Types of Dog Parasites: Giardia and Coccidia in Dogs 101

While worms in dogs are the largest group of potential intestinal parasites, there are other types of intestinal parasites, like giardia and coccidia, that may also wreak havoc on them. Giardia and coccidia are different than the previously discussed parasites because they are not worms, they're protozoans. Simply put, protozoans are single-cell organisms, like bacteria, but are larger and contain more cell structures; this makes them more related to plants and animals.

Giardia in Dogs

You may have heard the name before, but what is giardia? Giardia is the #1 most common intestinal parasite that can affect your dog and is even more prevalent in puppies. In fact, between 0.44% and 39% of shelter dogs have positive giardia test results.¹ Although possible, the transfer rate from giardia in dogs to humans is rare. Our dogs can become infected with giardia by eating the cyst stage of the parasite, through fecal-contaminated water or food, or by self-grooming if their fur is contaminated with feces. Once ingested, giardia is deposited in the small intestine where it attaches to the intestinal wall and cause symptoms. Giardia symptoms in dogs, include diarrhea and malnutrition.

Diagnosing and Treating Giardia in Dogs

Diagnosing giardia may be difficult since the cyst stage of the parasite is shed in feces sporadically. Vet techs will use a zinc sulfate solution during fecal flotation, which has a lower specific gravity than the sugar solution used in worm detection and does not distort giardia under the microscope. The lower specific gravity allows for the heavy giardia cysts to rise to the top for an accurate diagnosis. Typically, your veterinarian will require multiple fresh stool samples over a period of 5-7 days to fully confirm giardia infection. It’s important when taking these poop samples to your veterinarian that the samples have not been refrigerated and have been collected within a half hour period to prevent death or distortion of giardia.

There is no current drug that is FDA-approved for giardia treatment in dogs. Treating giardia in puppies is costly and takes weeks of follow-up appointments to confirm that it is no longer present. A common veterinary remedy is the off-label prescription of metronidazole for giardia in dogs for 5-8 days, but this treatment has 50% efficacy.¹ Like intestinal worm infections, your veterinarian may recommend using Drontal Plus® for 3 days or Panacur® for 3-5 days for the treatment of giardia.¹ Prevention of giardia is vague. When your dog is undergoing treatment, make sure that they’re receiving baths to remove any fecal debris or giardia parasites. As with any parasitic infection, it’s important to clean up your dog’s poop after defecation. Giardia is not the only intestinal protozoan that you should be aware of, coccidia are also common in dogs.

Coccidia in Dogs

Coccidia is another type of intestinal protozoan group that your pup may acquire, and puppies are most likely to get it. Coccidia in puppies ranges from 3-38% presence in North America.² Depending on the species of coccidia, depends on if they are zoonotic and can be transmitted to us as well as our dogs. Puppies can become infected with coccidia by eating the infective cysts present in soil, grass, etc. or by eating the intermediate hosts such as rodents and rabbits. Coccidiosis in puppies causes inflammation of the small intestine, causing loose stool to watery diarrhea, abdominal pain, anorexia, and weight loss.

Diagnosing and Treating Coccidia in Dogs

As with the other intestinal parasites, coccidia is generally diagnosed by fecal flotation using zinc sulfate solution like when diagnosing giardia. Along with the results of the fecal flotation, your veterinarian will also consider your pup’s history and clinical signs. Upon a diagnosis, there is only one treatment label approved for the intestinal inflammation associated with the coccidia infection: sulfadimethoxine for 5-20 days depending on severity of infection.¹ Another option your veterinarian may prescribe is ponazuril, which is a fairly new drug.¹ To prevent coccidia in puppies, it’s important to clean up your dog’s poop immediately after defecation and to thoroughly clean the kennels, blankets, and beds with high levels of ammonia to effectively kill the cysts.

Comparison of common intestinal parasites in dogs: worms, giardia, and coccidia

There are various types of dog parasites, especially intestinal worms in dogs. Please refer to the table below for a comparison between the main types of intestinal parasites in dogs.

With so many different types of intestinal parasites that can affect your dog, it’s important to seek the advice of your veterinarian on prevention methods. Prevention is your best bet against a costly, time-consuming, and stressful treatment plan against parasites.

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References

1. Sharon Patton. Overview of Giardiasis. Merck Veterinary Manual. September 2013. https://www.merckvetmanual.com/digestive-system/giardiasis-giardia/overview-of-giardiasis#:~:text=Giardia%20spp%20have%20been%20reported,of%20infection%20in%20younger%20animals
2. Comparison Animal Parasite Council. 2020. https://capcvet.org/
3. Hendrix, Charles M., and Ed Robinson. Diagnostic Parasitology for Veterinary Technicians. 5^th Elsevier Inc., 2017.
4. Zajac, Anne M., and Gary A. Conboy. Veterinary Clinical Parasitology. 8^th John Wiley & Sons, Inc., 2012.