Parvo in Dogs
Canine parvovirus (CPV), or parvo, is a highly contagious disease that causes severe, sometimes fatal illness, usually in unvaccinated puppies and dogs. Parvo primarily attacks the lining of the intestinal tract and the bone marrow. In very young puppies, the virus can also damage heart cells.
Dogs of any age can become infected with parvo, but puppies between the ages of six weeks and six months are most vulnerable to the disease.
Canine Parvovirus Symptoms
Common clinical signs of parvo are severe vomiting and diarrhea. Infected dogs often display lethargy, a lack of appetite, and fever, but not every dog with parvo will have exactly the same symptoms.
Here are the typical signs of parvo, which usually begin within three to seven days of infection:
- Lethargy
- Decreased appetite
- Fever
- Vomiting
- Diarrhea (sometimes containing blood)
- Weakness
- Dehydration (signs include dry gums, excessive drooling, and sunken eyes)
- Abdominal pain or bloating
In puppies, parvo may also cause these symptoms:
- High heart rate
- Difficulty breathing
- Low white blood cell (WBC) count
- Hyopthermia (low body temperature)
- Hypoglycemia (low blood sugar)
Parvo Transmission
Parvo is transmitted through direct contact with an infected dog or an infected dog’s feces. But parvo can survive for a year or more in the environment, so the live virus can persist even if fecal material itself is no longer visible. Unvaccinated dogs can be infected through contact with communal water bowls or any contaminated surface, such as grass, toys, shoes, or human hands.
Infected dogs can shed the virus in their stool for up to two weeks before they begin showing symptoms, and they continue to shed the virus for up to two weeks after their symptoms have resolved.
Stages of Parvo
Parvo has three stages: infection, incubation, and illness.
Infection
A dog becomes infected with parvo by ingesting the virus, usually through exposure to fecal material from an infected dog. Because the virus can survive for a long time in the environment, dogs can be infected through contact with contaminated soil or other surfaces: direct contact with another dog is not required.
Incubation
Once a dog has been infected with parvovirus, it typically takes three to seven days before symptoms appear. This interval after infection, but before symptoms appear, is called the incubation period.
During incubation, the virus seeks out the body’s most rapidly dividing cells, usually starting with the tonsils or the lymph nodes in the throat (both of which are part of the immune system). Targeting these rapidly dividing cells allows the virus to multiply quickly, enter the bloodstream, and spread throughout the dog’s body.
Illness
The virus typically does the most damage to the lining of the small intestine and the bone marrow. In young puppies, parvo can also damage heart cells.
In the bone marrow, parvovirus attacks young immune cells, weakening the immune system by reducing the number of protective white blood cells. With immune functions undermined, the virus can more easily invade the gastrointestinal (GI) tract.
In the GI tract, parvo attacks the lining of the small intestine. When this protective lining becomes damaged, the dog’s body has trouble absorbing important nutrients, particularly water. As a result, fluid is lost into the stool (causing diarrhea and dehydration), and bacteria that should remain in the intestines escape into the bloodstream (leading to infection).
If parvo attacks the heart, it can cause inflammation of the heart muscle and subsequently abnormal heart rhythms.
Because it causes such severe health issues, untreated parvo can lead to death within a few days. Dogs who don’t survive typically die from dehydration, shock (inadequate blood flow to the organs), and/or septicemia (infection caused by intestinal bacteria entering the bloodstream).
Testing for Parvo
Any puppy or unvaccinated adult dog suffering from vomiting and diarrhea should be tested for parvo.
With a small sample of your dog’s stool, your veterinarian (DVM) can perform an ELISA (enzyme-linked immunosorbent assay) test. This is a simple, inexpensive test that detects parvovirus antigens and gives results within minutes.
Your vet might also recommend blood work (including a white blood cell count), as well as X-rays or ultrasound of your dog’s abdomen.
Parvovirus Treatment
Dogs with parvo should be isolated (because the virus is so contagious) and hospitalized (because close monitoring is crucial).
Intensive care is especially important in the first few days that symptoms are present. A dog with parvo is at highest risk of death about 24–72 hours after they first show symptoms.
There is no cure for parvo, meaning that no treatment will kill the virus once it has infected a dog. Treatment for a dog with parvo consists mostly of supporting the immune system and compensating for the damage done by the virus while the body overcomes the infection.
Parvo breaks down the lining of the intestinal tract, causing it to become “leaky.” This allows fluid and bacteria from the intestines to escape into the rest of the body. The loss of water causes severe dehydration and electrolyte imbalance, and intestinal bacteria entering the bloodstream can lead to potentially fatal infection (septicemia). Parvo also weakens the immune system by reducing white blood cell numbers.
So parvovirus care typically starts with intravenous (IV) fluids to correct the dehydration and electrolyte imbalance. Antibiotics are given to prevent or control septicemia. Anti-nausea and antiemetic medications help reduce vomiting and limit further fluid loss. A dewormer can help if intestinal parasites are making a puppy’s diarrhea worse.
