Feline panleukopenia: Analysis of possible survival biomarkers

Feline panleukopenia virus (FPV), also known as feline parvovirus, is a very common viral disease in cats, characterized by its high case fatality rate, for which the establishment of clear prognostic thresholds is complicated. The aim of this study was to evaluate the clinical relevance of different demographical, hematological, and biochemical variables and indexes obtained at hospital admission as potential prognostic factors for survival. A study was carried out of 58 cats diagnosed with FPV between 2017 and 2025 at the Veterinary Teaching Hospital of the University of Zaragoza. Variables analyzed included age, sex, hematocrit, counts of leukocytes, neutrophils, lymphocytes and platelets, neutrophil:lymphocyte ratio (NLR), platelet:lymphocyte ratio (PLR), albumin and potassium. The observed case fatality rate was 10.3% (6/58). No significant differences in survival were identified relative to age, sex, or the hematologic/biochemical indexes analyzed, although non-survivors tended to show lower hematocrit, albumin and neutrophil values together with relative lymphocytosis. These findings suggest that hematologic indexes such as NLR and PLR have limited utility in the feline species. Future studies with larger sample sizes and dynamic monitoring of biomarkers during hospitalization could clarify their true prognostic value. This work provides critical evidence on the limited usefulness of hematologic and biochemical indexes measured at admission as predictors of survival in cats with FPV, reinforcing the need for longitudinal studies and complementary parameters for better prognostic stratification.