Parvo Puppies

In the mid 1970s, canine parvovirus (CPV) emerged on the veterinary scene with the same ferocity that COVID-19 struck human medicine in the 2020s. By 1978, CPV was a worldwide epidemic, causing myocarditis in young puppies or severe gastroenteritis in older puppies and adult dogs, killing tens of thousands.

The Baker Institute of Animal Health at Cornell University's College of Veterinary Medicine has been at the forefront of research into viral diseases in animals for over 70 years. In 1978, researchers at the Baker Institute discovered that CPV is likely the result of 2 or 3 mutations of the closely related feline panleukopenia (FPV) virus. One of the diagnostic markers of both diseases is a very low white blood cell (WBC) count. The mutation that changed FPV to CPV allowed it to expand its host range from cats only to dogs. CPV can also infect wild canids like wolves and coyotes and other species like raccoons, foxes and skunks.

Research has shown that CPV is hardy and resistant to most environmental factors that readily kill weaker viruses like very hot or very cold temperatures and lack of humidity. It can also be tracked into people's yards and homes on paws or feet. Traditionally, bleach has been recommended as the only household cleaning product that affects CPV. Dilute bleach by adding 1/2 cup bleach to a gallon of water. This preparation deteriorates quickly and does not actually clean, so organic material must be removed first. It is effective against CPV if used on non-porous surfaces and left to sit for ten minutes. Drawbacks to using bleach are staining or bleaching of surfaces and caustic fumes.

A commercial disinfectant that uses an accelerated form of hydrogen peroxide called RESCUE is more effective at killing CPV and will clean surfaces also. It can be purchased from Amazon, Chewy or Walmart. Follow the label directions.

In the summer of 1978, veterinarians and pet owners began sending fecal samples to the Baker Institute. Over the next three years, researchers at Baker determined that CPV is a never-before-seen virus and went on to develop a diagnostic test and create a vaccine. We use Parvo SNAP tests in clinics to screen for CPV, which uses ELISA (enzyme linked immunosorbent assay) technology. Further confirmation can be obtained by sending a fecal sample to a referral lab for a more accurate PCR (polymerase chain reaction) test.

Effective vaccines against CPV are part of the routine vaccine protocols for all dogs now. To ensure adequate immunity from CPV, puppies need to be vaccinated every 3-4 weeks from the first vaccine at 6-8 weeks old to the last vaccine at 14-16 weeks old.

The Baker Institute continues to do research on CPV and other viruses that affect livestock and companion animals. Canine Parvovirus is devastating because it targets areas of the body where cells divide and grow rapidly. According to the researchers at Baker, CPV typically follows this path in the dog's body.

Once the dog ingests viral particles from sniffing, licking or eating in contaminated areas, the virus incubates in the tonsils and lymph nodes of the throat for 3-7 days. In the lymph nodes, the virus infects white blood cells called lymphocytes, replicating itself rapidly.

The infected lymphocytes start circulating in the bloodstream, targeting the fast growing cells of the bone marrow and the lining of the small intestine. This is where we usually start seeing symptoms like lethargy, unwillingness to eat, vomiting and diarrhea. When CPV attacks the bone marrow, it compromises the patient's ability to manufacture blood cells. WBCs are the immune system's first line of defense so if the numbers are low, the dog's body cannot defend itself from the virus. The infected lymphocytes will die off and not get replaced due to the bone marrow damage. This is what causes the low WBC count.

The epithelial lining of the small intestines helps the dog absorb nutrients, keeps fluid from leaking into the intestines and keeps gut bacteria from migrating into the body. CPV disrupts all this by damaging the lining's ability to replace old dying cells with fresh new cells. In very severe cases, the intestinal lining breaks down and begins to slough off. These patients often die of dehydration and septic shock despite aggressive treatment.

Less frequently seen and equally devastating, CPV causes myocarditis, inflammation of the heart muscle, in very young puppies. Some of these puppies die suddenly with no prior symptoms. Symptoms include difficulty breathing, coughing, lethargy, loss of appetite and weight loss. If it doesn't kill them, this can lead to poor heart performance and arrhythmias.

I hope that detailing the devastation CPV causes in your beloved dog's body, I have convinced you that vaccinating against CPV is the best treatment. A small percentage of vaccinated pets will still get parvo, 28% of puppies and 11% of adult dogs. Over the last few decades, treatment for CPV has become more effective, increasing the survivability rate to over 90%. There is no drug that kills the virus itself so treatment is supportive and symptomatic. Most of these pets spend 5-7 days in the hospital on IV fluid therapy and medications for vomiting and diarrhea. Because of the extended time in the hospital, treatment costs generally amount to several thousand dollars. Dogs who survive CPV have lifelong immunity.

For more details about CPV and the amazing work done at the Baker Institute for Animal Health, click here:

Vet.cornell.edu/departments-centers-and-institutes/baker-institute/our-research/canine-parvovirus