DETERMINATION OF TIME OF ONSET AND LOCATION OF EARLY SKELETAL LESIONS IN YOUNG DOGS EXPERIMENTALLY INFECTED WITH HEPATOZOON AMERICANUM USING BONE SCINTIGRAPHY

Canine hepatozoonosis caused by Hepatozoon americanum has periosteal proliferation on long bones, pelvis, vertebrae, and skull. The pathogenesis of the periosteal proliferation is unknown but may be similar to hypertrophic osteopathy. Objectives were to determine the time frame for onset of bone lesions, to characterize spatial distribution of early bone lesions, and to describe the scintigraphic appearance of bone lesions in six immature dogs infected with 400 H. americanum oocysts on day 0. 99mTc-MDP bone scintigraphy was performed before and after infection. The onset bone lesions noted using scintigraphy was before day 35/36 in three dogs, day 46 in one dog, day 53 in one dog, and between days 46 and 67 in one dog. Early bone lesions primarily occur proximal to the carpus/tarsus and on the axial skeleton. Bone lesions were diffuse, bilaterally symmetric, homogenous, high intensity regions of radiopharmaceutical uptake.