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Information ⬇

Giardiasis can be diagnosed by parasite antigen detection in feces, by identification of cysts (oval, with four nuclei) or trophozoites (pear-shaped, flattened parasites with two nuclei and four pairs of flagella) in stool specimens, or by nucleic acid amplification tests. Given variability in cyst excretion, multiple samples may need to be examined.

Treatment: Giardiasis

  • Cure rates with metronidazole (250 mg tid for 5 days) and albendazole (400 mg/d for 5-10 days) are >90%; tinidazole (2 g PO once) may be more effective. Nitazoxanide (500 mg bid for 3 days) is an alternative agent.
  • If symptoms persist, continued infection should be documented before re-treatment, and possible sources of reinfection should be sought. Prolonged therapy with metronidazole (750 mg tid for 21 days) has been successful.

Outline ⬆

Section 7. Infectious Diseases