What is Giardia?
Giardia is a single-celled parasitic infection that affects the small intestine of dogs and causes giardiasis. It is caused by the protozoa Giardia intestinalis (also known as Giardia lamblia or Giardia duodenalis) which can be found in soil, food, or water that has been contaminated with feces from infected animals or people [1].
Giardia attaches to the intestinal wall and interferes with the absorption of nutrients, leading to gastrointestinal symptoms. The most common symptoms of giardiasis in dogs include [2]:
- Diarrhea
- Greasy stools
- Weight loss
- Dehydration
- Vomiting
- Gas
In severe cases, giardiasis can damage the intestinal lining and prevent nutrient absorption, leading to malnutrition. Proper treatment is important to eliminate the parasite and allow the intestinal tract to heal.
How Common is Giardia in Dogs?
Giardia is one of the most common intestinal parasites found in dogs. Studies show Giardia affects an estimated 5-30% of the canine population, with higher rates in some high-risk populations. Puppies, dogs in shelters, and dogs with compromised immune systems tend to have higher rates of Giardia infection.
According to research, the prevalence of Giardia in symptomatic dogs ranges from 3.3% to 34% depending on the study. Some key risk factors that make Giardia infection more likely include:
- Puppyhood
- Immunocompromised health status
- Staying in kennels or shelters
- Drinking from streams or bodies of stagnant water
While adult dogs can contract Giardia, puppies less than one year old are at the highest risk. One study found Giardia prevalence was 36% in dogs under 6 months old compared to 12% in older dogs.
How is Giardia Transmitted?
Giardia is transmitted through the fecal-oral route. This means the parasite is shed in the feces of infected animals and then accidentally ingested by other animals. The primary ways dogs can ingest Giardia cysts are:
Contaminated Water – Giardia cysts can contaminate water sources like lakes, streams, ponds, and puddles. Dogs who drink from these sources are at risk of infection. Cysts can survive for months in cold water.[1]
Contaminated Food – Food and water bowls can become contaminated with cysts if they come in contact with infected feces. Giardia can also be transmitted if dogs eat the feces of infected animals.
Giardia cysts are very hardy and can survive for weeks to months in the environment under cool, moist conditions. Good hygiene and preventing fecal contamination are key to controlling transmission.
Diagnosing Giardia in Dogs
Giardia is diagnosed through testing of the dog’s stool. There are two main diagnostic tests that vets use:
Fecal testing: This looks for Giardia cysts in the stool under a microscope. However, because cysts are shed intermittently, they may not always be detectable. Multiple fecal samples tested over several days may be needed for an accurate diagnosis [1].
Antigen testing: This detects Giardia proteins in the feces and is more sensitive than looking for cysts. It requires only one fecal sample and has high accuracy. Antigen tests are commonly used by vets to diagnose Giardia [2].
Treating Giardia in Dogs
There are several medications commonly used to treat giardia in dogs:
Metronidazole – This antibiotic is often the first line of treatment for giardia. It is given at a dosage of 10-25 mg/kg every 12 hours for 5-8 days (1). Metronidazole works by stopping the growth of giardia so the infection can clear.
Fenbendazole – Fenbendazole is an antiparasitic medication used for deworming that is also effective against giardia. The typical dosage is 50 mg/kg once daily for 3-5 days (2). Fenbendazole helps kill off the giardia parasites.
Other potential medications include tinidazole, nitazoxanide, paramomycin, and more. Your veterinarian will choose the most appropriate treatment based on your dog’s specific case, symptoms, and response (3). Typically at least two doses are given over a span of several days to ensure the infection has been fully eliminated.
It’s important to complete the full course of medication as prescribed and avoid interrupting treatment. Follow up testing may be recommended in 2-4 weeks to confirm the giardia has been cleared (1). Keeping the dog’s environment clean and taking preventative measures can also help stop reinfection.
(2) https://todaysveterinarypractice.com/parasitology/giardiasis-in-dogs/
(3) https://vcahospitals.com/know-your-pet/giardia-in-dogs
Preventing Giardia Transmission
There are several key steps pet owners can take to help prevent the spread of giardia between pets and to humans:
Maintaining proper hygiene is crucial. Be sure to wash hands thoroughly after handling infected pets or cleaning up feces. Avoid letting pets lick faces. Disinfect any surfaces the pet may have contaminated (CDC).
