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.

History

• Fever
  • Low-grade fever is common.
• Clinical prodrome
  • Acute onset of diarrhea is typical, but a flulike prodrome may occur.
• Nature of the diarrhea
  • Profuse, nonbloody, watery diarrhea that may be foul smelling
  • Can alternate with constipation
• Other symptoms experienced:
  • Abdominal cramping
  • Fatigue
  • Anorexia
  • Flatulence
  • Vomiting
• Foods that have been consumed in the past 2 weeks
  • Illness has been attributed to contaminated raspberries, water, mesclun, salad mix, cilantro, and basil.

Physical Exam

Dehydration

• Due to profuse diarrhea
• Signs of dehydration (tachycardia, dry mucous membranes, sunken eyes, poor skin turgor, and weight loss) may be present.

Differential Diagnosis

• Cryptosporidium
  • Outbreaks are associated with contaminated water sources (municipal pools).
  • Person-to-person transmission may occur.
  • Clinically indistinguishable from Cyclospora
• Cystoisospora belli
  • Outbreaks are associated with food and water.
  • Clinically indistinguishable from Cyclospora, although fever may be more common
• Microsporidia
  • Outbreaks are associated with contaminated water sources.
  • Chronic diarrhea occurs in immunocompromised patients, especially HIV patients.
  • Fever is uncommon.
• Giardia lamblia
  • Community epidemics are associated primarily with contaminated water sources.
  • Person-to-person transmission may occur and has led to outbreaks in day care centers.
  • Clinical presentation may vary from occasional acute watery diarrhea to a severe, protracted diarrheal illness.
• Viral gastroenteritis
  • Rotavirus
  • Adenovirus
• Bacterial gastroenteritis
  • Clostridium difficile
  • Vibrio cholerae and non-cholerae Vibrio species
  • Escherichia coli (especially toxin-producing strains)
  • Shigella species
  • Salmonella species
  • Yersinia enterocolitica
  • Campylobacter species

Diagnostic Tests and Interpretation

Medication (Drugs)

• Immunocompetent patient: trimethoprim-sulfamethoxazole (5 mg/kg) IV/PO twice a day for 7 to 10 days
• HIV patient: trimethoprim-sulfamethoxazole 3 times a day for 10 days and then prophylactic dosing 3 times per week to prevent relapse
• Ciprofloxacin or nitazoxanide for 7 days may be alternatives in patients with sulfa allergy.
• Based on severity of dehydration, treatment with IV fluids may be indicated.

Inpatient Consideratons

Moderate to severe dehydration should warrant admission.

Follow-Up Recommendations

Prognosis

• Most cases are self-limited.
• Diarrhea may last up to 3 months in untreated patients who acquired the parasite in a foreign country where Cyclospora is endemic.
• In U.S. outbreaks, the average duration of diarrhea ranged from 10 to 24 days.
• Relapses may occur in untreated patients.
• Patients with HIV have more severe and prolonged diarrhea, which may recur.

Complications

• Dehydration and weight loss are the most common complications.
  • Severe, prolonged diarrhea may lead to dehydration.
  • Malabsorption of d-xylose and excretion of fecal fat occurs, leading to weight loss.
• May cause ascending biliary tract disease in AIDS patients
• Rare associated complications
  • Guillain-Barré syndrome
  • Reactive arthritis

ICD-9

007.5 Cyclosporiasis

ICD-10

A07.4 Cyclosporiasis

SNOMED

240372001 Cyclosporiasis (disorder)