Canine Parvovirus (Parvo) Overview

Canine parvovirus is a very contagious small virus that affects the gastrointestinal tract of dogs. In young puppies, it may also damage the heart muscle. Canine parvovirus is commonly referred to as “parvo.”

Canine parvovirus will infect dogs, wolves, and foxes, but will not affect cats. Parvovirus is spread through the waste of infected dogs. Its origin is unknown. First discovered in 1978, canine parvovirus had spread worldwide by 1980. Parvovirus is able to survive a wide range of pH and temperature ranges and remains in infected soil for a long time.

Spread of Parvo

Dogs are frequently infected when they ingest the dog waste of infected dogs. Even if your dog does not eat poop, his paws may come in contact with infected waste during daily walks or trips to the dog park. When your dog or puppy cleans ups afterwards he will ingest small amounts of this waste and may become infected.

At about four months of age, puppies are generally vaccinated against parvovirus. Puppies that have not been vaccinated are at the highest risk for becoming infected.

Symptoms of Canine Parvovirus Disease

80% of infected dogs will show no signs, but will continue to spread the virus through their waste. Infected dogs may develop the disease if their immune systems are weak due to stress or if their immune system is focused on fighting other infections, such as Salmonella or other parasites. Disease symptoms include loss of appetite, bloody diarrhea, and vomiting. Most deaths occur within 72 hours of displaying signs of infection.


Viruses in people and dogs can be extremely difficult to treat. Parvovirus treatment primarily involves a strong focus on keeping the infected dog hydrated and comfortable. Treatment may also include transfusing blood plasma from a donor dog that has survived canine parvovirus. The hope is the blood plasma will help provide passive immunity to the infected dog to help it recover.

After recovery from parvovirus, a dog—and especially its waste—will remain contagious for about two months.

Canine Parvovirus Prevention

The most important thing you can do to prevent parvovirus infection is to vaccinate your dog as soon as possible. The second most important thing is to practice good hygiene. Keep your dog away from infected dogs and pick up and dispose of all dog poop promptly.

Parvovirus is difficult to kill. A bleach solution of at least 30 parts water to one part bleach is the only known household disinfectant proven to kill the virus.

To ensure the safety of all your family members, all DoodyCalls Technicians are trained on proper disinfecting techniques and carefully disinfect their boots and tools with a strong bleach solution between each yard.


  • The Merck Veterinary Manual contains an extensive Canine Parvovirus entry.
  • The Wikipedia entry on Canine Parvovirus also contains extensive information about the spread, treatment, and prevention of Canine Parvovirus (Parvo).
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