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Giardia in Cats: What You Need to Know

Diarrhea and upset stomach are both common symptoms that accompany parasitic infections known as Giardasis. Here, our Cumming vets talk about the signs of Giardia in cats, what you should know about it, and how you can treat your feline friend if they become infected.

What is Cat Giardia?

Giardia duodenalis is a protozoan parasite that can infect many different mammals, including humans, cats, and dogs. Different strains of Giardia are categorized by the letters A to H. Cats generally become infected with the parasite from Giardia strain F, whereas humans are typically susceptible to assemblages A and B. On the other hand, while rare, cats can harbor strains A and B, potentially infecting their owners. 

This condition is most often seen in kittens and cats that are suffering from poor health as the result of other underlying conditions.

Giardia can be hard for pet owners to deal with because treatment isn't always effective and reinfection often occurs.

How does Giardia spread among cats?

All strains of giardia are transmitted via the fecal-oral route. This means that the giardia parasites are present in an infected cat's stool, when other animals (or people) come in contact with the infected stool the parasite makes its way into the new host's body through ingestion or inhalation. This can happen by direct contact with contaminated stool, by the inhalation of soil that has been in contact with contaminated stool, or by ingesting water that has become contaminated.

Can you get Giardia from your cat?

While humans can contract Giardia, it is commonly transmitted through drinking water.

While it is possible for cats to harbor the A strain of giardia (dogs can harbor the B strain) that people are susceptible to, the spread of giardiasis from cats to people is not very common. This also answered the question 'Can a dog infect a cat with Giardia?', and the answer to this is no, as they both contract different strains of Giardia.

Nonetheless, we recommend taking precautions such as wearing gloves while changing cat litter, washing your hands well after handling your cat, and disinfecting items that come in contact with your cat (including the litter box, water bowls. bedding, toys, etc.). People with compromised immune systems should be particularly diligent about disinfecting if their cat is diagnosed with giardia.

Disinfect surfaces that your cat comes in contact with using a solution of chlorine bleach at a dilution of 1:16 or 1:32.

Signs & Symptoms of Giardia In Cats

Giardia parasites can damage a cat's intestinal wall and typically lead to a sudden onset of foul-smelling diarrhea. Not all cats infected with Giardia will show signs of infection, however, if your cat has giardiasis you may also notice:

  • Excess mucus in the feces may be apparent.
  • The cat's stool is soft to watery and may have a greenish tinge or contain blood.
  • Lethargy in some cases.
  • Vomiting may occur in some cases.

The symptoms of giardiasis listed above may persist for several weeks in cats which could cause weight loss. It's also not uncommon for diarrhea related to giardiasis to be intermittent.

If your cat has a Giardia infection then they will not generally develop a fever.

How are cats treated for Giardia infections?

It can be challenging to completely treat giardia in cats. To completely get rid of the parasite, repeated treatments or a combination of different treatment methods might be required. Eliminating the disease can be difficult because some giardia strains can be resistant to medication. As a result, multiple drugs or more than one attempt at therapy may be needed.

Fenbendazole and metronidazole are the treatments most often prescribed for giardia in cats.

  • Fenbendazole may reduce clinical signs and shedding of the parasite. This treatment is administered to the infected cat orally for 3 to 5 days and is safe for pregnant cats.
  • Metronidazole is a medication that appears to be more effective at treating giardia in cats than dogs. Treatment is given for 5 to 7 days and is not safe for pregnant cats.

Your vet may recommend two different medications used together to successfully treat a Giardia infection.

Your vet may also prescribe a highly digestible diet until your cat's stool hardens. Prolonged bouts of vomiting and diarrhea can quickly result in dehydration, so it's important to ensure that your cat remains well-hydrated.

How long will my cat have Giardia?

It generally takes between 3 to 5 days for the parasites to be cleared from the stool once antibiotic treatment begins, and 5 to 7 days for symptoms to resolve.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

If your cat is showing any of the signs of Giardia mentioned above, please contact our Cumming vets today and schedule an appointment.

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