How can my dog contract Giardia?
Giardia lives and reproduces in the small intestine of host animals. Giardia trophozoites, the free living stage of the organism, form infective cysts that are passed out in the feces. If the cysts are present in a wet or damp environment they can survive in a viable state for a few weeks to several months. Giardia infections are transmitted via ingestion of trophozoites or cysts in contaminated water or food. If a giardia cyst is ingested, the cyst wall is broken down during the digestive process and the trophozoite stage begins to colonize the upper small intestine. Transmission also occurs by direct contact, especially with asymptomatic carriers. More recently, giardiasis has also been recognized as being able to be sexually transmitted. Giardia is so prevalent throughout North America because it is highly contagious. The ingestion of as few as one or more giardia cysts may cause the disease, as contrasted to most bacterial illnesses where hundreds to thousands of organisms must be
