A few weeks back I took our indoor cat Nestle to the vet because she was having a lot of loose stool and was losing weight.  Imagine my surprise when her stool sample tested positive for Giardia.  How does an indoor cat contract Giardia?

What is Giardia?

Giardia is a protozoan parasite that can live in the small intestines of animals, including humans.  The parasites attach themselves to the intestine wall and cause damage.  Symptoms may include diarrhea, which can be soft and mushy, and often has a green tinge to it.  In some cats, there is mucus in their feces.  It can also cause vomiting and weight loss.

How is Giardia diagnosed?

Giardia can be difficult to diagnose.  A cat infected with Giardia will shed cysts in their feces,  but it is inconsistent and can be missed during a fecal flotation.  If the parasites are present, they may be detected in a fecal smear.  It should be noted that occasionally this method may result in a false positive.

How is Giardia treated?

Some cats are treated with metronidazole which is an antibiotic.  Some cats are treated with fenbendazole which is a broad spectrum dewormer.  Sometimes cats are treated with a combination of the two, especially if the symptoms do not resolve after treatment with only one of the drugs.

How is Giardia spread?

Generally cats become infected when they swallow or inhale the cyst stage of the parasite, usually through contaminated food or water.  Giardia can be spread from animals to humans so proper hygiene should be practiced if your cat is diagnosed with it.

So how does an indoor cat contract Giardia?

Nestle is an indoor cat.  She has never been outside.  She gets fresh water twice a day and fresh food daily.  When the vet said she had Giardia, I was surprised, to say the least.

I am familiar with Giardia occurring in dogs.  But our dogs are checked for worms and parasites each year and more frequently if they have a bout of loose stool for any length of time.  As hunting dogs, they are more likely to come into contact with the Giardia parasite than our indoor cat.  Their last tests were clear.

The only thing I can think of is that Nestle will eat any flies that are unlucky enough to get into the house.  She looks at it as her duty and takes her job seriously.  I did see at least one study where they found the parasite was present on wild caught flies.  Perhaps this is how Nestle contracted it.

Nestle’s treatment and follow-up.

Nestle was prescribed Panacur which is fenbendazole, a broad spectrum dewormer.  The panacur was in a liquid form and administered with an eye dropper for three days, then I waited three weeks and administered a second round.  Nestle was not really a fan of this medication, but I was able to give it to her.  I will wait a bit to give the medication tome to work and take her back in for a recheck.  I will bring a stool sample and check her weight.  It may be that Nestle has more than one issue going on.  Once we are sure that the Giardia is resolved, if she continues to have symptoms then the next step may be an x-ray.

Do you have any theories about how my indoor cat contracted Giardia?

Disclaimer: I am not a veterinarian.  This post is description about our experience.  If your cat is sick or having symptoms, you should take it to a veterinarian.