More than 100 people in the Midwest have been infected by an intestinal parasite in recent weeks that has been tied to the consumption of salads at McDonald’s, health experts announced this week.

Public health officials in Illinois and Iowa have reported a spike in cases of cyclosporiasis, with at least 15 infections in Iowa and 90 others in Illinois. Everyone who became ill in Iowa and about a quarter of those who became sick in Illinois said they had eaten McDonald’s salads in the days before symptoms appeared, according to the states’ health departments.

In a public statement released Friday, McDonald’s said that “out of an abundance of caution,” the restaurant will temporarily stop selling salads at about 3,000 restaurants in the Midwest. The company is working to remove the lettuce from those locations and distribution centers and will switch to another supplier at those locations. At least one of those restaurants is in Wisconsin, though officials did not specify the exact location.

“McDonald’s is committed to the highest standards of food safety and quality control,” the company said in a statement. “We are closely monitoring this situation and cooperating with state and federal public health authorities as they further investigate.”

Cyclosporiasis is caused by a microscopic parasite found in food or water contaminated with feces. The infection, which is rarely fatal, can cause severe nausea, fatigue and diarrhea with symptoms lasting a week or longer, health officials say.  Symptoms typically appear within a few days of infection.

The cases in Illinois first appeared in mid-May, while the illnesses in Iowa were more recent, surfacing in late June and early July.

Meanwhile, health officials continue to investigate state another outbreak of 225 cases of cyclosporiasis in Wisconsin and five other states which have been tied to Fresh Del Monte Produce vegetable trays. The Centers for Disease Control and Prevention has investigated more than 2,000 cases of cyclosporiasis since 2000.