Intestinal Parasite (Cryptosporidium) in Dogs

Key takeaways

Cryptosporidiosis in dogs is a parasitic infection with the protozoan parasite, Cryptosporidium. This tiny parasite is ingested in contaminated water or food and infects the intestinal tract, potentially causing diarrhea.

• Most dogs show no symptoms of infection

• Immunosuppressed or young dogs are more likely to develop diarrhea and potentially become dehydrated

• Diagnostic tests include physical examination, bloodwork, fecal examination, and specific testing for parasitic proteins

• Many cases are self-limiting, but anti-diarrheal medications may be used

• Most cases are managed with supportive care such as IV fluids and withholding food

• The prognosis for most cases is excellent, with dogs recovering rapidly

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A closer look: Intestinal Parasite (Cryptosporidium) in Dogs

Cryptosporidium is a parasite that is found worldwide and can cause diarrhea disease in a variety of animals. The parasite is spread through the consumption of the eggs in the feces of an infected host. This can happen through consumption of affected animals feces, contaminated water or prey species, and mutual grooming. These eggs can survive in the environment for several months and are resistant to many methods of cleaning and disinfection. This parasite can spread to humans and infect those that are immunocompromised or at higher risk of disease.

Cryptosporidiosis is common, however developing symptoms of disease is rare. Infections with symptoms are much more common in immunocompromised animals or dogs under 6 months of age. Older dogs can shed eggs of the parasite into the environment without showing any symptoms themselves.

Dogs showing symptoms of diarrhea lasting more than 24 hours or accompanied by other symptoms like appetite loss and lethargy require prompt veterinary attention to determine the underlying cause and prevent dehydration if symptoms are severe.

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Risk factors

In young dogs and puppies, diarrhea caused by cryptosporidiosis can be particularly severe. Immunocompromised dogs are also more likely to develop more severe diarrhea from infection.

Possible causes

Cryptosporidiosis is caused by a protozoan parasite, Cryptosporidium. The eggs of these small parasites are ingested when the dog consumes contaminated water or food. Once in the intestinal tract, the parasites penetrate the intestinal lining and reproduce. After reproduction, the protozoa release eggs into the feces, contaminating the environment, and continuing their life cycle.

Main symptoms

Most dogs show no symptoms of cryptosporidiosis.

Testing and diagnosis

Most cases of cryptosporidiosis go undetected, as dogs typically show no symptoms. Dogs presenting with symptoms of diarrhea undergo diagnostic testing aimed at identifying the underlying cause. These tests may include:

  • Physical examination
  • Blood work
  • Fecal examination
  • Specific testing for proteins of the parasite in the feces

Steps to Recovery

Treatment depends on the severity of symptoms. Many cases are mild and recover with supportive care, such as:

  • IV fluids or electrolytes
  • Withholding food for 24-48 hours
  • Therapeutic diets

A variety of anti-diarrheal medications are commonly used, although there is limited evidence to support their efficacy.

Antibiotics may be indicated for secondary infections.

Patients with more severe symptoms may require hospitalization and ongoing monitoring to prevent dehydration.

Most cases of cryptosporidiosis recover within several days of appropriate supportive care. The prognosis is excellent for most cases. Repeated fecal examinations are recommended to confirm the infection has been cleared, as there may be a risk of further environmental contamination.


Most animal species are susceptible to cryptosporidiosis from ingesting contaminated water, but most species of the protozoa primarily infect only one type of animal. Cross-species infections are uncommon.

Cryptosporidiosis is difficult to control, as contaminated environments are difficult to identify. Dogs that are in good health typically develop no symptoms from infection, so the best prevention involves routine veterinary examinations and keeping up to date on vaccinations and deworming protocols.

Is Intestinal Parasite (Cryptosporidium) in Dogs common?

Cryptosporidiosis is common, but developing symptoms of disease is rare.

Typical Treatment

Supportive care