BLOOMINGTON — An unusually severe foodborne illness outbreak continues to grow, with 519 cases of cyclosporiasis statewide, including about 80 in Central Illinois.
But the rising numbers may not mean recent exposure to the source of the illness, whose symptoms include severe diarrhea that can last as long as a month.
"The time it takes for a person to feel ill can be up to two weeks, which is much longer than is seen with other foodborne illnesses," Lisa Slater, communications specialist with the McLean County Health Department, explained Friday.
The longer incubation period has made it challenging for public health investigators to pinpoint the source of each illness.
Illinois Department of Public Health (IDPH) said that 206 of the 519 Illinoisans who have gotten sick with cyclosporiasis since mid-May reported eating salads at McDonald's restaurants. Another 150 people have been linked to a private event at the Evanston Golf Club.
Three people have become sick with cyclosporiasis in Macon County. None are associated with McDonald's and one of the people had recently traveled out of the country, said Carol Carlton, Macon County Health Department clinical nursing services director.
McDonald's earlier this month removed its lettuce blends from 3,000 restaurants, primarily in the Midwest, and replaced the lettuce with blends from a different supplier.
Cyclosporiasis, an intestinal illness caused by the microscopic Cyclospora parasite, results in frequent and sometimes explosive bowel movements; loss of appetite and weight; cramping, bloating and gas; nausea; fatigue and low-grade fever.
The infection may be treated with antibiotics, so anyone who experiences symptoms should contact their health care provider. Untreated, the illness may last from a few days to a month.
People become infected by consuming food or water contaminated with feces that contains the parasite. Cyclospora is not transmitted person to person.
"We typically see only one or two internationally acquired cases of cyclosporiasis a year so to have a domestic outbreak is unusual," Slater said.
As of Friday, McLean County had 27 confirmed cases of cyclosporasis and one of those people required hospitalization, Slater said. "An association has been made with salads from a fast-food chain," she said.
Tazewell County has had 28 suspected or confirmed cases so far, said Angie Phillips, Tazewell County Health Department clinical services director.
In Piatt County, there have been nine confirmed cases, with three in DeWitt County, said David Remmert, administrator of the DeWitt-Piatt Bi-County Health Department. Ten of the 12 cases have been traced to McDonald's salads and two have not been linked to any one source, Remmert said.
Ford County has had three confirmed cases and two ate McDonald's salads, said Diane Tavenner, Ford County Health Department registered nurse.
Woodford and Logan counties each have had one confirmed case, and Livingston County has had one suspected case. The Logan County resident had eaten a McDonald's salad outside of the county, according to Mary Anderson, communicable disease investigator.
People may reduce their risk by washing hands with soap and water before and after handling food; washing cutting boards, dishes, utensils and counter tops with soap and hot water after food prep; washing fruits and vegetables before eating, cutting or cooking; and refrigerating cut, peeled or cooked fruits and vegetables within two hours.
Contact Paul Swiech at (309) 820-3275. Follow him on Twitter: @pg_swiech