Originally reported as a novel pathogen of probable coccidian nature in the 1980s[1] and described in the early 1990s,[1] it was virtually unknown in developed countries until awareness increased due to several outbreaks linked with fecally contaminated imported produce.

[2] As originally recognized by Markus & Frean (1993),[3] the first published report of Cyclospora cayetanensis in humans appears to be by Ashford (1979), who found unidentified Isospora-like coccidia in the feces of three individuals in Papua, New Guinea.

Eventually, Ortega et al. (1992) published an abstract reporting that they had sporulated and excysted the oocysts, resulting in placement of the parasite in the genus Cyclospora.

[4] Thus, the correct name for this parasite is Cyclospora cayetanensis Ortega, Gilman, & Sterling, 1994, and the etymology of the nomen triviale is derived from Cayetano Heredia University in Lima, Peru.

During this two-year period when C. cayetanensis was a nomen nudum, anyone wishing to publish a complete morphologic description and change the name would have been free to do so.

In terms of morphology, It has spherical oocysts that are between 7.5 and 10 μm in diameter that also have a 50-nm-thick wall with an outer thread-like coat that has been called a wrinkle by some researchers.

After fertilization has occurred via male microgamete fusion with female macrogamont, the zygote matures into an oocyst and ruptures the host cell, from which point it is passed with the stool.

This differentiates C. cayetanensis from Cryptosporidium parvum—a closely related organism that causes a similar disease—since C. parvum oocysts are immediately infectious upon release from the host.

[6] C. cayetanensis causes gastroenteritis, with the extent of the illness varying based on age, condition of the host, and size of the infectious dose.

Typically, patients with a persistent watery diarrhea lasting over several days may be suspected of harboring the disease, especially if they have traveled to a region where the protozoan is endemic.

There is presence of moderate to severe dehydration, compensatory tachycardia, systolic blood pressure (SBP<90 mmHg) and decreased skin turgor may occur.

Infections in endemic regions tend to show a marked seasonality that is poorly understood, whereas North American outbreaks occur most frequently in late spring and summer, correlating with increased import of produce from the tropics.

Since detection is so hard, one negative result should not discount the possibility of C. cayetanensis: tests involving fresh stool samples over the next few days should also be considered.

Additionally, TMP-SMX can be excreted in breast milk, which is compatible in healthy, full-term newborns, but should be avoided in premature, ill, stressed, or jaundiced infants.

[1] The odds of becoming infected with Cyclospora, and many other foodborne pathogens, can be greatly diminished by thoroughly washing fruits and vegetables in clean water prior to consumption.

The table provides information about 31 reported foodborne outbreaks of cyclosporiasis that occurred in the United States during 2000–2014; the total case count was 1,562.

[citation needed] Summary of U.S. foodborne outbreaks of cyclosporiasis, 2000–2014 [18] * The entries in the first three columns refer to the known or likely year(s), month(s), and jurisdiction(s) in which the exposure(s) to Cyclospora occurred.

For the purposes of this table, the exposure month(s) and case counts are limited to those explicitly linked in the investigations to the food item specified in the last column.

For the purposes of this table, the exposure months and the case count for the outbreak in Texas are limited to those explicitly linked in the investigations to the food item specified in the last column.

[22] On August 3, 2013, CNN reported that the outbreak was traced to packaged salad served at Olive Garden and Red Lobster restaurants that was manufactured by Taylor Farms de Mexico.

The number of affected states remained at 19, but the CDC said that not all cases were confirmed to be linked to an outbreak in Iowa and Nebraska traced to a contaminated salad mix from Mexico.

The FDA said it found no food safety violations at the Taylor Farms de Mexico salad plant that was linked to some of the illnesses.

[26] Health officials said more than a dozen cases of cyclosporiasis had been confirmed in North Texas' four major counties and that the source was likely contaminated food.

The Texas Department of State Health Services said Wednesday the parasite was found in Dallas, Tarrant, Collin and Denton counties and that the origin may have been linked to a fresh produce item.

[28] McDonald's stopped selling salads[28] supplied by Fresh Express at some 3,000 locations across the country mostly in the Midwest United States due to a multistate parasite outbreak that had sickened 551 people caused by Cyclospora.

[29] In June 2020, the CDC and other regulatory bodies began investigating an outbreak of Cyclosporiasis in the Midwestern United States linked to bagged salad mix.