Identification of a novel hemotropic mycoplasma in a splenectomized dog with hemic neoplasia

摘要

A 3-year-old sexually intact male Bull Mastiff was evaluated at the Veterinary Medical Teaching Hospital (VMTH) of the University of California because of a 10-day history of lethargy anorexia, poly-dipsia, vomiting, and melena and a history of markedweight loss during the preceding year. On evaluation by the referring veterinarian 2 days previously, the dog was febrile (rectal temperature, 39.8 deg C [103.6 deg C]); results of a CBC and serum biochemical analyses indicated normocytic, normochromic,nonregenerative anemia (Hct, 28%; reference range, 36% to 60%), leukocytosis (27,600 WBCs/uL; reference range, 4,000 to 15,500 WBCs/uL), neutrophilia (11,316 celis/uL; reference range, 2,060 to 10,600 cells/muL), mature lym-phocytosis (14,628 cells/muL;reference range, 690 to 4,500 cells/pi), monocytosis (1,380 cells/muL; reference range, 0 to 840 cells/muL), thrombocytopenia (73,000 platelets/muL; reference range, 170,000 to 400,000 platelets/muL), hyperbilirubinemia (1.6 mg/dL; reference range, 0.1to 0.3 mg/dL), hypoalbuminemia (1.8 g/dL; reference range, 2.7 to 4.4 g/dL), hypoproteine-mia (4.7 g/dL; reference range, 5.0 to 7.4 g/dL), and hypocholesterolemia (67 mg/dL; reference range, 92 to 324 mg/dL). Two days later, the dog had an episode of hematemesis and was reevaluated by the referring veterinarian. Mucosal pallor, icterus, splenomegaly, and tachycardia were detected on physical examination, and the dog was administered dexamethasone sodium phosphate (0.8 mg/kg [0.36 mg/lb], IV, once) andreceived an IV infusion of a crystalloid solution; pred-nisone was administered (0.5 mg/kg [0.23 mg/lb], PO, once). Cytologic evaluation of a bone marrow aspirate specimen revealed megakaryocytic hyperplasia and a mildly high myeloid-to-erythroid cell ratio. The dog developed profuse diarrhea with melena and was referred to the VMTH. The dog had no prior history of illness and no known tick exposure and had never traveled outside northern California There was 1 other dog in the household that appeared healthy.