Giardiasis is an intestinal infection caused by a microscopic, single-celled parasite known as Giardia lamblia. A parasite is an organism that lives on or inside another organism called the host. Typically found in lakes, streams, or ponds that have been contaminated by human, muskrat, dog, or beaver feces, giardiasis is also known as "beaver fever."
Giardia lamblia is one of the most common human parasitic infections in Canada. Higher numbers of infections are seen in the late summer months and even a few deaths have been reported. Travellers to regions of Africa, Asia, and Latin America where clean water supplies are low are at increased risk of contracting the infection.
Some healthy people do not get sick from Giardia lamblia; however, they can still pass the infection on to others. Children, the elderly, and people with long-term illnesses may be especially prone to contracting the illness, as the risk of transmission is higher in daycare centres, chronic care facilities, and seniors' residences.