Giardia in Puppies - Symptoms, Diagnosis and Treatment

Keeping your puppy free of parasites

Dog Relaxing On Wet Mud At Field
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Giardia in puppies can cause devastating health problems. Giardiasis is an illness caused by a protozoan, a single cell organism that parasitizes the small intestine. Similar to the protozoan coccidia, canine Giardia infection typically affects pups. Puppies are prone to diseases that older dogs can fight off with a more developed immune system, and up to half of young puppies will get giardiasis.

These intestinal parasites can cause significant trouble given a puppy’s susceptible immune system.

Signs of Giardiasis

The organism compromises the puppy's ability to properly process food. Signs of infection are diarrhea sometimes mixed with mucus and blood. Other times the stool may simply be soft and light colored, or it can even appear normal. The dog often develops a poor hair coat and the tummy swells from gas and looks bloated. Infected puppies may have trouble gaining or maintaining weight. While the illness can be asymptomatic, symptoms show most often among puppies.

Transmission, Diagnosis, and Treatment

The infective cyst stage of the organism lives in the environment, most usually in standing water. Pups tend to contract the parasite by drinking from mud puddles or other contaminated water sources. The disease is also spread through contact with infected feces.

Diagnosis is made with a stool sample in which the veterinarian finds the protozoan during microscopic examination.

However, infected dogs pass the organism only intermittently, and a fresh stool sample may be negative even when Giardia is present. Repeated tests are often necessary before the tiny parasite is detected. Some dogs may not show signs of illness themselves, yet are infected and spread the parasite.

Giardia can be treated with the prescription drug fenbendazole from your veterinarian which effectively removes Giardia cysts from the feces of dogs. (Technically, however, no drugs are actually approved for specifically treating giardiasis in animals.) No side effects are reported, and it is safe for pregnant and lactating animals. Repeated fecal exams will need to be done in a few weeks later to look for any organisms that are still present and make sure the medication is working.

In addition to medication, bathe puppies with shampoo to remove fecal material and associated cysts.


To help prevent the chance of infection, keep the yard clean of feces and restrict your dog's access to unsanitary water helps prevent the chance of infection. (Giardia is one of the most common waterborne diseases in the U.S.)  Environmental areas like grass and standing water are tough to decontaminate, but you can sanitize surfaces by steam-cleaning and cleaning with disinfectants. Allow surfaces to dry completely after cleaning.

Giardia also commonly occurs in kennels and boarding facilities where the disease spreads rapidly due to the crowded conditions. Don't board your dog until your dog he's about a year old.

Giardia is also zoonotic--meaning it can be transferred to humans. If your puppy has it, other people in your family can be carrying the parasite as well, so it's important to treat other family members who are infected.