Pet Health Library

Parvovirus in Dogs

A puppy with parvovirosis

Background

Canine parvovirus is a highly contagious, potentially fatal viral disease that most often occurs in puppies or adult dogs who haven’t been vaccinated against parvovirus. The virus affects the rapidly dividing cells in a dog’s gastrointestinal tract and bone marrow. The impact of the viral infection on your dog is severe diarrhea and a dangerously low white blood cell count.

Parvovirus is spread through direct dog-to-dog contact or contact with virus-contaminated feces, environments, objects, or people. The virus can survive in the environment for long periods of time, and is resistant to heat, cold, humidity, and drying. Even trace amounts of feces from an infected dog may harbor the virus and infect other dogs. The virus is present in the feces for up to three weeks after infection and recovered dogs may serve as carriers.

Parvovirus can exist in an environment for many months, but it can be inactivated by cleaning thoroughly with a dilute bleach solution (1 part bleach to 30 parts water).

Hot weather, freezing temperatures, snow, and rain DO NOT inactivate this virus.

Risk Factors

Young, unvaccinated or incompletely vaccinated dogs are most susceptible. Any breed of dog can contract the disease, but the risk is higher among the following breeds:

  • American pit bull terriers
  • Doberman pinschers
  • English springer spaniels
  • German shepherds
  • Rottweilers

Signs

Common signs of parvovirus include:

  • Fever
  • Vomiting
  • Diarrhea
  • Lethargy
  • Loss of appetite
  • Abdominal pain

If your puppy or dog shows any of these signs, you should contact your veterinarian immediately. Most deaths from parvovirus occur within 48 to 72 hours following the onset of clinical signs.

Diagnosis

Parvovirus infection is often suspected based on the dog’s vaccination history, physical examination, and laboratory tests. In infected dogs, a complete blood count will show a very low white blood cell count. A quick, in-clinic test performed on a fecal sample can confirm the diagnosis.

Treatment

No specific medication will kill the virus in infected dogs. Nearly all dogs with parvovirus infection require hospitalization. Treatment for parvovirus infection includes correction of dehydration, control of nausea, vomiting and pain until the dog’s immune system can fight off the infection. Because the low white blood cell count leaves the dog open to secondary infections, antibiotic therapy is an essential component of treatment. Food is withheld as long as the dog is vomiting and if vomiting persists, intravenous feeding may be necessary. With intensive treatment, survival rates can approach 90%.

Prevention

Vaccination is critical to preventing parvovirus infection. Young puppies are very susceptible to infection because the immunity provided in their mothers’ milk may wear off before the puppy’s own immune systems are mature enough to fight off infection. If a puppy is exposed to canine parvovirus during this gap period, it may become infected. A series of three or four parvovirus vaccinations, followed by annual boosters, are necessary to ensure a dog is protected.

Regardless of how many doses they received previously, puppies should receive a dose of parvovirus vaccine between 14 and 16 weeks of age. Until a puppy has received its complete series of vaccinations, owners should avoid bringing their pet to places where other dogs congregate (e.g. pet shops, dog parks, puppy classes, doggy daycare, kennels, or grooming salons) because the risk of exposure to parvovirus is high.

Hygiene is essential to halting the spread of parvovirus. Since the virus is highly contagious, isolation of infected dogs is necessary to minimize the spread. Proper cleaning and disinfection of contaminated kennels and other areas where infected dogs have been is critical.

Parvovirus can exist in the environment for many months after an infected dog has recovered but can be inactivated by cleaning thoroughly with a dilute bleach solution (1 part bleach to 30 parts water).

Hot weather, freezing temperatures, snow, and rain DO NOT inactivate this virus.

Canine Parvovirus information sheet

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