What is giardiasis?
Giardiasis is a diarrheal illness caused by Giardia intestinalis (also known as Giardia lamblia), a one-celled, microscopic parasite that lives in the intestine of people and animals. The parasite is passed in the stool of an infected person or animal. The parasite is protected by an outer shell that allows it to survive outside the body and in the environment for long periods of time.
