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Giardia And Giardiasis In Cats

Apr 13, 2014 · Updated Nov 26, 2018 · ·
  1. Anne
    If your cat has recently been diagnosed with Giardia, or even if you just suspect he or she might have it, you're probably fraught with questions. How dangerous is Giardia? Can I get it from my cat? What do I need to do to get rid of Giardia in my home? We've thoroughly researched the topic to bring cat owners solid helpful information.

    Giardiasis is an intestinal infection caused by a parasite. The main symptoms are diarrhea, abdominal pain and sometimes vomiting. However, many conditions can cause these symptoms, so only your veterinarian can actually diagnose giardia.

    Giardia is neither a worm nor a bacterium, but a one-celled protozoan, so tiny it’s microscopic. Cats usually get giardia by ingesting the organism, which then makes its way into the intestines. There, it attaches to the intestinal walls and starts to divide and multiply.

    That's Giardia in a nutshell. Let's take a closer look to learn more about diagnosing, treating and preventing this infection.

    Symptoms and Diagnosis of Giardia in Cats

    Giardia attacks the cat's digestive tract, bringing on some or all of the following -
    • Diahrrea (sometimes starting out as soft stools)
    • Abdominal pain.
    • Vomiting and nausea.
    • Dehydration.
    • Weight loss (if the course of illness is prolonged)
    If you're not sure how to tell if your cat has stomach pain, read our guide: 35 signs that your cat may be in pain.

    Symptoms are most noticeable in younger cats and can be sudden, chronic, intermittent or even temporary.

    This is what often delays diagnosis and treatment. Just as you’ve decided Kitty needs a trip to the vet, diarrhea stops. The first thing that comes to mind is, “He must have eaten something he shouldn’t have and now is over it.” In fact, the parasite is still there, but just not as obvious.

    The main symptom of giardiasis in cats is diarrhea. Many times it is a sudden onset of acute diarrhea, foul-smelling, sometimes greenish in hue and possibly even tainted with some blood.

    Feces may be of varying consistency, and sometimes mucus is present as well. Cats can live with chronic giardiasis, which can be asymptomatic for a while, flaring up into intermittent or chronic diarrhea at other times.

    More acute forms of chronic diarrhea due to giardiasis can develop in cats with weaker immune systems, such as kittens, senior cats and FIV or FeLV cats.

    Chronic diarrhea can be life-threatening to a cat since dehydration is a result.

    How do you recognize dehydration? Disorientation, lack of coordination, panting, depression, lack of activity, loss of elasticity in the skin (a pinch of skin stays pinched instead of smoothing out immediately), sunken eyes, loss of appetite, dry mouth and a rapid heartbeat.

    Instead of being her usual self, Kitty may sleep even more and move around less. Like humans, cats could go without food for a short time, but water is essential to blood circulation, digestion, elimination, and brain function, as water makes up 80% of a cat’s body.

    The best way to be sure just what is the cause of diarrhea is to have the veterinarian do a swab test. Inflammatory Bowel Disease (IBD), an inability to absorb nutrients from food, and malnourishment could be other causes.

    Fecal testing can have false results so that you think your cat is healthy while parasites are still present. This can be the fault of the test or because parasites don’t show up in every swabbing.

    If Kitty has been tested and pronounced healthy, but still has chronic diarrhea, before jumping to the conclusion it’s something else, ask for a fecal antigen test in addition to a regular fecal float. It checks for any giardia antigens present.

    How Cats Become Infected with Giardia

    The parasite, in the form of cysts, is shed through feces, and that is one way for cats to get giardia. However, the parasite also likes a cool, damp environment. Almost all animals in shelters develop giardia because of the close living quarters and extreme exposure. For dogs, if a shelter hoses down the floor where a dog has pooped, and the dog then licks up some of the water, he could acquire the cysts. In a home situation, only 11% of cats have the parasite. If Kitty grooms an infected cat, he could be infected too.

    Giardia can damage the lining of the intestines and interfere with food absorption or digestion. Many cats diagnosed with Inflammatory Bowel Disease (IBD) have a history of Giardia infections.

    Treatment of Giardia in Cats

    Your veterinarian will prescribe medicine for Kitty, most likely an antibiotic such as Metronidazole (Flagyl) or Panacur. It’s also a good idea to give Kitty baths during this time, since reinfection could occur as Kitty sheds the cyst parasites.

    Even if you don't bathe your cat, make sure you maintain a good level of hygiene. Clean the litterbox thoroughly and don't forget to wash your own hands frequently before and after you handle Kitty's litter or food every time.

    House cleaning regime for Giardia

    If your pet has Giardia then some of the parasites are shed in the feces - into your home. Don't freak out just yet. What you need to do is disinfect all items that may become contaminated.

    According to the CDC, you should disinfect the following items daily -
    • Litter box (at least around the edges).
    • Water and food dishes.
    • Cat toys.
    • Pet beds.
    • Linens in your home where your cat likes to spend time.
    Repeat the daily cleaning and disinfecting of these for as long as your cat is sick with Giardiasis and until a few days after the last course of antibiotics had been administered.

    Can giardia be passed from cats to humans?

    While humans can become sick with Giardiasis, fortunately, the strains that attack cats and dogs are different. Which means the risk of contracting Giardia from your cat is small. Nevertheless, you should practice good hygiene when handling your sick cat. The CDC suggests these safety measures:
    1. Wash your hands regularly and thoroughly.
    2. Disinfect household items that your cat comes in contact with.
    Regardless of Kitty's illness, the CDC also suggests that you wear gloves when working in the garden as you could contract human strains of Giardia right in your backyard (nothing to do with your cat!)

    Final words

    Giardia is a common infection, often easily treated but not so easily diagnosed. While antibiotics can be effective, there are resistant strains out there. It can even be lethal in kittens or cats with a weaker immune system. Keep Giardia at bay by treating quickly and sticking to a good cleaning regime.

    If Kitty develops diarrhea, a trip to the veterinarian is warranted. Diagnose and treat Giardia - or any other ailment - quickly and effectively!

    Over to you -
    Have you ever had a cat diagnosed with Giardia? Share your experience in a comment below so others can see it too. And if you're currently dealing with Giardia and need help, please use the cat forums for that (we can't answer questions posted as article comments).

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    weebeasties and (deleted member) purraised this.


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  1. calicosrspecial
    Thank you for a great and helpful article.

    I always do a PCR Diarrhea test to check for giardia or other issues. It is expensive but I believe it is worthwhile.

    When I have cat with giardia I isolate them and follow the many instructions mentioned in this article. The cysts are especially difficult to eradicate so using heat (steam, boiling water) and bleach (making sure it is rinsed off to remove it from the surface) have been important to avoid any re-contamination.

    Bathing a cat is also very important IF it is possible. Using a shampoo that contains chlorhexidine can be helpful in reducing the risk of the cat re-contaminating themselves. But please research this to make sure the advice is correct.

    Here is a very good link that was very helpful to me:

    Giardia Questions

    Please feel free to send me a message if you have any questions as I am happy to try to help.
      Anne and PushPurrCatPaws purraised this.
  2. catspaw66
    Flagyl is the worst tasting substance in the world. I had to take it when I caught C. diff. Your cat may be very hard to dose with it.
  3. 1craziercatlady
    Great article...i have one specific cat that is prone to diarrhea, but since this boy is FIP+ and usually only gets it when the disease flairs up we figured it was symptoms of the disease. Lately he has been so runny that he "leaks" but w/ no sign of disease flare-up so i will now be sure to ask for the antigen test. Thank you!
      Athenaglaukopis and Anne purraised this.