Canine parvovirus, often called parvo, is a highly contagious virus that affects most canids (dogs, wolves, foxes, and coyotes). This potentially fatal disease attacks rapidly, deteriorating a dog's bone marrow and gastrointestinal tract. Infected dogs quickly become weak, dehydrated, and anemic. Puppies are most vulnerable and often die of this disease. Fortunately, vaccinations greatly reduce a pup's chances of contracting parvo.
What Is Parvo?
Parvo is a virus that causes severe diarrhea, vomiting, dehydration, and lethargy in dogs. It is contagious among all dog species but is not transmissible to humans.
Symptoms of Parvo in Dogs
Parvovirus attacks rapidly, dividing cells in a dog's bone marrow and intestines. Once the bone marrow is affected, the dog's white blood cell count drops, raising the risk of infection, and the immune system begins to shut down. When the intestinal cells are affected, the lining of the intestines becomes damaged and the body is no longer able to absorb nutrients or properly digest food. The external signs of this internal destruction include:
Parvo typically causes diarrhea that is bloody with an odor far worse than a dog's normal feces.
As the disease takes its toll on the body, the dog will become extremely weak and dehydrated. The dog may develop sepsis, which is an infection of the blood that can happen when the intestinal walls cannot act as a barrier against bacteria.
Not all dogs with parvovirus will exhibit severe symptoms. In some cases, adult dogs may contract the disease with minor symptoms (or none at all) but may infect other dogs.
Causes of Parvo
Parvo most commonly affects puppies, but adult dogs can contract the disease if they are unvaccinated. A dog whose immune system is compromised (due to another medical condition) is also at risk for parvo. Here's how dogs contract the disease:
- Ingestion: A dog becomes infected with canine parvo after coming into contact with microscopic particles of the virus from contaminated feces. The virus enters the dog's system through the mouth. It then takes about three to seven days for the disease to become active in the body.
Diagnosing Parvo in Dogs
Your dog's medical history and symptoms play a big role in the diagnosis of parvo, but the final diagnosis is usually made after a lab test confirms the presence of the disease.
Most veterinarians will run a test on a stool sample to detect antibodies for parvovirus, which will indicate whether an animal has been infected. Many vets have an in-house test kit to speed up diagnosis. Results are usually available within 15 minutes.
If the parvo test is positive, your vet will most likely recommend further lab work to assess the damage the disease has caused to the blood cells and organs.
The sooner your vet can assess your dog, the better its chance of recovery. Do not wait to see your vet if your dog has any signs of illness.
Unfortunately, there is no cure for parvo. The cornerstone of treatment is supportive care. Ideally, this involves hospitalization and intensive nursing care. General treatment involves the following:
- Intravenous fluids to rehydrate
- Antibiotics to prevent sepsis
- Anti-emetics or anti-nausea drugs to combat nausea and vomiting
- Antacids to prevent further damage to the stomach lining and esophagus due to nausea and vomiting
- Deworming because the presence of intestinal parasites can increase the damage caused by parvo and hinder recovery
Other treatments may be recommended depending on the dog's condition and the veterinarian's professional opinion. These may include anti-inflammatory drugs, antiviral drugs, plasma transfusions, and more. In addition, lab work will need to be repeated periodically to monitor the dog's overall condition.
Home treatment is not generally recommended for parvo because it is not as effective. However, if the cost is a major factor and an owner is dedicated, home care may be attempted instead of euthanasia. It is essential to know about your dog's care and follow medical recommendations. Survival is less likely with home care, but not impossible.
Prognosis for Dogs with Parvo
If your dog is being treated for parvovirus, expect a hospital stay of about a week, give or take. Be prepared for a significant cost (several hundred to thousands of dollars, depending on the case). In general, the survival rate with proper treatment is about 70 to 90 percent.
Once a dog has recovered from parvo, attentive care must continue. It is important to finish any course of antibiotics that your vet has prescribed. Your vet might also recommend continuing anti-nausea and/or anti-diarrhea drugs for a few days.
Expect your dog's stool to be loose for a few days as the intestinal tract is still healing. Reintroduce food gradually, beginning with a bland diet prescribed by your vet.
It is a good idea to bathe your dog well during and after the recovery process. Your dog will continue to shed parvovirus for up to 2 weeks after recovery. Therefore, it should not be allowed in any public areas for that time. In addition, it should be kept away from puppies and unvaccinated dogs.
Fortunately, once fully recovered, parvo dogs do not tend to have any residual health problems and retain immunity to the disease for a few years—possibly for life.
How to Prevent Parvo
Because parvo is such a deadly and contagious disease, prevention is crucial. Here's how to protect your dog or puppy from parvo:
- Vaccinate your puppies and adult dogs. Be sure you see your vet regularly and that you report any signs of illness promptly.
- Do not take your puppy to public places or around unknown dogs before it reaches 17 weeks of age and is fully vaccinated. A puppy's immunity is unknown up to about 16 weeks of age, and vaccine-induced immunity is not fully effective until five to 10 days after the vaccine.
Because parvovirus is highly contagious to other dogs, measures must be taken to decontaminate areas where a parvo positive dog has spent any time.
Even if a parvo dog has spent a brief time in an area and has not defecated there, you must decontaminate the area. Remember that the parvovirus can remain on a dog's paws and fur and can be transported this way.
At the vet hospital, parvo dogs are placed in isolation and veterinary staff cleans up with a bleach solution or a special disinfectant that is known to kill the parvovirus. Most household chemicals will not kill parvovirus, so consult your vet regarding proper home disinfection methods.
Generally, parvovirus will not live indoors for more than a month or so, but you should still be sure to thoroughly clean the area. Soiled bedding should be thrown away, sealed in a plastic garbage bag before doing so, or washed in hot water and bleach.
If puppies or unvaccinated dogs are living in the home, they should be kept away from contaminated indoor areas for at least a month.
Outdoor areas are much more difficult to disinfect. Parvovirus can live outdoors in above freezing temperatures for five to seven months, depending on conditions.
It is only safe for your dog to return to bleached areas after they are completely dry. Overall, your best bet is to keep puppies and non-vaccinated dogs away from the area until you can be sure the virus has died off.
Is Parvo Contagious to Other Animals?
Parvi is very contagious to other dogs and wild canine species. An infected dog will shed viral particles in its stool during the active phase of illness and for a few weeks after recovery.
Parvovirus is stable in the environment for a long time and remains viable in areas where dogs play and relieve themselves. People's shoes can easily pick up the virus and transport it to other areas. A dog does not necessarily need to come into direct contact with feces to contract parvo.
Canine Parvovirus. American Veterinary Medical Association.
Canine Parvovirus. Merck Manual Veterinary Manual.
Canine Parvovirus Information for Dog Owners. American Kennel Club Canine Health Foundation.