Description

Cyclospora cayetanensis, a coccidian protozoan, causes a diarrheal illness first described in humans in 1979.

General Prevention

Fresh produce, especially raspberries, cilantro, and salad mixes, should be washed thoroughly before being eaten, although this still may not entirely eliminate the risk of transmission.

Epidemiology

• Worldwide distribution, with areas of endemic infection (Nepal, Peru, Haiti, Guatemala, Indonesia)
• People living in endemic areas have a shorter illness or may be asymptomatic carriers.
• Cyclospora can be an opportunistic infection in human immunodeficiency virus patients.
• In the United States, infection occurs primarily in spring and summer.
• In the United States and Canada, cases are associated with consumption of imported fresh produce.

Pathophysiology

• Infected patients excrete noninfectious unsporulated oocysts in their stool.
• Sporulation then occurs days to weeks after release into the environment.
• Ingestion of sporulated oocysts occurs and sporozoites are released that invade the intestinal epithelial cells.
• Sporozoites develop into trophozoites, which undergo schizogony and form merozoites.
• Merozoites may develop into macro- or microgametes, which become fertilized, resulting in oocysts.
• Entire life cycle is completed in the host.
• Incubation period is between 2 and 14 days, with an average of 7 days.

Etiology

• Outbreaks have been associated with the consumption of raspberries, mesclun (young salad greens), salad mixes, cilantro, and basil.
• Infection occurs through the consumption of contaminated food and water.
• Transmission does not occur through person-to-person spread.