"Giardia"

What is Giardia?

Giardia is a protozoal parasite that commonly affects dogs and less commonly cats. It is most often seen in puppies or dogs that have been around other dogs or contaminated areas. The most common clinical signs associated with Giardia is diarrhea and occasionally vomiting and weight loss. It is transmitted through fecal matter and it is common for patients to re-infect themselves or the environment without decontamination measures.

How is it diagnosed?

There are a number of ways it can be diagnosed. The cysts may be seen on fecal smears. However, not seeing the cysts on a fecal sample does not automatically mean that Giardia is not the cause of diarrhea. The cysts are sometimes intermittently shed and the diarrhea can precede the shedding of organisms. There is also a commercial ELISA test which tests for specific Giardia proteins. The test is similar to the home pregnancy test and gives you a distinct positive or negative.

How is it treated?

In general, the prognosis is good with Giardia. It can be treated with a number of medications or combination of medications. We commonly use fenbendazole, metronidazole, or Drontal as treatments. Another important aspect of treatment is decontamination of the environment. The stools of an infected patient should be promptly disposed of and basic sanitation and hand-washing should be observed. A dilute bleach (1:32) solution will kill the cysts with one minute of contact time. Long-haired dogs should have the hair around their hind end shaved and owners can wipe the hind end after defecation to prevent the cysts from sticking to the hair. Infected dogs should be bathed once a week to prevent recontamination. There is a Giardia vaccine which is used as a treatment adjunct to minimize shedding of the organism, but is generally not recommended to prevent infection.