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Giardia Clinical Features/Laboratory Diagnosis
  • Clinical Features:

    • "The spectrum varies from asymptomatic carriage to severe diarrhea and malabsorption. 

    • Acute giardiasis develops after an incubation period of 5 to 6 days and usually lasts 1 to 3 weeks.  

    • Symptoms include;

      •  Diarrhea

      •  Abdominal pain

      •  Bloating

      •  Nausea

      •  vomiting. 

    •  In chronic giardiasis the symptoms are recurrent and malabsorption and debilitation may occur."

  • Laboratory Diagnosis:

    • "Giardiasis is diagnosed by the identification of cysts or trophozoites in the feces, using direct mounts as well as concentration procedures. 

    • Repeated samplings may be necessary. 

    • In addition, samples of duodenal fluid (e.g., Enterotest) or duodenal biopsy may demonstrate trophozoites. 

    • Alternate methods for detection include antigen detection tests by enzyme immunoassays, and detection of parasites by immunofluorescence. 

      • Both methods are available in commercial kits."

  • Treatment:

    • The Medical Letter recommends metronidazole (Flagyl) as the drug of choice, with tinidazole, furazolidone, and paromomycin as alternatives.

  • courtesy of the Division of Parasitic Diseases at the National Center for Infectious Diseases, Centers for Disease Control & Prevention

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