Nutritional support is also vital. A bland, easily digestible diet is recommended. Dogs with parvo who aren’t eating enough on their own may need a temporary feeding tube. Inserted through the nose, the tube allows nutrients to be administered directly into the esophagus or stomach.
If a dog’s blood glucose levels are too low, intravenous supplementation may be needed. In severe cases of parvo, a dog may require a plasma transfusion to replenish some blood elements.
Veterinary medicine offers some newer treatment options for parvo, including antiviral drugs, monoclonal antibody therapy, and fecal microbiota transplants (FMTs). These treatments would be given in addition to the standard care (not instead of it).
FMT for Parvovirus
The use of fecal microbiota transplants (FMTs) in puppies and dogs with parvo infections has been found to both reduce diarrhea and shorten hospitalization times. “FMT offers a promising way to restore the gut microbiome and support recovery in these fragile patients,” says Holly Ganz, PhD, AnimalBiome’s Chief Science Officer.
A fecal microbiota transplant is a procedure in which stool from a healthy donor—containing a complete and thriving community of healthy gut microbes—is transferred into the gastrointestinal tract of a recipient.
FMTs can be performed by several methods, such as by enema in a veterinarian’s office or by oral FMT capsules. Oral capsules, such as AnimalBiome’s Gut Restore Supplement for Dogs, are much less invasive and more affordable than other FMT procedures, and have been shown to be just as effective as the enema procedure.
A 2018 study published in the Journal of Veterinary Internal Medicine found that puppies with parvovirus who received an FMT recovered significantly faster than puppies who received only standard care (IV fluids, antiemetics, and antibiotics). Remarkably, 61% of the puppies who received an FMT had their diarrhea resolved in less than 48 hours, while less than 5% of the standard-care puppies got over their diarrhea that quickly. The study also found that the mortality rate among the puppies who received an FMT was lower (21%) than among those who received only standard care (36%), though this result was not statistically significant.
Our Gut Restore Supplement for Dogs offers a more affordable, less invasive FMT option that can be used both by veterinarians to treat parvo and by dog parents to restore the gut health of a dog who is recovering from a parvo infection.
Dr. Ganz and AnimalBiome have partnered with Jethro Forbes, DVM, DACVECC, and colleagues at Cornell University to investigate the benefit of FMT (Gut Restore) capsules in hospitalized patients with parvo. Their study compares patient outcomes when they receive FMT versus a placebo.
Learn more about how FMT capsules can help rebuild your dog’s gut health.
Parvo Recovery and Management
Left untreated, parvo has a survival rate of less than 10%. But in parvo puppies who receive plenty of supportive care—hospitalization, close monitoring, appropriate medications, intravenous fluids, and adequate nutrition—the survival rate is 85-95%. Beginning treatment as soon as the virus is detected greatly improves a dog’s chances of recovery.
Dogs who recover from parvo are usually sick for five to ten days after the first appearance of symptoms. Even after the symptoms have resolved, it’s important to keep the dog isolated, since they will continue to shed virus in their stool for two more weeks and could therefore infect other dogs.
The time it takes to recover from the disease will depend on the severity of the dog’s illness and the extent of the damage to their GI tract and immune system.
Parvo can affect the long-term health of a dog, leaving them more vulnerable to other problems in the future. One study found that puppies who survive a parvo infection are more likely to develop chronic gastrointestinal symptoms than dogs who were never infected with parvo.
Parvo Treatment Costs
Costs for treating a dog with parvo vary widely and depend on multiple factors, including the location of the hospital, the severity of the dog’s illness, the duration of hospitalization, and the terms of any applicable pet insurance.
Outpatient treatment could start at several hundred dollars. Costs for a severe case, including hospitalization for the average five to seven days, could be several thousand dollars. The average treatment cost is more than $5,000.
In contrast, vaccinating your puppy for parvo costs about $75 to $100 for three doses.
Prevention of Parvo in Dogs and Puppies
The best way to protect your puppy or young dog from parvo is to vaccinate them before they are exposed to the virus. The parvo vaccine is safe and highly effective. (It’s included in the DAPP vaccine, which protects puppies from distemper, adenovirus, parainfluenza, and parvovirus.)
Vaccine schedule
Puppies should receive a first dose of parvovirus vaccine at 8 weeks of age (or as early as 4 weeks in a shelter), with additional doses every 2–4 weeks until the age of 16–20 weeks. One year later, they should receive a booster shot. After that, a booster shot every one to three years is typically recommended for all dogs.
Vaccine failure
It’s possible, though not common, for fully vaccinated dogs to become infected with parvovirus. These instances of vaccine failure can occur for a number of reasons.
The most common reason for vaccine failure in puppies is interference from antibodies acquired from the mother dog. In addition, if the puppy is vaccinated at too young an age, their immune system may not be mature enough to respond properly to the vaccine. Because of these issues, the parvo vaccine is given in a series of doses, to help the puppy’s immune system “practice” fighting the virus.
