Giardia in Dogs

Giardia is a type of protozoa (single-called micro-organism) that causes intestinal infection. The technical term for this infection is giardiasis. The disease, while rarely fatal, can cause discomfort for you and your dog. Giardia can be contagious to humans and other household pets. Knowing the symptoms and understanding the risks will help you get your dog back to health and prevent the spread of this unpleasant disease.

In This Article

Signs & Symptoms of Giardia in Dogs

Beyond diarrhea, dogs with giardia can also exhibit:

  • Acute diarrhea

  • Weight loss

  • Decreased appetite

  • Vomiting

  • Mucus and red blood in diarrhea

Giardia is usually associated with diarrhea, as it is the most common clinical symptom of giardia infection, and infected dogs can produce large amounts of watery feces. Less common symptoms include decreased appetite, abdominal discomfort, and vomiting. In rare cases, dogs may strain to defecate and even pass red blood and mucus in their stool. However, most dogs infected will be asymptomatic, which means they will show no signs of the disease but can pass it on to other animals.

How Did My Dog Get Giardia?

Like humans, dogs usually acquire giardia by drinking contaminated water. Giardia is found all over the world, transmitted by what medical professionals call the fecal-oral route, which means the parasite is passed through the feces into the environment, where another animal often swallows it. The prevalence of giardia among mammals makes it common in streams, ponds, puddles, and other bodies of still water.

Common causes:

  • Drinking contaminated water

  • Licking contaminated surfaces

  • Eating contaminated food

  • Consuming contaminated feces

There are two stages of the life cycle of giardia: cysts and trophozoites. Trophozoites, the active feeding stage, attach to the small intestine to feed and multiply. They then encyst, and these cysts pass in the feces of infected animals. Sometimes, these feces end up in bodies of water. Giardia in humans got the nickname “beaver fever” after a group of hikers drank from water that had been contaminated with giardia from the resident beavers. Once in the environment, giardia cysts are then consumed by new hosts.

Cysts can survive for weeks in the environment. They are quite resistant, which means as an infected animal passes more cysts, the number of cysts in the environment increases.

Diagnosing Giardia in Dogs

Diagnosing giardia results from fecal testing. Diarrhea is a common symptom of many diseases and conditions. Your veterinarian will ask you for a history of your dog’s symptoms and behavior. He or she may also perform other diagnostic tests to rule out potentially dangerous conditions like toxicity and the parvovirus.

Both cysts and trophozoites pass in the feces of infected dogs. While only the cysts can infect other animals, cysts and trophozoites can help veterinarians identify giardia under a microscope.

Several types of tests can be done to diagnose giardia in dogs. Sometimes, parasites show up on simple saline smears. However, veterinarians may recommend special fecal tests or even antigen tests that look for parasitic protein in your dog’s feces. These tests may need to be repeated multiple times. Cysts shed intermittently, and so it is often crucial to perform repeat testing over a period of days for accurate diagnosis.

Treating Your Dog for Giardia

A combination of medication and environmental management will treat giardia. The most common medicine used to treat giardia in dogs is the deworming agent fenbendazole (Panacur). Additionally, a combination of other medications, like pyrantel and febantel, are available. Metronidazole (Flagyl) is also frequently used to treat giardia. Since giardia can be difficult to get rid of, some veterinarians prefer to treat with fenbendazole and metronidazole simultaneously.

Medications can control parasites within your dog’s body, but recovery depends upon your dog’s immune response. Healthy dogs stand a better chance of a swift recovery than dogs with compromised immune systems or additional infections. Some strands of giardia may also be more aggressive than others, which can prolong recovery. Bathing your dog regularly throughout the infection can help remove cysts from her coat. It reduces the risk of reinfection and lowers your risk of contracting the disease from your dog.

Is There a Cure for Giardia?

Yes. With medication and proper management, your dog can be cured of giardia. However, because giardia is prevalent in most environments, there is a risk of reinfection.

Is Giardia Contagious for Humans and Other Pets?

Giardia can be contagious for humans and other pets. There are several species of giardia, which are broken down further into assemblages. Some are contagious to people as well as an array of mammals, while others are more host specific.

If your dog is diagnosed with giardia, practice good hygiene habits like washing your hands before eating and after cleaning up dog poop. Disinfecting home surfaces with a bleach and water solution (1:32) will destroy the cysts and is essential to use on food preparation surfaces.

What is the Cost of Treating Giardia?

Giardia is a relatively inexpensive disease to treat on its own. It does not require surgery or expensive medications, although it can be present with other conditions that may require costly treatment protocols.

Expect to pay for your dog’s medication, veterinary office visits, and any additional tests. The cost varies depending on location, severity, and whether your dog needs to visit the veterinary emergency room.

Recovery and Management of Giardia

Managing giardia can be frustrating, as reinfection is common because animals are often repeatedly exposed to the parasite once an environment has been contaminated. However, there are steps to avoid this continued exposure.

Cleaning up feces immediately from kennels and indoor runs can prevent infection. Washing these areas with an appropriate cleaner, such as a 1:32 solution of diluted bleach, further reduces the risk of infection.

Some areas cannot be disinfected. Avoid bringing dogs into potentially contaminated outdoor areas that cannot be cleaned for at least a month. This gives the parasite time to decay. If you have followed these protocols and your dog continues to show signs of giardia, it may be time to repeat the treatment or try a new medication. You may also need to treat other animals in the household, as some may be shedding cysts even without showing symptoms.

Preventing Giardia

Giardia cannot always be prevented, but you can reduce your dog’s risk of contracting the parasite.

Prevent your dog from drinking from sources of stagnant water. Streams, puddles, and lakes often contain giardia. Wildlife feces are another source. Prevent your dog from consuming potentially contaminated substances by keeping her leashed, and make sure she always has access to clean, fresh water.

If you and your dogs travel to places with high incidences of giardia, consider giving your dog filtered or bottled water. This will reduce the risk of infection from their drinking water and prevent the potential spread to human members of your family.

Is There a Vaccine for Giardia?

There is no vaccine for giardia. While the parasite is common, it is not as prevalent as other intestinal parasites. Therefore, dogs are not routinely treated with deworming medications for giardia.

Summary of Giardia in Cats

Giardia is a single-celled parasite that causes intestinal issues such as diarrhea, and is highly contagious for other pets and humans. Providing dogs with access to clean, fresh water and restricting their ability to drink stagnant water or consume contaminated material will reduce their risk of infection.

Our medical experts

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