Parvovirus FAQ

What is parvo?
“Parvo” is short for parvovirus. Parvo is a virus that eats away the lining of the intestines. Symptoms of parvovirus typically include vomiting, lethargy, and diarrhea. The diarrhea is often blood tinged as the lining of the intestines is literally being shed out into the stool because of the virus. Parvovirus can easily turn into a deadly disease in a very short period of time.

How is parvo treated?
There is no “cure” parvo because parvo is a virus. There is no cure for a virus in human or animal medicine, however any viral infection should be treated with supportive care to ensure the best possible outcome. Think of it as a human having a stomach virus, although there is no cure you still take medicine to treat your symptoms and drink plenty of fluids to keep yourself hydrated. Parvo is much more urgent in the fact that it is life threatening, but the same concept applies.

It is important to remember that dogs do not die from the virus itself, they die of dehydration, malnutrition, and/or sepsis secondary to the virus. Therefore controlling the vomiting and diarrhea, keeping the dog hydrated through IV fluids, and giving them injectable antibiotics is absolutely vital to give this animal the best possible chance of beating the disease.

We start treatment for parvo by placing a catheter in your dog’s vein to begin fluid therapy. Fluid therapy will not only replenish the fluids lost because of the vomiting and diarrhea, but it will also maintain them on the fluids they would be consuming if they could keep anything down. Fluids are given as a steady drip rather than simply under the skin so that absorption into the circulation is direct. Potassium is commonly added to the fluids in order to maintain electrolyte balance. Dextrose (sugar) is also frequently added as the stress of the disease may lower blood sugar, especially in a small puppy.

The second way parvo kills is through bacterial invasion of the circulatory system (sepsis). The intestine is normally full of bacteria and when the parvovirus ulcerates the intestine there is little to prevent the bacteria from marching easily into the bloodstream. With the GI tract damaged, antibiotics cannot be given orally. They are given either as shots or are added into the IV fluid bag. Remember antibiotics cannot kill a virus like parvo but they can help to prevent secondary infections.

The third thing we do is attempt to manage the patient’s nausea. Patient comfort is an important part of treatment for any disease but is especially important for parvo treatment as these puppies feel extremely nauseated. Again, the GI tract is too damaged for oral medication so medications are given as injections. The vomiting typical of parvo infection is not only uncomfortable but can ulcerate the esophagus. The disease itself ulcerates the stomach and small intestine. We also will give your dog injectable antacid medications to help heal these ulcers and minimize their formation.

We will also test your dog for intestinal parasites and treat them accordingly. Puppies are our typical parvo patients, and puppies commonly suffer from parasitism. The last thing we need are additional parasites causing issues in the GI tract.

Does parvovirus affect puppies only or can adult dogs contract the disease?
The most important factors in whether parvovirus infection occurs seem to be the experience the dog’s immune system has had with the virus plus the number of viral particles the host is exposed to. In the 1970s and early 1980s when the virus was new, all dogs young and old were susceptible, but now that the virus is everywhere, all dogs, even the unvaccinated ones, have at least some immunological experience with this virus. Any exposure, no matter how small, is likely to generate some antibodies. Also, vaccination is a widespread process nowadays and it is likely that a dog has had at least one vaccine at some point. Will these antibodies be enough for protection? In general, the answer seems to be yes as infection in dogs older than one year is somewhat unusual. It is important to realize, however, that this observation should not be taken to mean that adult dogs should not continue their vaccinations. Even though infection is somewhat unusual in adult dogs, adult dogs should still continue their vaccinations as this is a life-threatening disease for which treatment is expensive. No chances should be taken. The vaccine for Parvovirus immunizes dogs against other viruses and bacteria that cause disease, as well.

The short answer to this question is technically yes, dogs of all ages are susceptible, however the disease is much more prevalent in puppies at this point in time than it is in adult dogs.

What are my dog’s chances for survival?

With proper hospitalization, survival rates approach 80%. Without hospitalization, chances are significantly lower than 50%. However, even with hospitalization some dogs have a better chance than others. The younger the puppy and the smaller the puppy, the smaller the chances of survival. A 6 month old great dane puppy has a much better chance than a 6 week old yorkie puppy even if both dogs receive the same treatment. It also helps if the dog has received at least one vaccine in its puppy series. The most important things you can do to increase your dog’s chances are to start treatment as soon as they start showing symptoms, and treat with hospitalization.

