What to Know About Giardia in Cats


In this Article

  • What Is Giardia in Cats?
  • How Do Cats Get Giardia?
  • What Are the Symptoms of Giardia in Cats?
  • How is Giardia in Cats Diagnosed?
  • What Is the Treatment for Giardia in Cats?
  • Will Giardia Go Away on Its Own in Cats?
  • How Do I Protect Myself Giardia?

Giardia are microscopic parasites that can make your cat sick. These parasites live in your cat’s intestines and cause diarrhea and vomiting. Since Giardia is an intestinal parasite, it prevents absorption of nutrients. Your cat’s growth and weight may consequently be affected. 

What Is Giardia in Cats?

Giardia are intestinal parasites. They’re tiny, single-celled organisms that cause disease by destroying the cells that line your cat’s gut. There are several types of Giardia. Cats are mainly infected by Giardia duodenalis.

About 4% of all cats are infected with Giardia parasites. Cats younger than three years are more likely to have this infection.

How Do Cats Get Giardia?

Giardia is transmitted by the fecal-oral route. That means they are passed in the feces by infected cats, and your cat can get an infection by ingesting the cysts in the environment, including in food and water. 

Giardia exists in two forms. The trophozoites cause disease in your cat’s intestines. They are delicate and die soon when passed out in feces. The other form, the cysts, survive in the environment for several months and infect your cat when ingested.

Your cat could get Giardia infection by:

  • Coming into contact with feces from an infected cat
  • Playing or walking through contaminated soil
  • Licking their body after being in a contaminated cage, crate, or litter box
  • Drinking water from a contaminated pond, creek, or puddle

What Are the Symptoms of Giardia in Cats?

Your cat may or may not have noticeable symptoms after Giardia infection. Giardia is an intestinal disease, and the symptoms are related to the digestive system. Younger cats that get infected are more likely to have symptoms, including:

  • Diarrhea is the usual symptom. Feces may be pale, and you may see mucus or blood in stool.
  • Weight loss occurs because the parasite destroys intestinal cells that absorb nutrients. 
  • Vomiting may occur.

How is Giardia in Cats Diagnosed?

Typically, Giardia infections are diagnosed by examining the cat’s stool under a microscope. Trophozoites of Giardia are more likely to be found in liquid stools of diarrhea. Cysts are seen in fully formed stools.

Immunofluorescence and enzyme-linked immunosorbent assay (ELISA) are serological tests. They are carried out on stool samples. ELISA is considered a dependable technique for diagnosis of cat Giardia.

The polymerase chain reaction (PCR) is also done on stool samples and can detect the subtype of Giardia. It is more dependable than microscopy for the diagnosis of Giardia in cats.

What Is the Treatment for Giardia in Cats?

Giardia can be treated at home. Your cat is not likely to be sick enough to require hospitalization, but diarrhea has many causes, and some of them can be dangerous. You should have your pet examined by your veterinarian. 

If your cat has a Giardia infection, your veterinarian will prescribe a course of treatment. The two preferred drugs are fenbendazole and metronidazole. Your veterinarian will prescribe either or both of them for 5 to 7 days. 

If one of your cats is getting Giardia frequently, you should consider treating all of the cats in your home.

Will Giardia Go Away on Its Own in Cats?

Giardia could go away without treatment. Either your cat eliminates Giardia from its intestines, or the disease becomes asymptomatic. 

It is likely that cats can go from infected to uninfected on their own. Cats under the age of one year have a high prevalence of Giardia infection. Older cats rarely have Giardia, suggesting that they’re able to eliminate the infection on their own.

How Do I Protect Myself Giardia?

The Giardia that infects your cat is unlikely to infect humans and cause disease, but it’s sensible to take precautions:

  • Wear gloves when gardening, cleaning your infected cat’s litter box, and cleaning their fur.
  • Clean and disinfect your home and your cat’s toys, bedding, and food bowl.
  • Wash hands with soap after playing with your pets, especially before preparing food or eating.

Show Sources


Advisory Board on Cat Diseases: “Giardia infection in cats.”

The Canadian Veterinary Journal: “Giardia.”

Centers for Disease Control and Prevention: “Giardia and Pets.”

Companion Animal Parasite Council: “Giardia.”

Veterinary Parasitology: “Endoparasite prevalence and recurrence across different age groups of dogs and cats” “The prevalence of Giardia infection in dogs and cats, a systematic review and meta-analysis of prevalence studies from stool samples.”

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