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 ++ Watery diarrhea Abdominal pain and cramps Nausea and vomiting Fever Mild illnesses and asymptomatic infection may also be common +++ IN IMMUNOCOMPROMISED PATIENTS ++ Chronic diarrhea with frequent foul smelling stools Malabsorption, weight loss Severe, life-threatening watery diarrhea may be seen Extraintestinal disease +++ General Considerations ++ Causes of coccidiosis Cryptosporidium spp (eg, C parvum and C hominis) Isospora belli Cyclospora cayetanensis Sarcocystis species Oocysts (coccidiosis) or spores (microsporidiosis) are transmitted From person to person 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 Coccidia and microsporidians are generally missed on routine evaluations of stool for ova and parasites because special staining techniques are required for identification Leading cause of recreational water-associated outbreaks of gastroenteritis +++ Demographics ++ These infections occur worldwide, particularly in the tropics and in regions where hygiene is poor In developing countries, infection seen primarily in children younger than 5 years In developed countries, most patients are adults Clustering occurs in households, day care centers, and among sexual partners Outbreaks are of particular concern, as exemplified by the 1993 epidemic in Milwaukee in which 400,000 persons became ill + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs +++ IN IMMUNOCOMPETENT PATIENTS ++ Incubation period appears to be 1–14 days Symptoms resolve rapidly, but can persist for 2 weeks or more Diarrhea is usually watery, with accompanying abdominal pain and cramps, nausea, vomiting, and fever Relapses may follow initial resolution of symptoms Mild illnesses and asymptomatic infection are also common +++ IN IMMUNODEFICIENT PATIENTS ++ Chronic diarrhea with frequent foul smelling stools Malabsorption Weight loss Severe, life-threatening watery diarrhea may be seen Also causes extraintestinal disease, including Pulmonary infiltrates with dyspnea Biliary tract infection with sclerosing cholangitis and AIDS cholangiopathy +++ Differential Diagnosis ++ Infection with I belli, C cayetanensis, and S bovihominis Giardiasis Viral gastroenteritis, eg, rotavirus Other traveler's diarrhea, eg, Escherichia coli Cholera Other cause of diarrhea in AIDS, eg, cytomegalovirus colitis + Diagnosis Download Section PDF Listen +++ ++ Typically, stool is without blood or leukocytes Diagnosis is made by detecting the organism in stool using a modified acid-fast stain This technique is relatively insensitive Multiple specimens should be evaluated before ruling out the diagnosis Routine evaluation for ova and parasites typically does not include a modified acid-fast stain, so this must be specifically requested in many laboratories Various antigen detection methods, including immunofluorescence microscopy, ELISA, and immunochromatography Offer improved sensitivity and specificity, both over 90% with available assays These methods may now be considered the optimal means of diagnosis Molecular diagnostic panels that recognize Cryptosporidium and other enteropathogens in stool are available but expensive + Treatment Download Section PDF Listen +++ ++ No agent is clearly effective Modest benefits have been seen with Paromomycin (25–35 mg/kg orally for 14 days) Nitazoxanide Adults: 500 mg–1 g orally twice daily Length of therapy: 3 days for immunocompetent persons and 2–8 weeks for advanced AIDS patients Other agents that have been used with mixed success in AIDS patients Azithromycin Spiramycin Bovine hyperimmune colostrum Octreotide Reversing immunodeficiency with effective antiretroviral therapy is of greatest importance + Outcome Download Section PDF Listen +++ +++ Follow-Up ++ Symptoms are generally self-limited in immunocompetent patients Parasitologic clearance, however, may take several months The diarrhea may recur or persist in immunodeficient patients, and passage of organisms continues for months to indefinitely Oocysts passed in stools are fully sporulated and infectious; therefore, hospitalized patients should be isolated and stool precautions strictly observed +++ Prevention ++ Water purification Chlorine disinfection is not effective, so other purification measures are needed 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 ++ Persistent diarrhea, particularly in the immunocompromised patient Malabsorption, 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]