Marek\u27s Disease - Leukosis

During the past few years there have been many significant new findings concerning the avian leukosis complex. Until recently these diseases were termed visceral leukosis, neural leukosis, or avian lymphomatosis. Recent research work in England and this country has clarified the cause of these diseases and they can be divided into two distinct diseases. These two diseases now known as Marek\u27s disease and lymphoid leukosis, are caused by two different viruses. Today, the tumors and associated conditions caused by these diseases are the major disease problems of broiler and laying flocks. The loss in the United States from death and condemnation at the processing plant, is estimated to be in excess of 200 million dollars annually