The Illinois and Iowa departments of health this week reported that they’re investigating reports of people contracting cyclosporiasis after eating salads at McDonald’s restaurants. Illinois reported 90 cases of the intestinal illness so far and Iowa has discovered 15 cases. Both departments of health report that a portion of the people who suffered from the illness had eaten a salad at a McDonald’s in the days leading to their sickness.

Cyclosporiasis is an intestinal illness caused by the Cyclospora parasite. According to the Iowa Department of Public Health, the parasite is most commonly found in developing countries, but has been increasingly affecting Americans during the summer months. People often contract the illness after eating fresh produce contaminated with the parasite.

However, unlike many other food-borne illnesses, cyclosporiasis can take a week or more before it starts to affect the body. Its symptoms, which include frequent watery diarrhea, weight loss, nausea, and fever, can last from a few days to more than a month if left untreated. Antibiotics designed to address cyclosporiasis can kick it sooner.

The health departments were quick to note in statements this week that they cannot say for sure that McDonald’s salads are to blame for the recent outbreaks. There is, however, a link between the salads at some restaurants in Illinois and Iowa and the illness. They both encouraged people suffering from cyclosporiasis symptoms to contact the health departments to aid them in their investigations.