Cyclosporiasis

Essentials of Diagnosis

IN IMMUNOCOMPETENT PATIENTS

• Mild to severe diarrhea

• Abdominal cramps, nausea, fatigue, anorexia, fever

IN IMMUNOCOMPROMISED PATIENTS

• Infection can be severe and prolonged

• Chronic fulminant diarrhea

• Weight loss

General Considerations

• Causes of coccidiosis

  • Cryptosporidium spp (eg, C parvum and C hominis)

  • Isospora belli

  • Cyclospora cayetanensis

  • Sarcocystis species

• The infectious agents are oocysts (spores) transmitted by contaminated water or food

• Cyclospora

  • Infects only humans

  • Requires time (about 7 days) outside the host to sporulate and become infectious

• Outbreaks in the United States have been attributed to imported fresh produce

• Infection causes

  • Endemic childhood gastroenteritis (especially in malnourished children in developing countries)

  • Traveler's diarrhea

  • Institutional and community outbreaks of diarrhea

  • Acute and chronic diarrhea in immunosuppressed patients, in particular those with AIDS

Demographics

• Occurs worldwide, particularly in the tropics and in regions where hygiene is poor

• Clustering occurs in households, day care centers, and among sexual partners

Symptoms and Signs

• The incubation period is 1–11 days

• Infections can be asymptomatic

• Watery diarrhea

• Abdominal cramps, nausea, fatigue, anorexia, fever (in 25% of cases)

• Symptoms typically last for 2 weeks or longer and may persist for months without therapy

• Relapses of diarrhea are common

• Diarrhea may be preceded by a flu-like prodrome and followed by persistent fatigue

• In immunocompromised patients, infection is typically more severe and prolonged, with chronic fulminant watery diarrhea and weight loss

Differential Diagnosis

• C parvum, I belli, S bovihominis, and S suihominis

• Giardiasis

• Viral gastroenteritis, eg, rotavirus

• Other traveler's diarrhea, eg, Escherichia coli

• Cholera

• Other causes of diarrhea in AIDS, eg, cytomegalovirus colitis

Laboratory Tests

• Diagnosis is made by examination of stool wet mounts or after modified acid-fast staining

• Multiple specimens may need to be examined to make a diagnosis; concentration of specimens improves sensitivity

• The organism can also be identified in small bowel aspirates or biopsy specimens

• Molecular assays with high sensitivity and specificity, including multi-pathogen panels, are available

Medications

• Trimethoprim-sulfamethoxazole (TMP-SMZ)

  • 160/800 mg two to four times daily for 10 days

  • Higher doses may be needed for patients with AIDS

• Pyrimethamine

  • An alternative therapy

  • Dosage is 75 mg orally in four divided doses with folinic acid (10–25 mg/day orally)

• For patients with AIDS, long-term maintenance (160 mg/800 mg three times weekly) helps prevent relapse

• For patients intolerant of TMP-SMZ, ciprofloxacin (500 mg orally twice daily for 7 days) showed efficacy, but with less ability to clear the organism than TMP-SMZ

Follow-Up

• Parasitologic clearance may take several months even in immunocompetent patients

• Passage of organisms continues for months to indefinitely in immunodeficient persons

Prevention

• Water purification

• Immunocompromised patients should boil or filter drinking water and should consider avoidance of lakes and swimming pools

• Routine precautions (handwashing, gloves, disinfection) should prevent institutional patient-to-patient spread

When to Refer

• Refer to an infectious disease specialist or gastroenterologist if diarrhea persists despite antibiotic therapy, particularly in immunocompromised patients

• Refer for secretory or malabsorption diarrhea

• Refer for progressive weight loss

When to Admit

• Profuse diarrhea causing hypotension or electrolyte imbalance