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Symptoms and Signs of Giardiasis

Doctor's Notes on Giardiasis

Giardiasis is the most common cause of parasitic gastrointestinal disease. It is caused by an infection of the small intestine with the parasite Giardia duodenalis, also known as Giardia lamblia and Giardia intestinalis. The parasite is typically acquired in situations where there is inadequate sanitation or treatment of drinking water. Giardiasis is a cause of so-called “travelers’ diarrhea”. It can also be spread in any situation where fecal-oral contamination is likely, such as day-0care centers.

The most common symptoms of giardiasis are diarrhea and abdominal pain. The stools may be foul-smelling and may float. Other possible associated symptoms and signs can include bloating, fatigue, malaise, nausea, weight loss, and vomiting. These symptoms can vary in intensity from mild to severe.

Medical Author:
Medically Reviewed on 3/11/2019


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.