Symptoms and Signs of Giardiasis

Medical Author:
Medically Reviewed on 6/20/2022

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-care centers.

The most common symptoms of giardiasis are diarrhea and abdominal pain. The stools may be foul-smelling and float. Other possible associated symptoms and signs can include

These symptoms can vary in intensity from mild to severe.

What Is the Treatment of Giardiasis?

Many people with giardia may not need treatment if they are not likely to spread the infection, and the condition may improve over a few weeks. In other cases, oral medications to treat the parasite are necessary for the treatment of giardiasis. Medications can include metronidazole, nitazoxanide, and tinidazole. In some cases, the condition recurs after medical treatment, and treatment with a different medication, a longer course of treatment, or treatment with a combination of medications may be required.

Must Read Articles:


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