How can you tell if it is truly parvo or some other virus?

Parvoviral infection must be considered as a possible diagnosis in any young dog with vomiting and/or diarrhea. We do have an in-house test that we perform on all dogs that are suspect of parvo; however, it is possible to get a false negative on this test, so it is best to proceed with caution and treat it as if it is parvo. The optimal treatment for any stomach virus is the same supportive care we provide our parvo patients.

How much does it cost to treat my dog for parvo?

This question varies for every patient. Prior to hospitalization your doctor will go over a proposed treatment plan with you that should give you an idea of how much it should cost. The doctor will discuss with you prior to treatment, how far you are willing to pursue treatment from a financial standpoint. Obviously, dogs that take longer to recover will cost more than one that recovers more quickly. Also, the larger the dog the more the cost will be because they require more medication and more supplies in general. A typical case requires 5-7 days of intensive care in hospital, therefore it’s safe to assume this will be a fairly costly venture.

How did my dog get parvo?

Vaccination history, strength of the immune system, and exposure are all huge factors. Parvo has been around since the 1970s, is hard to disinfect, and is shed in extremely large numbers by infected dogs. This means that there is virus everywhere: on every carpet, on every floor, in every yard and park. Virus is shed in the stool for the first two weeks or less after the initial infection but only a tiny portion of infected stool – which could be months old depending on the environmental temperature and humidity – is needed to infect a non-immune dog. Some dogs become what is called subclinically infected, which means they do not appear particularly sick. These animals tend not to be confined since no one knows they are infected, thus they can spread virus around a large area depending on where they leave their droppings.

How do I prevent parvo from spreading? How do I disinfect the environment?

Canine parvovirus is especially hardy in the environment. It is easily transmitted via shoes or clothing to new areas. It is able to survive freezing temperatures in the ground during winter, plus many household disinfectants are not capable of killing it indoors.
Here is what we know about how contaminated an environment is likely to be:
Infected dogs shed virus (in their stool) in gigantic amounts during the 2 weeks following exposure. Because such enormous amounts of virus are shed, there is a HUGE potential for environmental contamination when an infected dog has been there.
It is important to realize that because the canine parvovirus is so hardy in the environment, it is considered ubiquitous. This means that NO ENVIRONMENT is free from this virus unless it is regularly disinfected.
A parvoviral infection can be picked up ANYWHERE although it is easier to pick up an infection in an area where an infected dog has been simply because of the larger amounts of virus in a contaminated area.
Whether an individual dog gets infected or not depends on the number of viral particles the dog experiences, what kind of immune experience the dog has had with the virus before (vaccinated? previously infected? how much past exposure?), and how strong the individual dog is (stress factors, diet, etc.).
A typical/average infectious dose for an unvaccinated dog is 1000 viral particles. For some dogs far less is needed. For other dogs, far more is needed. An infected dog sheds 35 million viral particles (35,000 TIMES the typical infectious dose) per OUNCE of stool.

Indoor decontamination:
Indoors, the virus loses its infectivity within one month; therefore, it should be safe to introduce a new puppy indoors one month after the active infection has ended.

Outdoor decontamination:
Freezing is completely protective to the virus. If the outdoors is contaminated and is frozen, one must wait for it to thaw out before safely introducing a new puppy. Shaded areas should be considered contaminated for 7 months. Areas with good sunlight exposure should be considered contaminated for 5 months.
Of course, the above presupposes that no decontamination steps (other than waiting) have been taken. In most households, owners want to know how to disinfect their homes to create a safer environment for the other dogs there or to create a safe environment for a new or replacement puppy.

Here’s what we know about disinfection:
Despite the introduction of new cleaners with all sorts of claims, parvovirus remains virtually impossible to completely remove from an environment. The goal of decontamination is to reduce the number of viral particles to an acceptable level. Lysol does not kill parvo.

The best and most effective disinfectant against viruses (including parvoviruses) is BLEACH. One part bleach is mixed with 30 parts water (or 1/2c bleach per gallon of water) and is applied to bowls, floors, surfaces, toys, bedding, and anything contaminated that is colorfast or for which color changes are not important. At least 10 minutes of contact time with the bleach solution is needed to kill the virus. Steam cleaning is also able to kill the virus.

Disinfection becomes problematic for non-bleachable surfaces such as carpet or lawn. Outdoors, if good drainage is available, thorough watering down of the area may dilute any virus present. Since carpet is indoors, it may be best to simply wait a good month or so for the virus to die off before allowing any puppies access to the area.

