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Both dogs and cats are susceptible to species-specific parvoviral infections. In either species, the virus causes a similar clinical syndrome, which is referred to as parvovirus in dogs and panleukopenia in cats. Signs may not occur until up to a week after infection. Unvaccinated/poorly vaccinated, very young and very old animals are at greatest risk. Pit Bulls, Labrador Retrievers, Doberman Pinschers and Rottweilers seem to be more susceptible to infection and may suffer more severe disease.

The character of the parvovirus is to destroy rapidly dividing cells. For this reason, the cells lining the intestinal tract and cells in the bone marrow, particularly white blood cells, are targeted. Because of this, clinical signs are primarily related to the gastrointestinal tract and from secondary infections that develop from bone marrow suppression.

The most common clinical signs are

  • vomiting and diarrhea, often hemorrhagic (containing blood)
  • lethargy
  • fever
  • decreased/absent appetite

A tentative diagnosis of parvoviral infection is based on the general history (i.e., exposure to other cats/dogs, coming from a crowded kennel situation, cattery etc.), vaccination history, clinical signs and supportive blood work findings. Blood work values indicating dehydration and low white blood cell counts (neutropenia) are most consistent. A definitive diagnosis is made based on a positive fecal ELISA test. The snap ELISA is the most commonly used test in private practices. It is made as a canine parvovirus test, but cross-reactivity with the feline parvo virus has been reported. Thus, it is used to test for panleukopenia in cats as well. The test is considered to be relatively sensitive, but false negatives can occur very early and late in infection. Vaccination does NOT interfere with this test.

Treatment of parvovirus and panleukopenia is supportive and symptomatic, meaning the patient is given the tools they need for their bodies to heal and recover. There is no definitive treatment for this viral infection. Aggressive intravenous fluids, antinausea medication, and broad-spectrum antibiotic therapy are key. A hospital stay of several days to a week should be expected. The trajectory of the disease can be a “roller coaster,” meaning that patients often will decline after admission to the hospital before they start to improve. They can have a life-long immunity following recovery from the hospital but still require annual vaccination. Once discharged from the hospital, the affected animal should be kept away from other animals of the same species for two weeks. The virus is hardy in the environment and the owner should bleach all surfaces possible, before another animal has contact with them.

The prognosis for affected dogs and cats is relatively good but is variable depending on the individual patient. Animals that are very young and/or develop sepsis (systemic infections) have a worse prognosis, especially if already in septic shock on presentation to the veterinarian. As mentioned above, several dog breeds may have a worse prognosis for unknown reasons. The key to a good prognosis is early presentation to the veterinarian, early diagnosis and aggressive supportive care for an adequate period of time.