Cases of people infected by the Cyclospora parasite, believed to have originated from ingesting lettuce in McDonald’s salads, have spread to another four states—Wisconsin, Nebraska, South Dakota, and Minnesota.
The numbers are limited so far, according to health officials, who say each state has two cases, with the exception of Minnesota, which has three, reported USA Today.
The Iowa and Illinois health departments said on Thursday that they were investigating Cyclospora infections linked to salads at McDonald’s restaurants. The Illinois Department of Public Health said it had recorded about 90 cases since mid-May, and the Iowa Department of Public Health said it had recorded 15 cases since late June.
The parasite, Cyclospora cayetanensis, infects the small intestine, typically causing watery diarrhea and frequent, sometimes explosive bowel movements. Other symptoms include loss of appetite, weight loss, stomach pain, and fatigue.
The nonfatal infection is spread by eating or drinking food or water contaminated with feces and not directly from one person to another. People are affected around seven days after ingesting the food. The illness is treated with antibiotics.
McDonald’s said it had voluntarily stopped selling salads at 3,000 of its U.S. restaurants, most of which are in the Midwest, until it could switch to another lettuce blend supplier.
The Cyclospora parasite is what sickened at least 212 people in the Midwest, who ate from contaminated Del Monte vegetable trays in early July. The trays were sold by Kwik Trip in locations across Illinois, Iowa, Indiana, Michigan, Minnesota, and Wisconsin.
Earlier this year, 210 people across 36 states were sickened by E. coli-rained romaine lettuce from Yuma, Arizona, according to the CDC. The outbreak resulted in five deaths, and 96 people hospitalized, 27 of whom developed kidney failure.
Several outbreaks have occurred in the United States in the past several years, especially during the summer months, that have been linked to imported fresh produce including raspberries, basil, snow peas, and lettuce.
Reuters contributed to this report.