Is parvo contagious to humans or cats?

Many species of animals have their own parvovirus, most are species-specific (not infectious to other species). Fortunately canine to human transmission of parvovirus has never occurred. There is some debate over whether or not parvo is contagious to cats. Some experts believe that canine parvovirus is directly related to feline distemper a.k.a. panleukopenia. We know that panleukopenia is caused by a parvovirus, and a cat with feline distemper will test positive on a canine parvovirus test. Therefore it is probable that dogs and cats may pass this back and forth, so proper precautions should be taken. Panleukopenia is included in standard annual vaccination protocols for cats, and virtually every cat is exposed at some point so most cats should have some level of immunity. The vaccine is very effective, and even if your cat has only had it once in it’s whole life it may very well provide it with the protection it needs. However, panleukopenia is considered significantly more fatal in cats (around 90% mortality rate) than parvovirus is in dogs so taking the proper precautions and disinfecting surfaces with dilute bleach (1 part bleach to 30 parts water, with at least10 minutes of contact time) is essential.

How long do I need to confine my dog from other dogs after returning home?

Infected dogs shed virus (in their stool) in gigantic amounts during the 2 weeks following exposure. Because such enormous amounts of virus are shed, there is a HUGE potential for environmental contamination when an infected dog has been there. A typical/average infectious dose for an unvaccinated dog is 1000 viral particles. For some dogs far less is needed. For other dogs, far more is needed. An infected dog sheds 35 million viral particles (35,000 TIMES the typical infectious dose) per OUNCE of stool. So absolutely 100% confine your dog for a minimum of two weeks. We generally recommend confining dogs for two weeks after they leave the hospital to be completely sure they are no longer contagious although this may be longer than necessary.

Can my dog reinfect itself after returning home?

The short answer to this question is no, but technically not entirely impossible. Because parvo is a virus and not a parasite, your dog’s immune system should protect it from reinfection once it is had the disease. Any normal dog with a healthy immune system will not get parvo again. Think of it like the chicken pox (also a virus) in humans. Many of us had chicken pox as small children, after we had it once we did not get it again even after being directly exposed to the virus. However, every once in a very great while there would be a child that got chicken pox twice although they weren’t nearly as ill as they were the first time. Therefore, the answer is no your dog should not get parvo again however we cannot guarantee this.

How does having parvo as a puppy impact their lifelong health?

A typical puppy that has survived this disease goes on to live completely normal lives with no long term side effects. Do not worry that because your dog was sick as a puppy that it will be this sick and costly to care for it’s entire life.

How soon after having parvo can my dog be vaccinated?

This question may vary based on doctor preference but typically one week after symptoms have completely subsided it is safe to vaccine. We do not want to vaccinate them while they are sick because vaccinations can suppress their immune system and make it harder for their body to fight off the virus.

Why does my dog have to be hospitalized, Why can’t I just treat it at home?

Home treatment for parvo infection is a bad idea when compared to hospitalization and intensive care. Mortality rises substantially and the heavy diarrhea and vomiting lead to heavy viral contamination in the home. In addition to this dogs with parvo cannot be given medication by mouth when they have parvo for several reasons: the first is that with severe vomiting it is not likely your pet will keep the medications down at all, and secondly this virus causes severe damage to the GI tract meaning that these medications cannot be absorbed properly and may not work at all. While fluids and injectable medications can be given under the skin, it is best it they are given into the vein where they have direct access to the bloodstream.

Works Cited:

  • Wendy C. Brooks, DVM, DABVP ”Caring for the Recovered Dog” 1/1/2001 (Accessed 8/3/11) Veterinary Information Network
  • Wendy C. Brooks, DVM, DABVP ”Feline Distemper (Panleukopenia)” 9/17/2009 (Accessed 8/3/11) Veterinary Information Network
  • Wendy C. Brooks, DVM, DABVP ”How Parvo Infection Happens” 9/23/09 (Accessed 8/3/11) Veterinary Information Network
  • Wendy C. Brooks, DVM, DABVP ”Parvo: the Physical Illness and its Treatment” 12/06/2010 (Accessed 8/3/11) Veterinary Information Network
  • Wendy C. Brooks, DVM, DABVP ”What is Parvo?” 6/11/09 (Accessed 8/3/11) Veterinary Information Network

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