Cyclospora – An Elusive Intestinal Parasite Hiding on Raw Produce

Vegetables should be thoroughly washed to remove harmful microorganisms, especially if you plan to eat them raw. Image courtesy of Man vyi.

Thoroughly wash vegetables to remove harmful microorganisms, especially if you plan to eat them raw. Image courtesy of Man vyi.

On July 15, 2013 the Iowa Department of Public Health issued an update on their investigation of a Cyclospora outbreak that began in mid-June.

They report 71 confirmed cases to date (and Nebraska has cases as well).

It’s likely that there are many more people affected, though their infections remain undiagnosed.

The History of Cyclospora

Thirty-five years ago, no one had heard of Cyclospora cayetanensis. Then in 1979, a paper published in the Annals of Tropical Medicine and Parasitology described “another distinct human coccidian, found three times by chance in routine stool examination” All three patients lived in Papua New Guinea, and two of the three had diarrhea.

It will be interesting,” author R. W. Ashford wrote, “to see whether this parasite is commoner than it seems, and whether it has a wider range than Papua New Guinea.” Ashford’s words would prove prophetic over the next three and a half decades.

Cyclospora remained a rarely-encountered exotic parasite for nearly twenty years, while parasitologists tried to determine what sort of organism it was. Ultimately Ashford’s preliminary identification proved correct: Cyclospora is a coccidian, a protozoan parasite. In the human intestine, it invades human cells, multiplies, and produces the immature oocysts seen in laboratory specimens.

Cyclospora cayetanensis finally received its scientific name in 1993, just in time for its dramatic emergence in 1996 as the cause of a large outbreak of gastroenteritis. Hundreds in the United States and Canada fell ill.


The 1996 Cyclospora outbreak helped laboratories hone their identification skills, and helped physicians define the symptoms of the disease. Destruction of intestinal cells results in the most notable symptom – diarrhea – often described as watery and explosive. It may appear to be improving and then relapse, and may last for weeks to months. Other symptoms include nausea, vomiting, abdominal cramps, loss of appetite, and general malaise.

Click to Read Page Two: Cyclosporiasis and Antibiotics

© Copyright 2013 Rosemary Drisdelle, All rights Reserved. Written For: Decoded Science
Decoded Everything is a non-profit corporation, dependent on donations from readers like you. Donate now! Your support keeps the great information coming!

Donation Information

I would like to make a donation in the amount of:


I would like this donation to automatically repeat each month

Tribute Gift

Check here to donate in honor or memory of someone

Donor Information

First Name:
Last Name:
Please do not display my name publicly. I would like to remain anonymous


  1. says

    I think protozoans cause some of the worst illnesses! I hope microbiologists determine what the causes are. Most vegetables (and all meat products) I cook, with the single exception of salad items. But fruits… that’s a different story.

Leave a Reply

Your email address will not be published. Required fields are marked *