In otherwise healthy persons, symptoms can last 4 to 6 weeks. Occasionally, symptoms last longer. Giardiasis is diagnosed by examining a stool sample under a microscope to look for Giardia cysts. Because a stool sample might contain only a few cysts, and they can be easy to miss, diagnosis sometimes requires several tests over several days. The parasite lodges in the upper intestine and can be hard to get rid of, so diarrhea can last for several weeks or months and cause weakness and weight loss.
Dehydration can be a serious problem for children.
Several prescription medicines are available to treat giardiasis. People with severe diarrhea should drink plenty of liquids to prevent dehydration. Giardia parasites are among the most common intestinal parasites is the world. Giardiasis can be caught anywhere and is the most common source of chronic diarrhea picked up while traveling. In the United States, Giardia is one of the leading causes of waterborne outbreaks of diarrhea.