Description
Giardiasisis a diarrheal illness caused by a single celled microscopic protozoan parasite, Giardia lamblia, also known as Giardia intestinalis. Giardia lamblia exists in two forms, an active form called a trophozoite, and an inactive form called a cyst. The active trophozoite attaches to the lining of the small intestine and is responsible for causing the signs and symptoms of giardiasis. The trophozoite cannot live long outside of the body and spread of infection is via the cyst, which is excreted in the host's feces. When it is ingested, stomach acid activates the cyst, and the cyst develops into the disease causing trophozoite in the new host. Giardiasis is diagnosed by finding cysts or trophozoites in the feces