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Survival and outcomes in shelter cats with feline panleukopenia virus infection

Porporato F, Horzinek MC, Hofmann-Lehmann R, Ferri F, Gerardi G, et al. Survival estimates and outcome predictors for shelter cats with feline panleukopenia virus infection. J Am Vet Med Assoc. 2018 Jul 15;253(2):188-195.

Feline panleukopenia virus (FPV) is a serious infectious disease of domestic cats related (and ancestral) to canine parvovirus. Its causes damage to the bone marrow and intestines resulting in very low white blood cell counts and gastrointestinal disease. Mortality rates have varied between studies but are generally in the range of 50%. The disease in common in unvaccinated cat populations, as vaccination is very effective. As such, many outbreaks occur in shelter situations. While some data on prognostic indicators in FPV exist, the data is spare in this area and there is no data on the efficacy of individual therapies.

The purpose of this study was to determine prognostic factors for cats treated for clinical FPV infection. It was designed as a retrospective observational study. This study examined a group of cats infected with FPV during an outbreak lasting for 3 years in a large shelter in Northern Italy. Cats were enrolled in the study if they originated from the shelter, were treated only at the admitting hospital, had clinical sins of FPV and a positive parvovirus fecal ELISA.

177 cats were enrolled in the study, with a median age of 3 months (2m to 3y). 47.5% were male and 52.5% female. One cat was a Birman, the remainder were domestic shorthairs.

Results of admission and serial physical exam findings, bloodwork results, drug and therapy administration, and other factors were all logged. These were analyzed using both univariate and multivariate models.

Body weight at admission was found to correlate positively with survival (larger cats were more likely to survive). Cats above 37.9° C (100.22° F) were also more likely to survive than those below.

Leukopenia at admission had no effect on survival, contrary to previous findings. However, an increased total WBC count at 48h, 72h, and 7 days was associated with a higher rate of survival. No blood gas or biochemical variables were associated with survival.

Administration of amoxicillin-clavulanic acid had a positive effect on survival. No other antibiotic (ampicillin, cefazolin, ceftriaxone, and metronidazole) had any effect on survival, however they were not examined for use in combination.  The use of any antimicrobial (milbemycin oxime–praziquantel, fenbendazole, or imidacloprid-moxidectin) was associated with a higher rate of survival, however they were not examined individually. Maropitant was associated with a higher rate of survival. Metoclopramide, pain control, vitamins, fluid choice, nasogastric feedings, and use of blood products had no influence on survival.

The administration of recombinant feline interferon omega (IFN-Ω) was not found to have a positive or negative effect on survival. There was no association between the use of IFN-Ω and any other clinical findings.

Some flaws to this study exist. Though a standard protocol was followed, a prospective study would have allowed more careful control of variables than the retrospective model used. All cats were presumably infected with the same strain of virus, however virus from different global areas may respond differently to therapies. The survival rate in this study was 20%, lower than the previously described ~50%, suggesting there is some difference in viral strain or treatment protocol.

The authors conclude that several factors predict survival in cats with FPV, including: higher body weight, higher body temperature, deworming, use of amoxicillin-clavulanic acid, and use or maropitant. Factors linked to non-survival included use of a dextrose infusion (likely actually an indicator of hypoglycemia having a poor prognosis), and low leukocyte counts at days 3,4, and 7. Interestingly, the use of IFN-Ωhas no effect on survival. It is important to note that the findings of this study represent general trends any may not hold true for an individual patient, and as such should not dictate specific treatment protocols but rather provide a general guide to therapy.  (MRK)

See also:

Kruse BD, Unterer S, Horlacher K, et al. Prognostic factors in cats with feline panleukopenia. J Vet Intern Med 2010; 24:1271–1276.