By: Brittany Justice

Basic Info about Giardia

Giardiasis is a diarrheal disease caused by the microscopic parasite Giardia. A parasite is an organism that feeds off of another to survive.

Illness & symptoms are:

  • Diarrhea
  • Gas
  • Greasy stools that tend to float
  • Stomach or abdominal cramps
  • Upset stomach or nausea/vomiting
  • Dehydration (loss of fluids)


  • Swallowing contaminated water
  • Eating contaminated food
  • Person to person contact

Treatments Include:

  • Special Meds
  • Metronidazole
  • Tinidazole
  • Nitazoxanide
  • Paromomycin
  • Quinacrine
  • Furazolidone

Death? & Number of illnesses per year?

  • Deaths due to Giardia is very rare
  • For 2010, the rate of giardiasis was 100,000 and counting

Diagnosis & Detection

Because Giardia cysts can be excreted intermittently, multiple stool collections (i.e., three stool specimens collected on separate days) increase test sensitivity. The use of concentration methods and trichrome staining might not be sufficient to identify Giardia because variability in the concentration of organisms in the stool can make this infection difficult to diagnose. For this reason, fecal immunoassays that are more sensitive and specific should be used.

Rapid immune-chromatographic cartridge assays also are available but should not take the place of routine ova and parasite examination. Only molecular testing (e.g., polymerase chain reaction) can be used to identify the subtypes ofGiardia.