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Canine Parvovirus: Causes and Treatments

Written by Ella White


Gentle dog resting quietly
  • Canine Parvovirus is highly contagious and is spread by contaminated feces
  • It's resistant to a lot of disinfectants and can survive indoors for up to a year 
  • It's included in the standard shots all puppies should have 
  • Humans can't catch Parvo from dogs but we can get Parvovirus B19 - the human strain
  • Depending on how server the infection is, a healthy dog can begin to recover within five to ten days
  • Around 80% of dogs that contract Parvovirus will survive 
  • Although there's no cure, early detection and professional vet treatment is essential  

Canine Parvovirus, or parvo, is a serious illness contracted by dogs and is most common in puppies and adolescent animals. Highly contagious, hard to kill, and with the ability to exist in the environment for a long time, parvo poses a serious threat to dogs that have not been vaccinated against it.

But what is Canine Parvovirus? What are the symptoms of parvo? Can parvo be treated? And is parvo fatal for dogs? We’ll explore all these questions and more in this blog.

How Do Dogs Get Parvo? 

Canine Parvovirus is spread by contaminated feces. But because it can live in the environment, including on surfaces, dogs don’t have to come into direct contact with parvo-contaminated poop to contract the virus.

Parvo is highly contagious, so it spreads not just quickly but very efficiently between dogs that might be carrying it on their fur and paws, where it will spread to the ground and other surfaces like bedding and even human hands.

Though it’s not airborne, the virus can live outside for months on surfaces and floors, and in dog stools. It’s even resistant to a lot of disinfectants, and vets tend to use specialist bleaches specifically known to kill the virus which prevents it from spreading in medical settings.

Why Do Puppies Get Parvo?

One of the core vaccinations that puppies are required to receive is the Canine Parvovirus vaccine. Puppies get this series of three shots at around 6, 8, and 12 weeks old but they are vulnerable to parvo until they’ve received all three. They should also receive a shot at around 14-16 weeks to ensure complete protection.

Puppies aged up to six weeks old are still able to benefit from the antibodies passed down by their mother. So the babies of a vaccinated dog should be immune until around this time. 

Between the ages of six weeks and six months old, puppies are more susceptible to Canine Parvovirus. This is because they will not have developed immunity as a result of their shots yet, and their own immune systems will not be fully developed and able to fight off viruses.

Are Some Dogs More Likely To Get Parvo?

Studies have suggested that some breeds are more susceptible to parvo or suffer more severely when infected. Owners of the following breeds should be aware of this susceptibility and be extra careful when taking their puppies outside before fully vaccinated:

  • American Staffordshire Terrier
  • Doberman Pinscher
  • English Springer Spaniel
  • German Shepherd Dog
  • Labrador Retriever
  • Rottweiler

Can Humans Get Parvo?

Humans can get Parvovirus B19, which is the strain specific to humans rather than dogs. Similarly, there is a different strain that affects cats. This means that humans cannot catch parvo from dogs, but we can carry their virus on our hands and clothes.

For this reason, it’s important never to touch a dog or clear up the feces of a dog that you know has Canine Parvovirus without wearing the correct protective equipment. 

Though you will not contract the virus from this contact, you could easily spread it to other dogs and, as we’ve already mentioned, most domestic antibacterial cleaners will not be strong enough to kill it.

What Are The Symptoms Of Parvo?

There are a number of symptoms that puppies infected will display, starting within three to seven days of them contracting the virus. First they will be very tired and lethargic and might start to refuse their food.

Next they are likely to develop a fever followed by extreme diarrhea and vomiting. Dogs with parvo will lose weight due to the food refusal and diarrhea and vomitings, and might collapse as a result. The infection along with dehydration might also cause hypothermia and an increased heart rate.

If you notice that your dog has developed any of these symptoms, contact your vet immediately. Even if your dog does not have parvo, these symptoms could indicate another serious illness:

  • Lethargy
  • Depression
  • Lost appetite
  • Fever
  • Diarrhea, often with blood
  • Vomiting
  • Weakness
  • Weight loss
  • Dehydration
  • High heart rate
  • Hypothermia

How Is Canine Parvovirus Diagnosed?

