Coccidiosis in Dogs

Coccidiosis is a gastrointestinal disease in dogs caused by a parasite from the Isospora species. Dogs are infected with I. canis, I. ohioensis, I. neorivolta and I. burrowsi. Infection occurs when the animal ingests the infective form (sporulated oocyct) of this parasite in stool. It can also be contracted by eating an intermediate host for Isospora such as a rodents or bugs especially cockroaches. The infective oocysts (eggs) release sporozoites that invade the cells lining the intestines. These organisms can reproduce sexually or asexually and begin producing more infective oocytes in as little as 12 hours! The good news is that Isospora are species specific which means it is not zoonotic.

The parasite is usually seen in young puppies where it causes straining, gas, vomiting, dehydration and/or bloody diarrhea. In severely debilitated animals, it may cause death due to dehydration. It often occurs in pups who are infected with parvovirus because it surpasses their immune system. Rarely, it is also seen in adult dogs who are immunosuppressed or immunocompromised.

Diagnosis is made by performing a fecal examination and finding the Isospora oocysts. Since normal animals may pass a few of these on occasion, the diagnosis is made based on clinical signs in combination with a positive fecal. Another form of coccidia called Eimeria is often found on fecal analysis of dogs. This organism does not cause disease in dogs. It is seen in dogs who eat droppings from birds, rabbits and rodents. In the United States, sulfadimethoxine (Albon) is used to treat this parasite. Most puppies love the taste of Albon making it an easy mediation to administer.

The oocystes of Isospora are resistant to most chemical disinfectants including bleach.  Feces should be removed immediately followed by steam cleaning as it is the only method that will kill oocytes on surfaces. Also, it is important to remove fecal material from the pup’s paws and anus. I recommend using a baby wipe on the pup’s anus after every bowel movement. Don’t forget to check the paws for stool stuck between the toes.


Shell, Linda. Coccidiosis. Associated Database – VIN, Last updated 4/21/2011.


Published by kristennelsondvm

Dr. Kristen Nelson grew up on a farm in Watertown, Minn., where she developed a deep love for animals of all kinds. She received a Doctor of Veterinary Medicine degree from the University of Minnesota, College of Veterinary Medicine. Kris then completed a small-animal internship at the prestigious Animal Medical Center in New York City. In addition to writing and speaking, she cares for small and exotic animals in Scottsdale, Az. Dr. Nelson is widely quoted in the media. Her credits include Ladies’ Home Journal, USA TODAY, the Los Angeles Times and numerous radio and television interviews. Dr. Nelson has written two books, Coated With Fur: A Vet’s Life and Coated With Fur: A Blind Cat’s Love. Kris and her husband Steve share their home with rescued cats, birds and a dog.