Factors Influencing Outcome in Shelter Cats with Panleukopenia

Feline panleukopenia virus (FPV) is a highly contagious parvovirus that has an approximate fatality rate of 50%. Despite the commonality of the virus, little is known about the factors that predict survival. A recent study conducted in Italy evaluated various outcome predictors to better determine survival rate and timing of cats with naturally occurring feline panleukopenia in a shelter environment.

Study Design

This was a retrospective study of cats from a large feline shelter in northwestern Italy during an FPV outbreak that began in fall 2010 and continued for 3 years, at which time it was considered endemic. Medical records of FPV-positive cats admitted to the veterinary hospital of the Istituto Veterinario di Novara in Granozzo con Monticello, Italy, from January 1, 2011 to December 31, 2013 were reviewed.

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Cats were included in the study if they were positive for fecal-antigen enzyme-linked immunosorbent assay, originated from this shelter, had clinical and laboratory findings consistent with FPV, had complete records from presentation until recovery or death, and were treated for the duration of their illness only at this teaching hospital. Although retrospective, treatment protocols for FPV within this hospital were standardized and consistent among the patient population. Median survival was calculated, and numerous clinical and treatment variables were evaluated as potential prognostic predictors. Those that were statistically significant were then evaluated for independency.

Results and Discussion

One hundred seventy-seven cats met the inclusion criteria and were included in the study. Of these, 2 cats were vaccinated against calicivirus, feline herpesvirus, and FPV infection (these cats were 3 months old and had received only 2 vaccines in the series), 140 were unvaccinated, and 35 had unknown vaccination status. Of the 177 cats that started the study, 141 (79.7%) did not survive to discharge. Of these fatalities, 62 (44%) died within 2 days, and 117 (83%) died within 5 days. All 141 fatalities occurred within 15 days of hospital admission.

Several variables were independently associated with survival:

• Weight at hospital admission: For every 1-kg increase in body weight, the risk of death decreased by 41%.
• Lethargy: Ninety-one percent (59/65) cats with lethargy at hospital admission died.
• Rectal temperature: For every 1°C increase in rectal temperature at admission, risk of death decreased by 32%.
• Leukocyte count during hospitalization (but not at admission)

Leukocyte counts of survivors were significantly higher than those of nonsurvivors at 72 hours of hospitalization or beyond, but not before then. The following treatments were associated with a reduction in relative risk of death: amoxicillin-clavulanate (69% decrease), antiparasitic drugs (87% decrease), and maropitant (84% decrease). The only treatment associated with an increased risk of death was intravenous glucose (11-fold increase in risk of fatality). No other treatment variables were associated with outcome, including administration of feline recombinant interferon-w.

Clinical Impact

Survival rate in the present study was lower than previously published survival rates. Patients that are of low body weight, lethargic, or hypothermic (<37.9°C/100.2°F) at the time of hospital admission are more likely to be nonsurvivors. Leukopenia at or beyond 72 hours of hospitalization was associated with higher risk of death. Interestingly, leukopenia at admission or earlier in hospitalization was not associated with outcome. Treatment with amoxicillin-clavulanate, antiparasitics, and maropitant was associated with improved survival, but treatment with intravenous glucose was associated with a higher relative risk of death.

Dr. Packer is an associate professor of neurology/neurosurgery at Colorado State University College of Veterinary Medicine and Biomedical Sciences in Fort Collins, and is board certified in neurology by the American College of Veterinary Internal Medicine. She is active in clinical and didactic training of veterinary students and residents and has developed a comparative neuro-oncology research program at Colorado State University.