Regularly cleaning the pet’s living area and toys can help remove cysts. Feces should be disposed of promptly and litter boxes sanitized daily. Use hot soapy water or disinfectants labeled to kill giardia (Texas A&M).
Prevent pets from drinking standing water, like puddles or birdbaths, where giardia cysts may accumulate. Provide fresh, clean drinking water instead.
Vaccinating Against Giardia
There is a vaccine available to help protect dogs against Giardia. The Giardia vaccine contains inactivated Giardia parasites to stimulate an immune response in dogs without causing infection. Studies have found the Giardia vaccine to be about 78% effective in preventing dogs from developing symptoms after exposure to Giardia according to https://www.ncbi.nlm.nih.gov/pmc/articles/PMC545982/.
The Giardia vaccine is considered a non-core vaccine, meaning it is optional based on a dog’s risk level. It is often recommended for puppies and dogs that frequently visit places like dog parks or boarding facilities where Giardia transmission risk is higher. Some veterinarians may recommend the Giardia vaccine for dogs with previous Giardia infections. The vaccine requires an initial series of two doses 2-4 weeks apart, followed by an annual booster vaccination according to https://wagwalking.com/wellness/these-non-core-vaccines-could-save-your-dogs-life.
While the Giardia vaccine can help reduce the risk of symptomatic illness, it does not provide 100% protection. Vaccinated dogs can still potentially transmit Giardia cysts and proper precautions should still be taken to prevent environmental contamination. But for dogs at high risk of exposure, the Giardia vaccine may provide an extra layer of protection against this intestinal parasite.
Puppy Prevention
Preventing giardia in puppies requires focusing on their deworming schedule and proper socialization.
Puppies should start deworming treatments at 2 weeks old and repeat every 2 weeks until 12 weeks old, then monthly until 6 months old. Deworming helps eliminate any giardia cysts the puppy may have picked up from their mother. Common dewormers used include fenbendazole and metronidazole. Be sure to follow your veterinarian’s recommended deworming schedule for your puppy.
Properly socialize puppies to reduce their exposure risk. It’s important puppies receive positive experiences around new dogs, people, and environments during their critical socialization window. However, avoid areas with high dog traffic before puppies complete their vaccination series around 16 weeks old. Sign up for puppy socialization classes run by a trainer to give them positive controlled interactions. Backyard puppy play dates with dogs you know are healthy can also provide socialization.
Following the deworming schedule and properly socializing puppies will help prevent transmission of giardia during the early vulnerable months. Consult with your veterinarian if you have any concerns about your puppy’s health or socialization progress.
Environmental Prevention
Preventing the spread of giardia in the dog’s environment is a key component of prevention. Some steps to take include:
Clean all water bowls, toys, bedding and other surfaces regularly with hot soapy water to remove cysts. Giardia cysts can survive for months in the environment so regular disinfection is important. Use a disinfectant that is effective against giardia.
Avoid taking dogs to crowded dog parks or areas where giardia transmission is likely. The giardia parasite can spread through contact with infected feces and contaminated environments. Limiting exposure reduces risk.
Promptly pick up and dispose of dog feces, and do not allow dogs access to feces from other dogs. This helps limit environmental contamination.
Bathe dogs after completion of giardia treatment to remove any remaining cysts from the fur and paws.
Outlook and Prevention Summary
In summary, Giardia is a very common parasite that causes gastrointestinal illness in dogs. While it cannot always be prevented completely, there are several key prevention methods that can greatly reduce a dog’s risk of contracting Giardia:
The most important prevention method is proper hygiene – regularly washing hands and disinfecting environments where infected feces could spread. Promptly disposing of dog feces, especially in multi-dog households, is also critical. Bathing dogs after treatment is important to reduce environmental contamination.
Vaccinating puppies against Giardia can provide some protection, though vaccines are not 100% effective. Keeping puppies away from potentially contaminated areas like dog parks and bodies of water can reduce exposure. Providing clean, uncontaminated drinking water is also beneficial.
With prompt diagnosis, proper treatment, good hygiene practices, and some common sense precautions, the prognosis for dogs infected with Giardia is very good. While annoying to deal with, Giardia infections in dogs are manageable if caught early. Prevention is critical and can significantly lower the risk of transmission.