Parvovirus is one of the most common and potentially fatal dog diseases. It can be carried on your dog's hair and feet or on your shoes and clothing. While bleach kills it, sterile environments can quickly be reinfected. Parvovirus is preventable, but it kills 9 out of 10 dogs if left untreated.
If you are an experienced or new dog owner, you have probably heard the term parvovirus (or "parvo") bandied about. You may have even taken your dog to get his parvovirus vaccine. But what causes parvovirus in dogs, and what dog breeds are most at risk? What are the symptoms of canine parvovirus? How are dogs with parvovirus diagnosed, and can they be successfully treated? How long can a dog live with parvovirus, and does the disease cause any long-term side effects? How can parvo in dogs be prevented?
Here is everything you need to know about the causes, symptoms, treatment, and prevention of parvovirus in dogs.
Parvovirus is a highly contagious and potentially deadly disease in dogs that occurs throughout the world. It is caused by parvovirus strains called CPV-2a, CPV-2b, and CPV-2c.
Parvovirus attacks the cells that line a dog’s small intestine. The small intestine absorbs nutrients, water, and salt; it keeps the bacteria in his stomach from invading the rest of his body. By destroying the lining of the small intestine, parvovirus prevents the small intestine from properly functioning. As Baker Institute for Animal Health explains, "Eventually the intestinal surface can become so damaged that it begins to break down, and the bacteria that are normally confined to the gut penetrate the intestine walls and enter the bloodstream. This causes both significant fluid loss from diarrhea and widespread infection inside the body."
Parvovirus also targets your dog’s bone marrow and white blood cells. This causes his immune system to weaken and eventually shut down.
Parvovirus is most often spread when dogs eat or sniff infected poop. According to NCBI, this is because dogs shed "35 million viral particles (35,000 times the typical infectious dose)" in a single ounce of poop. For your reference, it only takes 1,000 viral particles for an unvaccinated dog to become infected with parvovirus. Parvovirus can be shed in dogs’ feces 3-6 weeks after they recover.
Parvovirus can be spread through direct contact with an infected dog or wild animal (e.g., coyotes, foxes, raccoons, and skunks). It also can be transmitted by indirect contact with a contaminated object (e.g., a harness, food or water bowl, or a toy).
Parvovirus can affect all dogs, but puppies that are under 4 months old have the highest risk. Unneutered male dogs are also twice as likely as unspayed females to develop the disease.
Unvaccinated dogs are 12.7 times more likely to be hospitalized with parvovirus. They are 3 times more likely to be admitted in July, August, or September, compared with the rest of the year.
American pit bull terriers, Doberman pinschers, English springer spaniels, German shepherds, Labrador retrievers, rottweilers, and Yorkshire terriers are also more susceptible to parvovirus.
According to the Center for Disease Control (CDC), pet dogs and cats cannot transit parvoviruses to humans. Dogs and cats are susceptible to several parvoviruses, but none of these cannot be transmitted to humans.
Humans are actually susceptible to their own parvovirus, Parvovirus B19. This virus is different than canine parvoviruses and cannot be transmitted to dogs or cats.
Signs and symptoms of canine parvovirus can appear within 2 to 14 days of infection. They can be mild or severe and include:
If your dog has any symptoms of parvovirus, please visit your vet as soon as possible. Consider calling them ahead of time, so they can plan to quarantine your puppy. This prevents him from infecting other dogs.
Parvovirus can cause your very young or unborn puppy’s heart to swell. Heart inflammation (also known as Myocarditis) does not cause any symptoms until it is severe enough to result in congestive heart failure. It can lead to sudden death within the first 8 weeks of life.
According to a 2018 study in PLoS ONE, dogs that survive parvovirus are also 5 times more likely to develop inflammatory bowel disease. It causes low-grade fever, vomiting, loose stools, tiredness, weight loss, and a poor-quality coat.
A fecal ELISA test is the most common test for canine parvovirus. ELISA stands for enzyme-linked immunosorbent assay. While it sounds complicated and high-tech, it is actually the same technology that is used for home pregnancy tests. In a fecal ELISA test, a microtiter plate that has 96 "wells" is coated with parvovirus antibodies. Then your dog’s poop is put in a microwell and sprayed with a color-changing chemical. If his poop changes colors, he has parvovirus.
A fecal ELISA test can be completed in your veterinarian’s office in less than 15 minutes. Though it is accurate 80% of the time, it occasionally produces false positive or negative results. For example, if your dog was recently vaccinated with a live vaccine (the type of vaccine that is most effective), it may produce a false positive.
Your veterinarian may also use a polymerase chain reaction test. It is the newest way to test for canine parvovirus. It requires your dog’s stool to be sent to a reference lab. The polymerase chain reaction test finds small pieces of parvovirus DNA in his poop and magnifies them. While it is 92.2% accurate, it can produce a false positive if your dog has been vaccinated for parvovirus or he is passing small amounts of virus.
Your veterinarian may also perform a simple blood test to measure your dog’s white blood cell count. Because parvovirus starts by attacking your dog’s bone marrow, a low white blood cell count could mean that he has the disease. If he has both a positive fecal ELISA test and a low white blood cell count, a fairly confident diagnosis of canine parvovirus may be made.
Most dogs with parvovirus are treated with injectable antibiotics, antacids, and anti-nausea meds. They are also given fluid therapy and nutritional support.
In severe cases, dogs with parvovirus may be given Neupogen, SEPTI-serum, a plasma transfusion, or a fecal transplant.
More than 90% of dogs that do not get treated for parvovirus will die within 48-72 hours. Dogs that are treated at home have a 50/50 chance of survival. According to a 2020 study in Animals, dogs that receive in-hospital care have an 86.6% survival rate. The average treatment time for parvovirus is 9.3 hours. Medical treatment increases life expectancy to 96.7% after 5 days.
Here is how to protect your dog from parvovirus:
If you have any questions or comments about canine parvovirus or want to share an experience with our dog-loving readers, please leave a comment below.
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