What It Is:
Giardia is a microscopic intestinal parasite that causes diarrhea and digestive upset in cats. The condition it causes is called giardiasis. Giardia is not a worm, but a protozoan, and it lives in the small intestine where it interferes with nutrient absorption.
Cats can carry Giardia without symptoms, but in many cases, especially in kittens or stressed cats, it causes chronic or intermittent soft stools.
🐾 Common Symptoms
Symptoms of giardiasis range from mild to severe and may include:
- Soft, pale, or greasy diarrhea
- Foul smelling stool
- Mucus or occasional blood in the stool
- Weight loss
- Poor coat condition
- Dehydration
- Intermittent vomiting
- Lethargy in more serious cases
Many cats continue to eat and behave normally even with ongoing digestive issues.
🦠 Causes and Transmission
Cats become infected with Giardia by ingesting cysts shed in the feces of another infected animal or contaminated environment. This can happen through:
- Drinking from contaminated water sources such as puddles or shared bowls
- Grooming contaminated fur or paws
- Contact with infected litter boxes, bedding, or toys
- Exposure to other animals in shelters, catteries, or multi cat households
Giardia is highly contagious among cats and can sometimes infect dogs and humans, though cross species transmission is rare.
🔍 Diagnosis
Diagnosis is often made through a combination of history, symptoms, and fecal testing.
Veterinary diagnostics may include:
- Fecal flotation with zinc sulfate to identify cysts under a microscope
- Giardia ELISA test to detect antigens in the stool
- PCR testing for more accurate identification
- Multiple samples may be needed since Giardia cysts are shed intermittently
Because giardiasis mimics other causes of diarrhea, it is often tested along with other parasites.
💊 Treatment
Treatment typically includes anti parasitic medication and supportive care.
Common treatments include:
- Fenbendazole (often for five days)
- Metronidazole (used alone or with fenbendazole)
- Probiotics to restore gut health
- Fluid therapy if the cat is dehydrated
- Bathing or wiping the rear and paws to remove infectious cysts
- Environmental cleaning to prevent reinfection
Disinfect litter boxes and food bowls daily during treatment. Use gloves when handling feces.
🩺 Prognosis
With treatment, most cats recover fully:
- Kittens and immunocompromised cats may take longer to recover
- Reinfection is common without strict hygiene and environmental cleaning
- Some cats may remain asymptomatic carriers
Ongoing diarrhea after treatment may indicate another issue or need for repeat testing.
💡 Cat Owner Note
If your cat has diarrhea that just keeps coming back, it might not be food or stress, it could be Giardia. The parasite is small but stubborn, and it loves shared water bowls, messy litter boxes, and dirty paws. With the right medication and a little cleaning, most cats bounce back quickly.
❓ Frequently Asked Questions About Giardia in Cats
Can indoor cats get Giardia?
Yes. They can be exposed through contaminated water, shared spaces, or other pets in the home.
Is Giardia contagious to humans?
Rarely. Human infection from cats is uncommon but possible. Wash your hands after cleaning the litter box or handling stool.
How long does Giardia last in cats?
With proper treatment, symptoms usually improve in five to ten days. Some cases may take longer.
Can Giardia come back after treatment?
Yes. Reinfection is common if the environment is not disinfected or if the cat is re exposed.
What disinfectant kills Giardia cysts?
Use diluted bleach or veterinary disinfectants labeled for protozoa. Giardia cysts are resistant to many regular cleaners.
Can Giardia resolve without treatment?
Sometimes in healthy adult cats, but treatment is recommended to stop shedding and prevent spread to other animals.