The departments of public health in IL and Iowa both announced Thursday that an investigation into the outbreak is underway.
"Anyone who ate these salads since the middle of June and who developed diarrhea, especially watery diarrhea and fatigue, should see their health care provider and get tested for Cyclospora to ensure an accurate diagnosis and appropriate treatment", said Patricia Quinlisk, Iowa " s public health medical Director and epidemiologist.
The victims in IL became ill in mid-May and have been diagnosed with cyclosporiasis, an intestinal illness caused by microscopic parasites.
McDonald's is "fully cooperating" with state health departments, the Centers for Disease Control and Prevention, and the Food and Drug Administration investigation, IDPH said. McDonald's has voluntarily stopped selling salads at affected restaurants across 14 states and the CDC reports that 61 people across seven states have gotten sick.
It said that it had voluntarily stopped selling salads at the approximately 3,000 affected USA restaurants until it could switch to another lettuce blend supplier.
Cyclospora can cause stomach cramps, nausea and flu-like symptoms a week or more after the consumption of food or liquid contaminated with the parasite.
Lincoln and Omaha locations are not impacted by a possible outbreak linked to McDonald's salads.
In Illinois, public health officials have counted 90 cases of cyclospora since mid-May.
The fast-food company also said it is removing its existing salad blend from about 3,000 of its outlets, majority in the Midwest.
Health officials in both IL and Iowa said that people who experienced similar symptoms after eating at McDonald's should contact a doctor for testing and possible treatment.
It added that anyone who developed diarrhea and fatigue after consuming a McDonald's salad should contact a health official immediately. - If not treated, the illness may last from a few days to a month or longer.
"McDonald's is committed to the highest standards of food safety and quality control".