Since puppies have immature immune systems, they are more susceptible to illnesses caused by viruses, bacteria, and parasites. One common and potentially fatal puppy disease caused by a virus to watch for is the highly contagious parvovirus, also referred to as parvo. Learning how puppies can be infected, what symptoms to look for, and how to prevent parvo are vital to protect your puppy.

How Do Puppies Get Parvo?

Parvo is one of the most common dog diseases in the world¹. It’s shed in poop so vast amounts of the virus can be harbored in very small amounts of poop from an infected dog. Puppies can become infected through their nose or mouth. Even though parvo is also spread in salvia, it isn’t an airborne disease. Puppies can be exposed through contact with another dog or contaminated poop, environments, or people.

Parvo is extremely hardy and can survive for several months outside an animal’s body. It’s unaffected by heat, cold, humidity, and drying². It’s also resistant to most household cleaning products. This combination of factors makes parvovirus easily transmitted from one environment to the next by hair, paws, people (unwashed hands, clothes, shoes), or objects (cages, bowls, bedding).

Locations such as dog parks and boarding or daycare facilities can increase your dog’s risk of infection since they are heavily trafficked by dogs and people.

During summer months and in warm or humid environments, infections are more common, but they can occur any time of year.

With their immature immune systems, puppies between six weeks and six months are most susceptible to infection. Older dogs can also be affected, especially if they’re unvaccinated or incompletely vaccinated.

Some breeds appear to be at an increased risk for parvo. These include³:

• American Pit Bull Terriers
• Doberman Pinschers
• English Springer Spaniels
• German Shepherds
• Rottweilers

How Does Parvovirus Cause Infection?

Following infection, it can take two to 14 days before symptoms are present. Once inside the puppy’s body, the virus invades rapidly dividing cells, such as those of the lymph nodes. It then spreads into the bloodstream, causing issues along the way until it reaches the small intestines.

Parvovirus then causes destruction of the lining of the intestines so the puppy can’t absorb nutrients, prevent fluid loss, and block bacteria from entering the body.

Generally, the infected puppy or dog is shedding the virus in their poop before symptoms develop³. This can start within four days of their first exposure, which is why highly trafficked dog areas can become contaminated easily without anyone realizing it until it’s too late. Dogs also spread the virus when they’re sick and for about 10 days after they have recovered.

What Are the Symptoms of Parvo in Puppies?

If your puppy or dog is exhibiting any of these symptoms, it is important to have them evaluated by your veterinarian immediately.

• Lethargy

• Lack of appetite

• Vomiting

• Diarrhea with or without blood

• Abdominal pain

• Bloated abdomen

• Fever

• Hypothermia (low body temperature)

Puppies, especially very young ones, can quickly dehydrate with continual vomiting and/or diarrhea. It can also cause damage to the intestinal tract and immune system, leading to septic shock, an infection of the bloodstream that can be fatal. Seek medical attention as soon as you notice your puppy is sick.

Most puppies who don’t make it will pass away within 48 to 72 hours following the start of symptoms⁴. Puppies have a 90% death rate if parvovirus is left untreated⁵.

What Is the Treatment for Parvovirus in Puppies?

Your veterinarian will diagnose your puppy with parvo based on their history, presenting symptoms, physical exam findings, and diagnostic tests.

Treatment includes providing supportive care, such as intravenous fluids, nutrient support, keeping them warm, and giving them medications to manage their symptoms.

If medical therapy is administered in a timely manner, as many as 86.6% of puppies recover⁴.

How to Prevent Parvo in Puppies

The best and easiest way to prevent parvo in your puppy is to get them properly vaccinated and maintain good hygiene practices.

Puppies obtain natural immunity from their mother’s milk, assuming they can nurse within 24 hours of birth. This immunity typically lasts for the first six to eight weeks of their life, leaving puppies vulnerable. They can become sick if exposed to parvovirus during this time until they develop active immunity from the vaccination.

A series of parvo vaccinations are recommended starting when the puppy is between 6-8 weeks until the puppy is about 20 weeks of age. This guarantees the puppy’s immune system is stimulated by the vaccine and protected against parvo.

It is recommended that puppies receive a parvovirus vaccine one year after their last vaccination in the introductory series and then every three years thereafter to help maintain their immunity⁵.

Since parvo is very hardy and can survive in the environment, it is important to use caution when taking puppies out, especially to high-traffic places like dog parks, pet stores, and boarding facilities, until they are fully vaccinated.

While walking your puppy, avoid contact with poop. But it’s important to note that most dogs get parvo from fomites, dogs or people contaminated with feces that isn't visible. So when you get home, leave your shoes outside or put them out of reach so your puppy can’t lick them. Be sure to wipe your puppy down, especially their paws, to remove any traces of fecal matter they may have picked up while walking.

The best prevention is to make sure your puppy is vaccinated and that you don’t miss their vaccine boosters every 3-4 weeks. Also, avoiding areas of possible contamination until your puppy is fully vaccinated is a good way to prevent them from picking up this virus. Until your puppy is fully vaccinated, avoid contact with any puppy or dog who has vomiting, diarrhea, or an unknown vaccination history. If you handle any dogs, change your clothes and wash your hands before handling your puppy.