By Dr. Gerald Bellin, DVM
Wildwood Animal Hospital and Clinic LLC
Welcome spring! Now that spring “should be” here, snow will be melting and rain will be falling. This increased precipitation results in free standing water. We all know that our furry little friends will find and drink from this standing water, making them more prone to become infected with giardia.
Giardia is a protozoa parasite that may infect both humans and pets, causing diarrhea and sometimes vomiting. These organisms are primarily found in stagnant water and wet soils. They are primarily obtained from drinking out of puddles, ponds, toilets, and other contaminated water sources or muddy soiled areas; even from grooming after out playing in these areas.
Giardia exists in the environment in two forms: trophozoites (trophs) and cysts. Either one is ingested by our pets and could cause diarrhea. The trophs are the active phase, causing problems in pets by attaching to the intestinal lining with a little suction cup like part. These trophs forms are able to move around in the intestines by mode of a flagella. A flagella is a whip-like structure that will whip around to provide movement. The cysts are formed within a few hours of trophs being shed in the feces. The trophs form a protective coating, now called a cyst, and the giardia lies dormant until ingested. The digestive fluids break down the coating to provide two new trophs.
Giardia diagnosis used to be difficult because stool samples needed to be fresh and the organism is mobile, so would swim around and not float to the slide on our standard fecal flotation methods. The new, and much better, way to diagnose giardia is through a fecal test that works very similarly to a pregnancy test and is specific for giardia proteins. The other problem, even with this testing, is that giardia is shed intermittently and may be difficult to detect.
Treatment for giardia is with a broad spectrum de-wormer. However, the combination of an antibiotic, known as Flagyl, tends to be a more successful regimen of treatment. This combined therapy is primarily due to some resistant cases seen.
As mentioned earlier, giardia can infect our pets and us as owners. Giardia is also able to be passed from pets to people and vice-versa. This is known as a zoonotic infection. Zoonosis can easily be prevented by good clean hygiene, along with bathing of our pets to reduce further infection.