A little lesson in Veterinary Medicine: Giardiasis

I thought I'd take this opportunity to share some information with folks out there about the health conditions that have affected Freja in the time she has been with our family. First, let's talk about Giardiasis.

Giardiasis is a protozoal infection that can affect people, dogs, cats, birds and many other species. What is a protozoal infection you ask? A protozoal infection is infection with single-celled organisms called protozoans. The protozoan that causes Giardiasis is called Giardia. There are multiple species of Giardia, but Giardia in dogs is often referred to as Giardia canis. These little critters can only be seen under a microscope. Here is a link to a photo of what Giardia looks like under the microscope: http://plantphys.info/organismal/lechtml/images/giardia.jpg. As you can see, Giardia is a flagellate, which means it has a tail or tails that it uses to propel itself around.

So, you may be wondering, how does your pet become infected with Giardia? By ingesting the Giardia cysts. Protozoan species go through a series of life stages, one of which is the cyst stage. Protozoan cysts are very tough and can survive for along time exposed to the environment, especially if the conditions are right for them (i.e. high humidity is good for Giardia cysts). How do cysts get into the environment? Simple: feces. They are shed from the intestines of infected animals or people and then contaminate water or surfaces that come into contact with feces. Think about all of the places bird feces touch and you will see how easy it is for these microscopic hitchhikers to spread around. This is why it is important not to drink surface water that's not purified and not to let your pets drink from puddles.

What happens to your dog (or cat or YOU) when Giardia runs amok in the intestines? It builds up on the inside of the intestines, prevents absorption of nutrients and causes diarrhea, and sometimes also nausea and vomiting. If your dog (or cat or YOU) are not getting proper nutrient absorption overall health can be impacted. It can certainly affect your dog's (or cat's or YOUR) immune system and make your dog (or cat or YOU) more susceptible to other infections. While there is some scientific evidence indicating that some animals (and people) can carry Giardia in their systems with no ill effects to themselves (and therefore act as vectors or agents to spread the cysts around), for most dogs, cats and people Giardia causes illness.

So, how is Giardia treated? By medications that kill protozoans such as Metronidazole (also called Flagyl). When Freja had Giardiasis she was treated with Metronidazole. It is a very strong drug that has its own share of side effects, but it is very effective at killing protozoans.

For more information about Giardiasis in pets please see the relevant article in The Merck Veterinary Manual.