Giardia lamblia

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Giardia lamblia

  • Characteristics
    • Parasite
  • Transmission
    • Fecal-oral transmission
      • Consumption of trophozoites or cysts released in stool of infected people
      • Usually in contaminated water (e.g. outdoors, camping, hiking, traveler)
        • Small inoculum needed (<10 organisms) to infect GI tract
  • Presentation: Giardiasis
    • Non-bloody steatorrhea
      • Foul-smelling fatty yellow diarrhea
      • Due to malabsorption from parasitic colonization of jejunum and ileum
      • Non-bloody as parasite does not invade intestinal wall
    • Abdominal pain, bloating, flatulence are also seen
    • Increased risk with IgA deficiency
      • Secretory IgA normally prevents adherence of microbes to GI mucosa
      • May be caused by selective IgA deficiency or X-linked agammaglobulinemia
  • Diagnosis
    • Stool O&P (ova and parasite exam)
      • Specific use of stool microscopy; trophozoites and cysts seen in stool
    • ELISA for antigen detection is also used
  • Treatment
    • Metronidazole