Canine Parvovirus

Contributed by:  VetVine Specialty Consulting Service


Parvoviral enteritis (often called "Parvo") is a viral infection that affects dogs.  It is caused by the Canine Parvovirus (CPV-2).  It most commonly affects puppies - especially those that are not fully vaccinated to protect against the disease.  Although the disease can be seen any time throughout the year, Parvo infections most commonly occur in the spring and fall.  This condition can be fatal if not aggressively treated.

Path to Infection

Both dogs and cats can be carriers of the virus (though cats do not become ill from this strain of Parvovirus).  Carriers shed the virus in their stool.  If another dog comes into contact with the affected feces, they can become infected, and in turn become a carrier.  The virus will then multiply in the newly infected dog's intestines and, depending on their immunity, they may or may not become sick. 


Signs of Parvovirus

Parvovirus can affect several organ systems including the stomach, intestines, lymphoid tissue, bone marrow, and the heart.  The signs that can be seen in affected dogs are non-specific but include:

  • vomiting
  • diarrhea (often bloody diarrhea)
  • dehydration
  • lethargy
  • depression
  • decreased appetite
Diagnosis of Parvovirus
In a sick dog, Canine Parvovirus infection may be suspected based on the history, clinical signs and physical examination findings.  Testing of blood, stool, and other diagnostics may be recommended to check for the presence of virus and other complicating factors of infection.

Hospitalization and aggressive treatment is generally required, as affected dogs can become severely dehydrated due to the vomiting and diarrhea. Treatment may include:
  • intravenous fluids
  • anti-nausea drugs
  • medications to protect the stomach and intestines
  • tube feeding or other means of providing nutrition
  • affected dogs are often isolated from other pets to prevent infecting others

The prognosis is variable, but certainly is much worse if a dog goes without treatment.  Dogs with vomiting and/or diarrhea, who become dehydrated, are at increased risk of death.  In dogs that do get treatment, the prognosis can depend on a variety of factors including their blood cell count, degree of damage to intestines and loss of protein, and complications with blood clotting.

Puppies that nurse on their mother's milk after birth generally receive a healthy dose of maternal antibodies to help protect against a variety of diseases.  Within a short period of time, however, those antibodies start to decline, and vaccination is recommended to help the puppy maintain antibody protection against common diseases, including Canine Parvovirus.

Vaccination generally provides protection against Parvovirus.  A veterinarian will recommend what's best for an individual dog, but generally, puppies should be vaccinated every 3-4 weeks until 14-16 weeks of age.  Some breeds, including Rottweilers, may be more susceptible to Canine Parvovirus infection.  Vaccination recommendations for them may be extended to provide as much protection as possible.  

Parvovirus is highly infectious, resilient, and can survive in the environment (bedding and floors) for weeks.  Household bleach is effective for use as a disinfectant when cleaning up after a sick pet.