Iowa and Nebraska public health officials report a prepackaged salad mix is the source of the intestinal illness cyclospora, which has sickened more than 200 people in the two Midwestern states.

The Iowa Department of Public Health reports that at least 80 percent of the 145 people infected with the stomach illness in the state were exposed to the same prepackaged salad mix of iceberg and romaine lettuce with carrots and red cabbage. Nebraska's department of health reports that the 78 cyclospora patients in the state were also exposed to salad mix.

The two health departments have shared the results of their study with the Centers for Disease Control and Prevention (CDC) and the investigation of the cyclospora outbreak, which has sickened at least 378 people across 15 states and New York City, is still underway.

The manufacturer or brand of the salad mix has not been disclosed but Iowa public health officials report the mix is no longer in the state's food supply chain, nor was any of the produce contained in the prepackaged mix grown in Iowa.

"Onset dates of the illness suggest the ill people had eaten the contaminated food in mid-June. This is a very good indication the food which was the source of the outbreak has already been consumed or discarded, since fresh vegetables have a limited shelf life," the Iowa Department of Public Health said in a statement.

Cyclospora is a lengthy intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

People may become infected with cyclospora after consuming food or water contaminated with the parasite, according to the CDC. The Food and Drug Administration (FDA) reports the parasite is unlikely to be transmitted from one person to another, which suggests that those infected consumed a contaminated food or beverage.

Iowa has reported 143 cases of cyclospora, followed by Texas (101), Nebraska (78), Florida (25), Wisconsin (9) and New York City (5). Illinois, Minnesota, Missouri, Kansas, Arkansas, Georgia, Ohio, Connecticut, New Jersey and New York state have each reported four or fewer cases.

Twenty-one people have been hospitalized across the country as a result of cyclospora infection, the CDC reports.

It typically takes about one week between being infected with cyclospora and the first signs of symptoms. The parasite infects the small intestine and "usually causes watery diarrhea, with frequent, sometimes explosive, bowel movements," according to the FDA.

Cyclospora infection is not thought to be life-threatening, though a spokesperson for the Nebraska Department of Health and Human Services said some infected residents dropped 25 pounds while fighting the illness.

Other symptoms include loss of appetite, weight loss, stomach cramping or bloating, flatulence, fatigue and in some cases vomiting, headache, fever and other flu-like symptoms are observed. It is typical for the infected to observe their symptoms going away and later relapsing. Some people infected with the parasite do not show any symptoms.

If untreated, a cyclospora infection can last as long as 57 days, according to Ann Garvey, deputy state epidemiologist for the Iowa Department of Public Health.