Cryptosporidiosis

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

Diagnosis

• 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

Treatment

• 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