T-CELL LYMPHOCYTIC LEUKEMIA IN A FALLOW DEER (DAMA DAMA)

A 17-yr-old female fallow deer presented with ataxia, inappetence, decreased fecal output, and decreased mentation. A complete blood count demonstrated leukocytosis (24.1×10(3)/μl, n=1.16-7.38×10(3)/μl), characterized by lymphocytosis (22.89×10(3)/μl, n=0.18-3.65×10(3)/μl), anemia (packed cell volume 20%, n=29.0-55.8%), decreased red blood cell count (4.1×10(3)/μl, n=6.86-14.72×10(3)/μl), and decreased hemoglobin (7.5 g/dl, n=9.4-19.2 g/dl). Numerous mature, well-differentiated lymphocytes were noted on the blood film. Despite treatment and clinical improvement, the decision was made to euthanize the deer. Histopathology identified a monomorphic population of CD3 positive, CD79a negative small lymphocytes replacing most of the hematopoietic tissue in the bone marrow without evidence of tissue invasion. Results of viral screening were negative.