DES MOINES, Iowa – Confirmed cases of a rare food-borne illness have doubled in Iowa over four days and increased dramatically in Nebraska, with public health agencies scrambling Friday to figure out the source.
The outbreak of cyclosporiasis has sickened 45 Iowans, the Iowa Department of Public Health said Friday. On Monday the department had identified 22 cases. The increase may be due to more people hearing about it and getting tested, said Dr. Patricia Quinlisk, the state's epidemiologist and medical director for Iowa' public health agency.
"We're not ready to say it's absolutely for sure, but things are pointing more toward a vegetable rather than a fruit but we're still looking at everything," Quinlisk said of the source. She suggests that people wash fruits and vegetables thoroughly to reduce the risk of illness.
In Nebraska, the state had documented 35 cases as of Friday, mostly in Douglas County on the eastern edge bordering Iowa.
The illness is most commonly contracted by eating food or drinking water contaminated with human or animal feces containing the cyclospora parasite. Since the parasite needs several days — sometimes weeks — to become infectious, it is not passed directly from person to person. It typically takes a week to get sick after ingesting the parasite.
Symptoms of cyclosporiasis include watery diarrhea, loss of appetite, weight loss, stomach cramps, nausea, body aches and fatigue. If untreated, it can cause frequent, sometimes explosive, bowel movements that lasts an average of 57 days if untreated.
Most of the 45 Iowa residents became sick in mid to late June and at least one person has been hospitalized. Many people report still being ill with diarrhea and some have seen the symptoms ease but then return. The U.S. Centers for Disease Control and Prevention said relapses are not unusual.
The recommended treatment is a combination of two antibiotics, which shortens the duration of the illness significantly, said Nebraska state epidemiologist Dr. Thomas Safranek. People who have diarrhea should also rest and drink plenty of fluids.
Quinlisk said investigators are trying to determine whether the confirmed illnesses were the result of a batch of contaminated produce and if new batches being delivered are continuing the exposure.
"Right now, it's hard to say but most people coming in now did get sick a while ago not a couple of days ago," she said. "We don't want to say yet whether exposures continue. We don't know for sure."
Safranek said all of Nebraska's cases also involve people who became ill in June, which suggests whatever contaminated food that caused it may have worked its way through the system.
"If we start getting people who have new onset dates here in July that's going to be a cause for concern. There's a specter of hope that it may have passed through the system whatever it was and there's no ongoing risk," he said.
Quinlisk and Safranek believe the illnesses may be traced to a food product distributed primarily to Iowa and Nebraska. Three other states are investigating cases but Quinlisk said no definite link has been established.
The illness is rare in Iowa with typically just one to two cases reported a year, usually involving people who acquired the illness while traveling, Quinlisk said. The illness also is rare in Nebraska with no cases reported in the last four years and only one case in 2007 and one in 2008.
Iowa's Linn County has largest concentration of cases with 21. Fayette, Polk, and O'Brien counties each had three cases, and Dallas, Mills, Webster, and Des Moines counties each had two cases confirmed. Another seven counties each reported one confirmed case.
Data from the CDC indicates it is not a widely occurring illness nationally. In 2011, the most recent year for which national data is available, the agency documented 151 cases. Outbreaks in recent years have been traced to blackberries, raspberries, strawberries, basil, arugula, vegetable-based salads, pasta salad, tuna salad, green beans, peas, and fruit salad.