Everyone who became ill in Iowa and about a quarter of those who became sick in IL said they had eaten McDonald's salads in the days before symptoms appeared, according to the states' health departments. Iowa has identified 15 people who ate McDonald's salads in late June to early July prior to getting ill and IL has seen 90 cases of cyclosporiasis with a quarter of the infected people having eaten a McDonald's salad before getting ill.
In Illinois, public health officials have counted 90 cases of cyclospora since mid-May.
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. About one quarter of the cases have been linked to McDonald's salads.
The Iowa Public Health Department said it identified 15 cases linked to the same illness and parasite who ate there in June and July.
People can become infected by consuming food or water contaminated with feces (stool) that contains the parasite. "This summer there have been several clusters of Cyclospora illness associated with various foods that are commercially available", a statement from the Iowa Department of Public Health said.
Cyclospora is a parasite more commonly found in developing countries. Officials say McDonald's will re-supply restaurants with salads from other suppliers. Left untreated, the illness "may last for a few days to a month or longer", according to the Centers for Disease Control and Prevention.
"McDonald's is committed to the highest standards of food safety and quality control".
McDonald's said "out of an abundance of caution" it is in the process of removing salads from some restaurants and distribution centres and will resupply restaurants with salads from other suppliers, USA Today reported.
McDonald's said in an email it has been in contact with public health authorities from both states about an increase in Cyclospora infections.