 43 cases of the infection, which causes diarrhea and other digestive symptoms. The department data does not include where in the state cases have been reported.
Missouri has a relatively small number of reported cases compared to Michigan and other states at the center of the outbreak.
Illinois health officials have reported 216 cases of the infection, according to the state's health department. In Michigan, the state with the most reported cases, health officials have logged more than 3,700 cyclospora infections.
Officials expect that number to go up as more people are tested. Because people with diarrhea rarely go to the doctor and even fewer of those people receive the necessary stool sample test, it's likely more people are infected.
Local health departments are following up with patients to get their food and travel history, which could help identify where the parasite came from.
Cyclosporiasis can cause watery diarrhea, nausea and dehydration. Unlike other illnesses caused by food-borne pathogens, fever and vomiting are relatively rare symptoms. Most people recover from the infection without treatment, but antibiotics can clear the infection.
According to the Centers for Disease Control and Prevention, no deaths have been reported due to the current outbreak.
Cyclospora, a parasite that can only be seen through a microscope, is spread through human feces. Past outbreaks have been linked to leafy greens, but officials have not yet found the cause of this year's outbreak.
People can prevent the illness by thoroughly washing produce, cutting off bruised or damaged bits and refrigerating cut fruits and vegetables. Heat kills the parasite, so cooking vegetables can also cut down on risk.
Copyright 2026 St. Louis Public Radio
