Giardia is a parasite that can infect dogs, cats, and humans. In this post, our San Gabriel vets will discuss the infection, including treatment and prevention.
What is Giardia in dogs?
Both humans and animals can become infected with giardiasis, an infection caused the parasite Giardia. This microscopic parasite attaches itself to the intestinal wall, and has eight different genotypes labelled A to H.
While dogs are typically affected with types C and D, cats are more often infected with type F. Types A and B most commonly affect humans.
Though Giardia in dogs may not always cause issues, it can lead to unpleasant gastrointestinal symptoms like vomiting and diarrhea. This infection is especially dangerous for puppies, senior dogs, and dogs with weakened immune systems.
The disease is not usually life-threatening unless the dog's immune system is immature or immunocompromised.
What are signs and symptoms of Giardia infection in dogs?
Giardiasis can be a significant cause of illness, especially diarrhea, in animals and people. However, most dogs infected with Giardia do not have diarrhea, vomiting, or any other signs of illness.
If you do see any concerning signs of illness in your dog, you should book an appointment for an exam with your veterinarian, as many of the signs and symptoms listed below may point to several health conditions.
When giardiasis does cause symptoms in dogs, they often manifest as:
- Dehydration
- Vomiting
- Diarrhea (acute, sudden onset, and foul-smelling. Can also be chronic and intermittent)
- Fatty stool with a greenish tinge; may contain blood
- Stool that ranges from soft to watery
- Failure to gain weight
- Unexplained weight loss
- Poor coat appearance
When a dog's internal systems are infected with a parasite, it can lead to diarrhea and weight loss. This occurs because the parasite interferes with the dog's ability to absorb nutrients, water, and electrolytes. In puppies, diarrhea can be either continual or intermittent.
Infected dogs also tend to have excess mucus in their feces. Vomiting may occur in some cases. These signs may persist for several weeks. While most dogs do not have a fever, they may be less active. Younger dogs are more likely to display clinical signs.
How are dogs infected with Giardia?
This parasite lives in the intestine and has several sub-species, each targeting a specific group of animals. Despite this, all sub-species have the same lifecycle and method of transmission.
Giardia's lifecycle has two stages. Mature parasites (trophozoites) reside in the small intestine, multiply, and transform into infectious cysts that are excreted in the dog's feces. They can survive for weeks in the environment as cysts until another animal ingests them. Once inside a new host, they transform back into trophozoites and repeat the lifecycle.
Dogs can contract Giardia by drinking contaminated water or by eating grass or other materials that have been in contact with contaminated feces. As we all know, dogs love exploring the world with their mouths, which makes it easy for them to pick up the parasite from the environment. They can drink from puddles, eat other animal's poop, or chew on sticks.
Even if they do not show any signs of infection, our four-legged friends can still transmit the parasite. This is particularly concerning if you have more than one pet. Although it's unlikely to be transmitted from dogs to cats, it's a significant concern among dogs. If one of your pets is diagnosed with Giardia, it's essential to consult your veterinarian to determine the necessary precautions to take with your other pets.
Can I get Giardia from my dog licking me?
It's unlikely that you will contract Giardia from your dog, but it's not impossible. To reduce this low risk, always wash your hands after handling your dog's poop. In humans, Giardia is commonly transmitted through drinking contaminated water, not from their pets. Giardiasis is also known as "Beaver Fever" in people.
If you know that your water source contains the parasite, consider buying a water filter and avoid drinking contaminated water, especially while traveling. This parasite can also be present in soil and on food, so remember to wash all produce before eating and wash your hands after working with dirt.
How Can Giardia be diagnosed and treated?
If you've noticed your dog suffers from diarrhea or other symptoms, call your vet immediately. Your vet will likely perform several diagnostic tests to find out whether your dog has Giardia.
A routine fecal floatation test may not detect the tiny cysts, which are shed inconsistently in the feces and often require a special zinc sulfate floatation solution. Occasionally, a direct smear of the feces can detect parasites.
If your veterinarian suspects giardiasis, they may analyze a stool sample for Giardia-specific antigens (cell proteins). Many cases are diagnosed based on medical history and clinical signs that point to giardiasis.
Your vet may prescribe drugs, including fenbendazole and metronidazole to kill Giardia if your dog has refractory diarrhea (diarrhea that hasn't responded to treatment). These are typically given for 3 to 10 days to treat the infection. Both drugs may need to be administered in combination. Other supplemental drugs may also be prescribed to treat dehydration or severe diarrhea.
A highly digestible, low-residue diet may help lessen loose stools as your dog recovers. Some dogs will need follow-up diagnostic tests and treatments based on their condition and severity of infection. All infected dogs should be re-tested two to four weeks after treatment is completed.
Depending on the results and the severity of your dog's case, a treatment plan can be developed tailored to your dog's needs.
What happens if Giardia is left untreated in dogs?
Left untreated, the disease can cause severe illness and signs such as weight loss and variable levels of dehydration, vomiting, and diarrhea. Dogs that are younger and in their growth phase may not reach their growth potential. The infection may even lead to death.
While many dogs will not show symptoms, they can transfer the Giardia parasite to other dogs when they are at communal places like parks, so it's very important to have a fecal test done during your dog's routine exams, and treat the infection if the test is positive.
Protecting Your Dog From Re-infection & Passing It On
Giardia is a harmful parasite that cannot be prevented by standard tick, flea, and heartworm preventatives prescribed by vets. However, you can take certain measures to keep your dog safe from it.
The most important thing is to ensure that your dog has access to clean and fresh water at all times. Doing so can reduce the risk of your dog drinking from infected puddles and improve their overall health. You can boil your dog's water and let it cool before offering it to them. Alternatively, you can buy a filter that has been proven to remove Giardia cysts if you live in an area where Giardia is prevalent.
Because Giardia cysts are infective immediately when passed into the environment, feces should be quickly removed and disposed of. Always wash your hands after handling dog poop. If you have other animals in the house, even if they are not displaying any symptoms, inform your vet. Your vet may want to put your other pets on medication as giardiasis can be asymptomatic, and other pets could still be spreading the infection.
It is essential to bathe all pets regularly to remove cysts from their hair coat. Also, disinfect your pets' environment daily, including their crates, beds, and food and water bowls. Cleaning should continue until at least a few days after all pets in the household have completed their medication.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. Please make an appointment with your vet for an accurate diagnosis of your pet's condition.