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 ++ 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 + Clinical Findings Download Section PDF Listen +++ +++ 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 + Diagnosis Download Section PDF Listen +++ +++ 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 + Treatment Download Section PDF Listen +++ +++ 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 + Outcome Download Section PDF Listen +++ +++ 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 + 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]