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Key Features

  • Cryptosporidia cause severe and devastating diarrhea in patients with AIDS and in other immunodeficient persons

  • Humans acquire the infection from

    • Contaminated drinking water

    • Recreation water sources

    • Close contact with infected humans or animals

  • Most human infections are caused by C parvum or C hominis, although other species have been reported to cause human disease

  • Children younger than age 2 years are more susceptible to infection than older children

Clinical Findings

  • Diarrhea

    • Can be self-limited diarrhea (2–26 days) with or without abdominal cramps

    • Can be mild and intermittent or continuous, watery, and voluminous

    • May be accompanied by low-grade fever, nausea, vomiting, loss of appetite, and malaise

  • Severe, prolonged, chronic diarrhea

    • Tends to develop in immunocompromised patients (either cellular or humoral deficiency)

    • Can result in severe malnutrition

    • Subsides only after the immunodeficiency is corrected

  • Other clinical manifestations in immunocompromised persons include

    • Cholecystitis

    • Pancreatitis

    • Hepatitis

    • Biliary tree involvement

    • Respiratory symptoms


  • Visualization of Cryptosporodia oocysts in the stool is diagnostic

  • Direct immunofluorescent antibody (DFA) of stool is the test of choice for visualizing oocysts

  • Oocysts can also be visualized with a modified Kinyoun acid-fast stain on concentrated stool

  • ELISA and point-of-care rapid tests are commercially available and superior to conventional microscopy


  • Immunocompetent patients and those with temporary immunodeficiencies respond to nitazoxanide, antidiarrheal agents, and hydration

  • Immunocompromised patients usually require more intense supportive care with parenteral nutrition in addition to hydration and nonspecific antidiarrheal agents

  • Nitazoxanide for 3 days is the treatment of choice; recommended doses are

    • 100 mg (5 mL) every 12 hours for children 12–47 months of age

    • 200 mg every 12 hours for 4- to 11-year-olds

    • 500 mg every 12 hours for children 12 years or older

  • For patients with advanced AIDS, antiparasitic therapy alone has not proven efficacious

  • Institution of effective antiretroviral therapy results in elimination of symptomatic cryptosporidiosis

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