Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 35-09: Coccidiosis (Cryptosporidiosis, Isosporiasis, Cyclosporiasis, Sarcocystosis) & Microsporidiosis + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis +++ IN IMMUNOCOMPETENT PATIENTS ++ Self-limited watery diarrhea lasting 2–3 weeks Abdominal cramps, anorexia, malaise, weight loss Fever is unusual +++ IN IMMUNOCOMPROMISED PATIENTS ++ Severe and chronic diarrhea Extraintestinal disease has been reported rarely +++ General Considerations ++ Causes of coccidiosis Cryptosporidium spp, particularly C parvum and C hominis Isospora belli Cyclospora cayetanensis Sarcocystis species These organisms cause endemic childhood gastroenteritis (particularly in malnourished children in developing countries) Infection is transmitted from person to person or by contaminated drinking or swimming water or food Ingested oocysts release sporozoites that invade and multiply in enterocytes, primarily in the small bowel Coccidian oocysts and microsporidian cysts can remain viable in the environment for years I belli appears to infect only humans Incubation period for I belli is about 1 week +++ Demographics ++ The infection occurs worldwide, particularly in the tropics and in regions where hygiene is poor Clustering occurs in households, day care centers, and among sexual partners + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs +++ IN IMMUNOCOMPETENT PERSONS ++ Causes a self-limited watery diarrhea lasting 2–3 weeks Abdominal cramps, anorexia, malaise, and weight loss Fever is unusual Chronic symptoms may persist for months +++ IN IMMUNOCOMPROMISED PATIENTS ++ Causes severe and chronic diarrhea Extraintestinal disease has been reported rarely +++ 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 + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests ++ Diagnosis is made by examination of stool wet mounts or after modified acid-fast staining, in which the organism is clearly distinguishable from other parasites Other stains also show the organism Sensitivity of stool evaluation is not high because shedding of oocysts may be intermittent; multiple samples should be examined +++ Diagnostic Procedures ++ Organism may also be identified in duodenal aspiration or small bowel biopsy specimens + Treatment Download Section PDF Listen +++ +++ Medications ++ Most infections in immunocompetent persons do not require treatment Trimethoprim-sulfamethoxazole 160 mg/800 mg two to four times daily for 10 days Higher doses for patients with AIDS An alternative therapy is pyrimethamine (75 mg orally in four divided doses) with folinic acid (10–25 mg/day orally) Maintenance therapy prevents relapse in persons with persistent immunosuppression Low-dose trimethoprim-sulfamethoxazole (160 mg/800 mg daily or three times per week) Fansidar (1 tablet weekly) +++ Therapeutic Procedures ++ Supportive treatment for severe or chronic diarrhea includes Fluid and electrolyte replacement Parenteral nutrition + Outcome Download Section PDF Listen +++ +++ Complications ++ Marked dehydration, malnutrition, and hemorrhagic colitis in immunocompromised patients +++ Prevention ++ Water purification is important for control of these infections Chlorine disinfection is not effective against cryptosporidial oocysts, so other purification measures are needed Immunocompromised patients should Boil or filter drinking water Consider avoiding lakes and swimming pools Routine precautions (handwashing, gloves, disinfection) should prevent institutional patient-to-patient spread +++ When to Refer ++ Persistent symptoms despite therapy, particularly in immunocompromised patients +++ When to Admit ++ Profuse diarrhea causing hypotension or electrolyte imbalance + References Download Section PDF Listen +++ + +Almeria S et al. Cyclospora cayetanensis and cyclosporiasis: an update. Microorganisms. 2019 Sep 4;7(9):E317. [PubMed: 31487898] + +Giangaspero A et al. Human cyclosporiasis. Lancet Infect Dis. 2019 Jul;19(7):e226–36. [PubMed: 30885589] + +Hemphill A et al. Comparative pathobiology of the intestinal protozoan parasites Giardia lamblia, Entamoeba histolytica, and Cryptosporidium parvum. Pathogens. 2019 Jul 29;8(3):E116. [PubMed: 31362451]