Abstract
Jembrana disease is an acute infectious disease of unknown etiology enzootic among Bali cattle (Bos javanicus) in Indonesia. Morphologic examination of 75 female Bali cattle between 18 months and 4 years old affected with Jembrana disease consistently revealed pulmonary granulomatous vascular lesions. The lesions were diffusely distributed throughout the lung. The principal lesion was the presence of a large number of intravascular macrophages that filled the lumina of pulmonary veins and pulmonary arteries of a vascular diameter of 20–200 μm, excluding the rest of blood cellular components. Concentric layers of perithelia] cells also with plasma cells and macrophages were occasionally present around both veins and arteries. Infiltration of polymorphonuclear leukocytes or small lymphocytes was not seen. Destruction or necrosis of tissues or blood vessels was rarely seen. Because this vascular lesion was found in the lungs of all affected cattle examined, this change is useful for the postmortem diagnosis of Jembrana disease. Moreover, its presence could be used to distinguish Jembrana disease from malignant catarrhal fever and other lymphoreticular proliferative conditions that are frequently found among cattle in Indonesia.