According to an initial investigation from the Illinois Department of Public Health, about one-fourth of cases in the state reported eating salads from McDonald's before getting ill.
"Although a link has been made to salads sold in McDonald's restaurants in some Illinois cases, public health officials continue to investigate other sources," IDPH Director Nirav D. Shah, said in a statement. "If you ate a salad from McDonald's since mid-May and developed diarrhea and fatigue, contact a health care provider about testing and treatment."
Symptoms of Cyclospora infection include loss of weight and appetite, frequent watery diarrhea, cramping, bloating and increased gas, a low-grade fever, fatigue and nausea. Vomiting is less common, but could still be a symptom of infection.
Cyclospora is not spread directly from person to person, but people get infected by consuming food or water contaminated with feces that contain the parasite, according to the IDPH. It is the same parasite that has been linked to Del Monte vegetables, according to the U.S. Food and Drug Administration.
"Out of an abundance of caution, we decided to voluntarily stop selling salads at impacted restaurants until we can switch to another lettuce blend supplier," McDonald's told People in a statement. "We are in the process of removing existing salad blend from identified restaurants and distribution centers – which includes approximately 3,000 of our U.S. restaurants primarily located in the Midwest.
“McDonald’s is committed to the highest standards of food safety and quality control,” the burger chain added. “We are closely monitoring this situation and cooperating with state and federal public health authorities as they further investigate.”