Giardia in Dogs

Giardia is a microscopic parasite that lives in the small intestine. It can affect dogs of any age, although puppies, young dogs and those living or mixing closely with other dogs are more likely to develop symptoms.

In our experience, Giardia is discussed and diagnosed far more often than it was twenty years ago. Better testing and greater awareness may account for at least some of this apparent increase.

Many infected dogs carry and shed Giardia without appearing unwell. Others develop digestive problems ranging from occasional soft stools to persistent or recurring diarrhoea.

How Giardia Spreads

An infected dog passes microscopic Giardia cysts in its faeces.

Another dog can become infected by swallowing cysts from contaminated:

• water;

• soil or grass;

• food or water bowls;

• bedding;

• toys;

• paws or coats; or

• other contaminated surfaces.

The cysts survive best in cool, damp conditions. Reinfection can therefore occur where several dogs share the same environment or where contaminated faeces are not removed promptly.

Possible Signs

Some infected dogs show no symptoms at all.

When signs do occur, they may include:

• soft or watery diarrhoea;

• stools containing mucus;

• pale, greasy or unusually strong-smelling faeces;

• symptoms that improve and then return;

• wind or abdominal discomfort;

• reduced appetite;

• poor weight gain in puppies; or

• weight loss.

Vomiting can occur but is less typical.

Contact your veterinary practice promptly if a puppy becomes lethargic, dehydrated or rapidly unwell, or if there is blood in the stool, repeated vomiting or persistent diarrhoea.

Diagnosis

Giardia cannot be diagnosed reliably from symptoms alone because many other conditions can cause similar digestive upset.

Your veterinary practice may test one or more faecal samples. Giardia cysts are not necessarily passed in every stool, so samples collected over several days or additional testing may sometimes be needed.

A positive result must also be considered alongside the dog’s symptoms, because some healthy dogs carry Giardia without developing illness.

Treatment

Fenbendazole, the active ingredient in Panacur, is commonly used to treat Giardia in dogs.

The correct product, dose and length of treatment should be confirmed with your veterinary practice. Do not give Panacur simply because a dog has loose stools, as diarrhoea has many possible causes.

Some dogs continue to test positive or develop symptoms again after treatment. This may be due to reinfection from the environment, the coat or another dog rather than failure of the medicine itself.

Reducing Reinfection

Good hygiene is an important part of controlling Giardia.

During treatment:

• collect faeces immediately and dispose of them safely;

• wash food and water bowls daily;

• wash bedding at the hottest safe temperature;

• clean crates and washable indoor surfaces;

• wash toys that can be cleaned safely;

• keep the dog’s hindquarters and back legs clean;

• follow veterinary advice about bathing near the end of treatment; and

• avoid communal water bowls, puddles and stagnant water where possible.

Complete removal of Giardia from outdoor ground may not be practical, so prompt removal of faeces and keeping the dog clean are particularly important.

Wash your hands after handling faeces, cleaning contaminated areas or washing an affected dog.

Dogs Without Symptoms

Some healthy dogs carry Giardia without showing any sign of illness.

Not every symptom-free dog that tests positive will necessarily require treatment. The decision depends on factors including the dog’s age, whether other dogs are affected, the presence of vulnerable people or animals in the household and the likelihood of transmission.

Your veterinary practice can advise whether treatment, monitoring or further testing is appropriate.

Our Experience

Over the years, Giardia has become a much more familiar subject among breeders and dog owners.

The important points are not to panic, not to assume every loose stool is Giardia and not to rely on medication alone.

If digestive symptoms persist or repeatedly return, speak to your veterinary practice about appropriate testing and whether treatment with fenbendazole may be suitable.

Correct treatment, prompt removal of faeces and careful hygiene usually give the best chance of bringing the problem under control.

The information on this page is intended as general guidance and should not replace individual veterinary advice, diagnosis or treatment.