Giardiasis is a gastrointestinal infection that causes diarrhea. It is caused by a parasite called Giardia lamblia, or Giardia intestinalis.
Giardiasis occurs all over the world. The infection is found in the stool of an infected person or animal. It can be excreted into the environment. The parasite has a protective shell that allows it to live for long periods of time in the environment. It can be found in drinking water and in recreational bodies of water, such as lakes. Giardiasis is the most common waterborne disease in the United States.
Giardiasis is spread by contact with the parasite that causes the infection. The parasite can be found in food, water, soil, and other surfaces contaminated by stool from an infected person. A person can be infected in several ways: