[Pseudotuberculosis caused by Yersinia pseudotuberculosis in a pet rabbit (Oryctolagus cuniculus)]

A 5-year-old dwarf rabbit (Oryctolagus cuniculus) with a body weight of 2.46 kg was presented due to acute inappetence, apathy, and diarrhea. The animal was housed outdoors with a companion rabbit in an enclosure with natural soil and an underground tunnel system. The general clinical examination revealed severe apathy, hypothermia (36.3°C), and increased abdominal respiration. Laboratory diagnostics showed a non-regenerative anemia as well as heterophilic and monocytic leukocytosis. Radiographic examination demonstrated hepatomegaly and loss of peritoneal detail. In addition to an enlargement of the liver and spleen, abdominal ultrasonography revealed multiple hypoechoic, round hepatic lesions, markedly enlarged mesenteric lymph nodes, and free fluid. Furthermore, several masses within the uterus and a focal renal infarction in the craniodorsal region of the right renal cortex were noted. Computed tomography confirmed the ultrasonographic findings and additionally showed generalized thickening of the large intestinal walls. Due to the poor general condition and the diagnostic findings, the animal was euthanized at the owner's request and submitted for pathological examination. The main findings included lymphadenomegaly of multiple intestinal lymph nodes and multifocal necrotizing inflammation of the spleen, liver, and bone marrow. Yersinia pseudotuberculosis was isolated from the spleen, leading to a diagnosis of pseudotuberculosis. This potential zoonosis has so far been documented in only one other case report in pet rabbits in the academic literature and should be considered a differential diagnosis in rabbits kept outdoors presenting with severe systemic disease.