Increased rectal temperature is associated with poor prognosis and infectious diagnoses in clinically ill pet rabbits

Objective: To determine whether an elevated rectal temperature is a predictor of survival in ill pet rabbits. Secondary aims were to identify risk factors associated with pyrexia in rabbits and to categorize the associated differential diagnoses. Methods: A retrospective cohort study was performed of 70 clinically ill pet rabbits treated at an exotics specialist hospital in Sydney, Australia, between 2018 and 2024. Thirty-five pyrexic rabbits (rectal temperature ≥ 40.0 °C) were temporally matched with 35 normothermic controls (38.0 to 39.9 °C). Data were collected with a systematic database search and included sex, neuter status, age, breed, rectal temperature, suspected diagnosis, and survival outcome. Rabbits lacking adequate follow-up were excluded. Logistic regression models analyzed associations between rectal temperature, survival, and risk factors. Results: Pyrexic rabbits were 1.27 (95% CI, 1.03 to 1.57) times more likely to die than normothermic rabbits and 4.52 (95% CI, 1.34 to 18.3) times more likely to have a poor outcome (euthanized or died). Each 1 °C increase in rectal temperature was associated with a 2.48-fold increase in chance of mortality (95% CI, 1.17 to 5.27). Neuter status was significantly associated with increased rectal temperature. Infectious disease accounted for 54.3% of pyrexia cases. Conclusions: Increased rectal temperature should be considered a significant finding when assessing the severity of illness and potential outcomes in clinically ill pet rabbits. Clinical Relevance: Rectal temperature measurement is a simple, accessible prognostic tool that can assist clinicians with triage, treatment planning, and client communication. Infectious disease should be prioritized as a differential diagnosis in rabbits with pyrexia.