Parvovirus, a dangerous virus in dogs, causes inflamed small intestines. Treatment and survival is possible, but preventing parvo is easier.

Canine parvovirus, often shortened to "parvo," is a dangerous virus that affects dogs and puppies, and it can be deadly if left untreated. But it is possible to protect your pup from this highly contagious virus, by keeping his vaccinations up-to-date and with swift treatment if you suspect your pup has been infected.

Read on to learn how parvovirus spreads and how to identify the signs and symptoms of the disease so you can get your dog the treatment he needs if you suspect he's been exposed to parvo.

corgi puppy lying on the floor
Credit: Paul Park / Getty

What Is Parvovirus and Why Is It so Scary for Dog Owners?

The highly contagious parvovirus causes the animal's small intestines to become inflamed. Dogs are most frequently infected with the virus before the age of 6 months—though older dogs can get the disease too. Dog breeds such as Rottweilers, Doberman pinschers, American pit bull terriers, English springer spaniels, and German shepherds are also at an increased risk for parvovirus infection.

How do dogs get parvo? The gastrointestinal (GI) illness is caused by exposure to vomit, fecal matter, or surfaces and clothing that contain the infective organisms. The incubation period of the infection is four to 14 days, and infected dogs can start transmitting the virus before they show clinical signs. Canine parvovirus is ready to invade unprotected dogs wherever dogs gather—including dog parks, boarding kennels, and even backyards where the virus can linger in the environment for long periods of time—so early vaccination is vital.

Can Humans Get Parvo from Dogs?

According to the Centers for Disease Control and Prevention (CDC), humans cannot get parvovirus from a dog or a cat and vice versa. This is because parvovirus B19 is the only one that infects humans, and this particular strain does not infect animals, and the strains that can infect animals don't infect humans.

That being said, it's always a good idea to use safety gear like gloves and sanitizing products when cleaning up any messes from an infected pet for general health and hygiene, and to prevent the virus from spreading in a multiple pet household.

Parvo Signs and Symptoms in Dogs

"Parvovirus causes gastrointestinal signs—vomiting and foul diarrhea, which is usually bloody and liquid," says Kathryn Primm, DVM, of Applebrook Animal Hospital in Ooltewah, Tenn. "I most often see it in pups aged 5 to 6 months that did not complete the recommended vaccine schedule."

Affected dogs may also develop a fever, lose their appetite, and experience lethargy and general weakness, among other clinical signs. These dogs need help from their veterinarian ASAP.

How to Treat Parvovirus in Dogs

Diagnostic tests that identify the DNA within a fecal sample, along with checking a blood sample, provide a parvovirus diagnosis. Immediate treatment should follow the diagnosis. The parvovirus treatment process is highly involved.

A recent guide to achieving success in parvo treatment involved four stages of therapy:

  1. Treat for shock with fluid therapy.
  2. Rehydrate with intravenous therapy. Affected dogs have lost a lot of moisture through vomiting and diarrhea.
  3. Replace nutrition that was lost through the GI issues.
  4. Take additional nutrition measures to re-establish metabolic maintenance.

If your dog is infected, your veterinarian will review all the particulars of parvo treatment. Now options even allow you to treat a dog at home instead of requiring several nights of hospitalization.

And Primm says treatment for parvo is getting better. "It used to be that more than half of these dogs died, but we have improved our success rates over the years," Primm says. "Still it is expensive and hard on the dog to go through this, so vaccination is absolutely the best idea."

Keys to Preventing Parvo in Dogs and Puppies 

Vaccination is the key to preventing parvovirus. Usually given as a part of a puppy's initial vaccination series, the parvovirus vaccine is part of the DAPP vaccine, a combination vaccination that protects against distemper virus, adenovirus, parvovirus, and parainfluenza virus. 

You and your veterinarian should discuss the right timing for your dog to be vaccinated since guidelines from the American Animal Hospital Association vary based on your pup's age. It is generally recommended three doses of the vaccine be given starting at 6 weeks through 16 weeks of age, administered at intervals of two to four weeks. For dogs older than 16 weeks, two doses are recommended and should be administered three to four weeks apart. 

The vaccine is injected right under the skin. After the initial series of vaccines, your dog should be revaccinated (also known as a booster vaccine) after one year with additional booster vaccines given at three-year intervals after the initial dose.

Because dogs can become part of our families in a variety of ways and at various stages in their lives, Primm says to go ahead and vaccinate if you are unsure if your dog has been previously vaccinated for parvovirus. "In my experience, it is far better to be safe than sorry," Primm says.

Worried about side effects from the parvovirus vaccine? Any vaccine can have risks, though adverse effects are uncommon and usually mild and short-lived. The American Veterinary Medical Association lists possible side effects of the vaccines as slight pain or swelling where the vaccine is administered, a mild fever, or a reduced appetite or activity level. Your veterinarian will help you know what to look for and when to be concerned about side effects from the parvo vaccine.

Keeping Your Puppy Safe from Parvo

The lifesaving measures of vaccination and the necessity of starting behavior training in young pups, which can also be lifesaving, come to a head when it comes to parvovirus.

"I get asked a lot about vaccines and puppy class," Primm says. "I am a firm believer in socializing puppies, but they are NOT fully vaccinated until their last boosters are done between 15 and 16 weeks." So what to do?

"Be smart about it," she says. "If you know your puppy is not finished with vaccines, do not go to dog parks or around dogs you do not know. If you want to expose her to the big-box pet store, for example, just carry her and don't put her down on the floor or to sniff in the parking lot. Many of these pathogens are killed in direct sunlight, so choose areas in the sun for her to learn and sniff."

Extra preventive measures from Primm include discouraging drinking from puddles and eating sketchy things found on the ground.

Parvovirus can have deadly effects, so it's important to take measures to prevent it. If you are unsure if your dog has been protected from parvo, make an appointment now for her preventive vaccinations. And while you're at it, make sure your dog is up-to-date on all of her boosters.