• Giardiasis is an infection of the small bowel that occurs mostly as a result of fecal-oral transmission or ingestion of contaminated water containing cysts of the protozoan parasite Giardiaintestinalis, which is the most commonly identified intestinal parasite in the U.S.
  • The majority of symptoms, which usually develop 1 to 3 weeks after ingesting the cysts, are gastrointestinal and can include acute and chronic diarrhea
  • The duration of acute giardiasis is usually longer than 1 week and the disease is communicable for as long as the infected person excretes cysts
  • Testing for Giardia should be considered in patients with persistent diarrhea or signs of malabsorption, immunocompromised patients, or patients with a history that suggests exposure (eg, travel, day care)
  • Treatment should include asymptomatic patients with evidence of Giardia cysts in stool samples
  • Antimicrobial medications are effective in most cases; cure rates range from 60% to more than 90%

Urgent action:

  • Severely dehydrated patients require hospitalization to restore electrolyte and fluid balance. This is particularly important in infants and elderly patients