ABSTRACT
Jaagsiekte (JS), or ovine pulmonary adenomatosis, has been known as a disease entity for more than a century. Nevertheless, it remained an enigmatic condition until when its etiology was elucidated. The earliest reports concerning JS that have been traced emanated from the Cape of Good Hope during the early part of the 19th century. Even though JS was known to be an infectious disease long before its neoplastic nature was established in the 1920s, many years of painstaking research in various countries failed to reveal the etiological agent. Progress has been slow in the efforts to elucidate the pathobiology of JS. Since the discovery that a retrovirus causes the disease, attention has mainly been focused on the characterization of the virus and the elucidation of its relationship to other retroviruses.
