Can plant toxicity accelerate mortality in a pet rabbit (Oryctolagus cuniculus) infected with Encephalitozoon cuniculi?

As grazing herbivores, pet rabbits are known to ingest household plants, some proven to cause intoxication. A previously healthy 2-year-old intact female rabbit was presented with inappetence that lasted about 12 hours. The rabbit was described as free-roaming and had been nibbling on leaves of a new plant over the last month. It was identified as the Madagascar dragon tree (Dracaena marginata), a saponin-containing plant, known to be toxic in other companion animals. Following a clinical examination, complete blood and urine analyses were performed, revealing azotemia and tubular proteinuria. Additionally, the rabbit tested positive for IgM and IgG antibodies against Encephalitozoon cuniculi. Ultrasonographic examination showed bilaterally enlarged kidneys with unclear demarcation of cortex and medulla, and a hyperechoic zone in the renal pelvis. The day after presentation, the patient died. The necropsy revealed petechial hemorrhages in the lungs, congestion of the spleen, and degenerative changes in the kidneys, liver, and heart. Histopathological examination of the kidneys indicated tubular necrosis and interstitial nephritis. Non-purulent encephalitis with perivascular infiltration of lymphocytes and histiocytes was also found. Based on the detected IgM and IgG antibodies against E. cuniculi, it is possible that the active infection contributed to the worsening of the patient?s health, with a consecutive death after prolonged ingestion of the toxic plant, or vice versa. Additionally, to the best of authors? knowledge, this is the first (laboratory) confirmed case of E. cuniculi infection in a pet rabbit in Serbia, which raises the awareness of the presence of this zoonotic pathogen.