Coccidia in Dogs: Symptoms, Treatment, and Prevention

Coccidia are microscopic intestinal parasites that commonly affect puppies and can cause diarrhea and other gastrointestinal symptoms. Dogs can become infected by ingesting contaminated feces, food, or water or by eating infected rodents or insects.

Most infections are not medical emergencies, but coccidiosis can become life-threatening in young, small, or immunocompromised dogs.

What Is Coccidia in Dogs?

Coccidia infections in dogs are caused by microscopic, single-celled protozoans in the genus Cystoisospora. These parasites are found throughout the environment and are host-specific, meaning the species that affect dogs infect other dogs rather than people.

Infection with coccidia, called coccidiosis, damages the intestinal lining and can cause diarrhea and vomiting.

After an infected dog passes parasite eggs (oocysts) in their stool, the oocysts develop into an infective stage in the environment within hours to days. When another dog ingests them, the parasites invade and multiply within the cells lining the intestinal tract.

Eventually, infected cells rupture and release more coccidia into the intestines. Over time, this damage can cause symptoms.

Coccidiosis is not usually a medical emergency, but it can become life-threatening in immunocompromised, small, or young dogs. Have your dog examined by a veterinarian if symptoms occur.

What Are the Symptoms of Coccidia in Dogs?

Dogs with coccidia often have no symptoms. When symptoms do occur, they are often mild to moderate gastrointestinal issues.

Symptoms of coccidia in dogs may include:

• Abdominal discomfort
• Dehydration
• Diarrhea, sometimes with blood and excess mucus
• Decreased appetite
• Lethargy
• Vomiting
• Weight loss

While rare, coccidiosis can cause anemia and even death in small or young dogs.

How Do Dogs Get Coccidia?

Dogs get coccidia by ingesting contaminated feces, food, or water or by eating infected rodents or insects.

Dogs at increased risk include:

• Puppies, typically those under 6 months of age, who are commonly affected and more likely to develop symptoms
• Dogs living in overcrowded or stressful environments with poor sanitation or nutrition
• Dogs in breeding facilities or shelters, where more cases may occur

Coccidiosis in healthy adult dogs is rare.

How Is Coccidia in Dogs Diagnosed?

Veterinarians diagnose coccidia in dogs using a fecal examination to look for parasite eggs (oocysts) in the stool.

Fecal examination: A fresh fecal sample is mixed with a solution, centrifuged, and “floated,” allowing oocysts to rise to the top of the test tube. They are then placed on a microscope slide and examined.

Repeat fecal testing: Because dogs may shed the parasites intermittently, multiple stool exams may be required to detect the oocysts.

Additional testing: Your veterinarian may submit feces to a diagnostic laboratory for a more comprehensive examination, including fecal culture and/or a PCR panel to identify causes and rule out other potentially harmful parasites.

Dogs with severe illness may require additional testing, such as blood work.

How Is Coccidia in Dogs Treated?

Not every dog infected with coccidia requires treatment, but when treatment is needed, medication is often effective at clearing the infection.

Your veterinarian may prescribe sulfadimethoxine (Albon) or ponazuril, which are commonly used to treat coccidiosis.

Treatment typically requires a multi-day course of medication. Some cases may require treatment for weeks or repeated courses of medication.

Recovery and Management of Coccidia in Dogs

Most dogs with coccidia can be treated on an outpatient basis, with medications given at home. Dogs that are seriously ill may require hospitalization, IV fluids, and supportive care.

Your veterinarian may recommend a follow-up exam and repeat fecal test to ensure the infection has cleared.

Preventing Coccidia Reinfection

Environmental control is important because dogs can reinfect themselves.

Oocysts are resistant to most disinfectants and can survive for months—up to a year—including through freezing.

To help limit reinfection and environmental contamination:

• Bathe your dog to reduce oocysts on their coat.
• Steam-clean surfaces and use dilute bleach as supplied for environmental disinfection.
• Disinfect or properly dispose of bedding materials.
• Disinfect food and water bowls.
• Disinfect or properly dispose of toys.

How To Prevent Coccidia in Dogs

You can help prevent coccidia in dogs by promptly removing feces, reducing contamination brought into the home, and preventing your dog from eating feces, rodents, or insects.

• Pick up feces promptly. Oocysts require several hours to become infective, so prompt feces removal can help prevent re-exposure and transmission of the parasite.
• Wash your dog's paws and behind. Clean them before your dog comes inside to reduce tracking into the house.
• Prevent scavenging and hunting. Discourage your dog from eating feces, control access to rodents and insects, and maintain effective pest control.