Giardia

Giardiasis is the intestinal disease caused by the parasite Giardia canis. Giardiasis usually affects dogs, particularly puppies, but can occur in cats. In North America, it’s fairly common in people as well. Giardia is not usually passed directly from animals to humans, but both can come into contact with the same contaminated water source, such as water from a well. Many dogs can pick it up from puddles at dog parks.

The majority of the parasite’s life cycle is spent in the intestines of its unwitting host. The parasite forms a hard cyst that gets passed in feces and is thus spread into the environment.

Diarrhea, severe or mild, is most common sign of giardiasis. The diarrhea can be either intermittent or chronic. Typically there is a high volume of diarrhea with soft, almost frothy, mucous stools. Weight loss and malabsorption can occur. A rancid odor to the feces is often noticed. Usually the diarrhea goes away on its own and the pet is fine, but some severe cases can cause weight loss and general lethargy. The infection is diagnosed with a fecal examination or a Giardia-specific ELISA test. A positive ELISA test, in the absence of clinical signs, does not mean that the pet requires treatment because Giardia is a common inhabitant of the intestinal tract; however, a positive test in a pet with clinical signs can mean that giardiasis is likely involved, and treatment should be undertaken. The Giardia ELISA test can remain positive for several months following successful treatment.

Environmental decontamination is very important when dealing with Giardia.

The most readily available effective disinfectant is bleach ( diluted 1 part bleach to 32 parts water), which is one study required less than one minute of contact to kill Giardia cysts. Organic matter such as dirt or soil is protective to the cysts , so these materials should be removed from cleanable surface prior to disinfection. Animal should be thoroughly bathed once during the course of treatment, and especially before being reintroduced into a “clean” area as infective cysts can stick to the animal’s fur. A properly chlorinated swimming pool should not be able to become contaminated. As for areas with a lawn or plants, decontamination will not be possible without killing the plants and allowing the area to dry out in direct sunlight.