DESCRIPTION

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

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.

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.
• Avoid consumption of waste water and, in endemic areas, avoid consumption of tap water.

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.