The vaccine challenges a dog’s body to produce an appropriate immune response, so inadequate immune system health—because of malnutrition, heavy parasite burdens, or other illnesses—is another potential reason that vaccines fail.
Other reasons a vaccine can fail include:
- Breed predispositions (certain breeds, including Rottweilers and German Shepherds, seem more vulnerable to parvovirus than other breeds)
- Overwhelming exposure to the virus (e.g., in a crowded shelter environment with multiple infected dogs)
- Newer variants of the virus (viruses continuously evolve, and the immune system may not be prepared to deal with new variants)
Other protective measures
Until your puppy or dog is fully vaccinated against parvo, you should avoid places where the virus might be present (e.g., dog parks, pet stores). At home, you and any guests should remove your shoes at the door and wash your hands before interacting with your puppy.
Proper disinfecting of surfaces is crucial, but most household cleaning products will not kill parvovirus. Bleach (diluted in a 1:30 ratio with water) will kill the virus if left to soak for at least 10 minutes. (Remove any organic material from the surface first.)
Key Takeaways
- Canine parvovirus (CPV), or parvo, is a highly contagious disease that causes severe, sometimes fatal illness in puppies and dogs.
- Unvaccinated puppies from six weeks to six months of age are especially vulnerable to infection, but parvo can infect any dog, regardless of vaccination status.
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The most common clinical signs of parvo include vomiting, diarrhea, lethargy, reduced appetite, and dehydration.
- Parvovirus damages the lining of the small intestine, immune cells in the bone marrow, and (in very young puppies) the cells of the heart.
- After being infected by parvovirus, it takes three to seven days for a dog to show symptoms. In an infected dog who receives proper treatment, symptoms usually last for five to ten days. After symptoms have resolved, the dog is still contagious for two weeks.
- Parvo is transmitted through direct contact with an infected dog or their fecal material, or through indirect exposure—for example, via communal water bowls or contaminated grass.
- Parvovirus can survive in the environment for a year or longer, and most common cleaning products do not kill the virus.
- A quick, inexpensive test performed by a veterinarian can detect parvovirus in a sample of your dog’s stool
- There is no medication that kills parvo once it has infected a dog. For that reason, treatment involves supporting a dog’s key body functions as the dog’s immune system fights off the disease.
- A fecal microbiota transplant (FMT) can accelerate recovery by providing a complete set of healthy gut microbes.
- Left untreated, parvo has a fatality rate of about 90%. But with intensive care, most dogs can survive the disease.
- Vaccination is the best way to protect your puppy or dog from parvo. Puppies should receive a first dose of the parvo vaccine at about 8 weeks, with additional doses during puppyhood and regular boosters after that.
FAQ
Can humans get parvo?
No. The canine parvovirus is specific to dogs, so humans cannot get sick with parvo. However, humans can spread the virus from one dog to another if the virus gets on their hands or clothing. Before handling an unvaccinated puppy or dog, remove your shoes and wash your hands.
At what age is a puppy safe from parvo?
A puppy isn’t fully protected against parvo infection until they have received three doses of the vaccine. Puppies adhering to the recommended vaccine schedule are typically considered “fully vaccinated” by 16–20 weeks. One year later, they should receive a booster shot, with an additional booster shot every one to three years recommended for all dogs.
What are the first signs of parvo in a puppy?
The earliest sign of parvo to appear in puppies is often lethargy (lack of energy), followed by decreased appetite and vomiting. These symptoms quickly progress to diarrhea (often containing blood and mucus). Other signs in puppies may include fever, belly pain, low body temperature, high heart rate, and difficulty breathing.
Can I touch my puppy with parvo?
If you handle an infected puppy or dog, you can spread parvo to other dogs because the virus can survive for a long time on your hands and clothing. While you’re caring for your puppy with parvo, it’s best to isolate yourself from contact with any dogs who might not be fully vaccinated.
How is parvovirus diagnosed in dogs and puppies?
A veterinarian can run a quick, inexpensive test to detect parvovirus in a stool sample. Any puppy or unvaccinated dog suffering from vomiting and diarrhea should be tested for parvo.
Are there parvo tests?
The usual test for parvo is an ELISA (enzyme-linked immunosorbent assay) test, which detects parvovirus antigens in a dog’s stool sample. The test can be performed by a veterinarian and gives results in a few minutes.
How much does parvo treatment cost for dogs and puppies?
Treatment costs depend on many factors, including the severity of the dog’s illness, the length of hospitalization, and geographic location. Total costs for parvovirus care can range from several hundred to several thousand dollars.
Will a puppy with parvo survive?
Among puppies with parvo who receive plenty of supportive care—hospitalization, close monitoring, appropriate medications, intravenous fluids, and adequate nutrition—the survival rate is 85%–95%.