Canine Parvovirus, also known as parvo, is a highly contagious virus that affects young dogs. It is a common cause of acute GI illness and if left untreated can be fatal. Puppies and young adult dogs that have not been fully vaccinated are most at risk. The exact origin of parvo is unknown, but it is thought to be a variation of feline panleukopenia, which has a similar presentation as parvo but affects cats.
Parvo first emerged in the 1970s. During this time, dogs of all ages were affected because they had not been exposed to the virus. Later, a vaccine was created, and the incidence in vaccinated adult dogs was significantly reduced. Today, we are not seeing as many young dogs with parvo. This is most likely due to shelter vaccination programs, as well as pet owners being more educated on the importance of vaccinations. But the virus still exists, so you should be aware of some key points.
If you suspect your dog has parvovirus, contact your veterinarian as soon as possible and isolate them from other dogs because it is highly contagious.
What Is Canine Parvovirus?
Canine Parvovirus is shed in the feces of infected dogs within four to five days of exposure (often before clinical signs develop), throughout the period of illness, and up to two weeks after clinical recovery. Infection is acquired through direct oral or nasal contact with virus-containing feces or indirectly through contact with virus-contaminated inanimate objects (eg, environment, personnel, equipment). There is some evidence that parvo commonly affects dogs during the spring and summer months. Rottweilers, Doberman Pinschers, American Pit Bull Terriers, English Springer Spaniels, and German Shepherds have a higher frequency of occurrence.
Signs of Canine Parvovirus in Dogs
- Lack of Appetite
- Bloody Diarrhea
Clinical signs of canine parvovirus generally develop within five to seven days of exposure, but can be observed as early as two days and as late as 14. Initially, signs may include depression, lack of appetite, dehydration, and fever. These signs are pretty vague so can mimic other illnesses. As the condition worsens, vomiting and bloody diarrhea develop, usually within 24 to 48 hours. Physical exam findings by a veterinarian may include depression, fever or hypothermia (decreased body temperature), and abdominal pain which may be a sign of intussusception, an obstruction of the GI tract.
Severely affected dogs may present collapsed with prolonged capillary refill time, poor pulse quality, increased heart rate, and hypothermia. These signs are consistent with shock. When white blood cell counts are low and there is a breakdown of the intestinal barrier, bacterial toxins gain entrance into the body causing sepsis and eventually death. The mortality rate in puppies that are left untreated, may exceed 70 percent. Fortunately, the mortality rate in adult dogs is significantly lower, less than one percent.
How Is Canine Parvovirus Diagnosed?
Parvo should be suspected in any young dog that is exhibiting any of the above mentioned clinical signs, has not been properly vaccinated, and came from a shelter or breeding kennel. If you suspect your dog has been exposed to parvo, contact your veterinarian right away. They may start by running an in-house test that requires a small amount of fecal material. This test will detect the parvovirus in the feces and results are available in about 10 minutes. Although false-negative and false-positive results may be seen, this test is used as an initial diagnostic in an effort to begin isolation procedures, since this is an extremely contagious virus.
Additional tests include a complete blood count, a test that evaluates red and white blood cells. This test may show a moderate to severe low white blood cell count and blood loss. CBC monitoring can help the veterinarian gauge progress and assess prognosis. If improvement is seen within 24 hours of initiating treatment, the dog is likely to recover. Another test they will perform is a blood chemistry panel. This test will assess the major organ systems of the body like the kidneys and liver. Findings may include, elevations in kidney and liver enzyme levels, protein loss, hypoglycemia, and electrolyte imbalances.
Unfortunately, there is no cure for parvo. All hospitalized patients infected with parvo must be isolated due to its highly contagious nature. Treatment primarily involves aggressive supportive care which includes fluid therapy to correct dehydration, electrolyte, and metabolic imbalances; antibiotics for infection, anti-nausea medication, and nutritional support. Most cases of parvo require hospitalization, however, some patients may be considered for outpatient treatment once fluid and electrolyte balances are met.
How to Prevent and Control Canine Parvovirus
The key to the prevention of this potentially fatal virus is vaccination. If you have a young dog that is not fully vaccinated, it is crucial that you get them up to date on parvovirus and all recommended vaccines. Your veterinarian will provide you with a vaccine schedule. Puppies are typically given parvovirus boosters between six and 16 weeks of age at three- to four-week intervals. Young adults will receive the initial parvovirus vaccine and a booster in three to four weeks.
Dogs that have cleared the infection clinically, may still shed the virus in their feces for up to two weeks. Because parvovirus can remain viable in the environment for up to two months, disinfectants with oxidizing activity such as accelerated peroxide compounds or sodium hypochlorite, are recommended. These solutions must be prepared daily and applied after the removal of organic matter.
- Brooks, DVM, DABVP, Wendy. "Parvovirus In Dogs - Veterinary Partner - VIN". Veterinarypartner.Vin.Com, 2018, https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951463.
- Mitchell, D., Kelly, BSc, DVM, DVSc, DACVIM. "Canine Parvovirus - Digestive System - Veterinary Manual". Veterinary Manual, https://www.merckvetmanual.com/digestive-system/diseases-of-the-stomach-and-intestines-in-small-animals/canine-parvovirus.
- Kennedy, A., Melissa, DVM, PhD, DACVM and Adesola Odunayo, DVM, MS, DACVECC. "Canine Parvovirus". Cliniciansbrief.Com, 2017, https://www.cliniciansbrief.com/article/canine-parvovirus.