If you take your dog to the vet to be tested for Canine Parvovirus, the most likely way they will run tests is using a fecal swab. Also known as an ELISA (enzyme-linked immunosorbent assay) test, this should only take about 10 minutes to show results.

Though dogs can take three to seven days to display symptoms, it can take even longer for them to shed viral antigens. Therefore, further testing might be needed if your dog’s test shows negative but it’s believed that they are suffering from parvo.

What Happens When A Dog Has Parvo?

There are four stages to the Canine Parvovirus:

  1. Infection
  2. Incubation
  3. Illness
  4. Recovery

When the dog comes into contact with contaminated feces or environments, they will become infected with parvo.

Over the next three to seven days, the virus will attack the cells that divide most rapidly – often the tonsils or lymph nodes – so it can more effectively multiply throughout the body. This is the incubation period.

Once incubated it spreads further throughout the dog’s systems, for example into the bone marrow, small intestines, or even the heart, they will begin to show symptoms of illness, mentioned above.

This illness is caused by the virus attacking immune cells and decreasing the dog’s white blood cell levels. When it enters the digestive systems, it causes the worst symptoms like vomiting and diarrhea.

Fortunately, Canine Parvovirus does not usually kill infected dogs and, after the illness has passed, they begin to recover. This typically takes five to ten days, but can be longer depending on how severely the infection attacks their body.

Most dogs that die as a result of parvo actually die from shock or dehydration. For this reason, it’s very important to make sure your dog gets enough water and nutrients during their recovery process.

How Long Does Canine Parvovirus Last?

Canine Parvovirus can last for ten days or more, with most dogs admitted to the vets with the virus staying for five to seven days. Dogs with parvo are most likely to die from the illness within 24 to 72 hours of first symptoms.

However, the good news is that 75-80% of dogs with parvo will survive. The quicker you can get them to the vets, the better.

How Long Is Parvo Contagious For?

Canine Parvovirus can survive indoors for around one month, and outdoors for up to a year. In infected dogs, the virus is contagious for a shorter period, but it can be hard for owners to know exactly the duration of the shedding time.

Though dogs are likely to begin shedding the virus within 5 days of infection, this does not necessarily start at the same time as symptoms are displayed. So the gap between infection and illness can mean a dog is contagious before their owner knows they have contracted the virus.

Even after they have recovered, dogs with parvo can shed the virus for up to 10 days, so should be kept away from unvaccinated dogs for at least this amount of time if not longer.

How Is Parvo Treated?

There is no direct cure for Canine Parvovirus. So if your dog contracts the virus and is hospitalized, their care will focus around preventing the virus from spreading further and helping them to fight it off.

This will usually involve intravenous drips to help increase their fluid levels, ensuring they get the correct nutrition which may need to be provided via a feeding tube, preventing vomiting and diarrhea, and regulating blood sugar levels and electrolytes.

Do not try to treat your dog at home. Dogs with the virus are more likely to die if their symptoms are not treated within 72 hours at most. So hospitalization and veterinary care is their best chance of survival.

As an outpatient, vets will recommend continued care to increase their fluid levels (which might involve subcutaneous hydration), prevent vomiting and diarrhea, and ensure they are eating a diet that is easy to digest and won’t cause further upset.

Because parvo can develop into sepsis, hospitalized dogs might also need further antibiotics to prevent this bacteria from entering their bloodstream. 

How To Prevent Canine Parvovirus In Dogs

To prevent this long, distressing, and expensive process, which can leave infected pups with life-long health issues, all dogs should be fully vaccinated against Canine Parvovirus.

The course of vaccinations should happen within a set timeframe from the age of six weeks. If too much time passes between shots, the full course might need to be started again to ensure full immunity.

To prevent parvo in dogs that have not yet received all of their vaccinations, avoid allowing puppies to socialize with unvaccinated dogs. Owners should always be conscious to keep their dogs away from animal feces which could be infected, and always avoid dogs that you know have been infected and could be shedding the virus.