The terminology associated with malignant lymphoma (lymphosarcoma) can be tricky. Leukemia simply means that a neoplastic proliferation of white blood cells is occurring in the peripheral blood and/or the bone marrow. It says nothing about the cell type (although the vast majority are lymphocytic leukemias), or the differentiation of the cells - immature neoplastic lymphocytes in the blood is called acute lymphocytic leukemia (ALL) and mature neoplastic lymphocytes is called chronic lymphocytic leukemia (CLL). The chronic forms of leukemia generally have a longer average lifespan. While feline leukemia is generally considered to be retroviral in origin, realize that there are spontaneous forms of non-viral leukemias in cats (which could also be called feline leukemias, if that name hadn't been subsumed for one particular disease. There has long been speculation and some good circumstantial evidence that some forms of ferret lymphoma are viral in origin, but it has not yet been conclusively proven. So the answer to your second question is an unqualified "maybe".... With kindest regards, Bruce Williams, DVM, DACVP Join the Ferret Health List at http://groups.yahoo.com/group/Ferret-Health-list [Posted in FML issue 3457]