The Nature of Aleutian Disease in Mink. I. Two Forms of Hypergammaglobulinemia as Related to Method of Disease Transmission and Type of Lesion

Aleutian mink disease is generally considered to precipitate spontaneously in ranch mink, with a lethal outcome. A two-year field study of a herd of susceptible mutant mink (sapphires and violets), however, has shown that all individual mink were affected from birth; the well state consisted of periodic low-level hypergamma-globulinemia accompanied by minute vascular occlusions. The spontaneous lethal change in an individual appeared to arise during one of these hypergammaglobu-linemic episodes and thus represented a failure of the immune system to control an inherent virus-induced mononucleosis. The fact that the entire herd was affected by the periodic form from birth is considered strong evidence for vertical trans-mission at a rate of 100%. The incidence of spontaneous precipitation was found to be dependent on the level of hypergammaglobulinemia in the mother during pregnancy. Aleutian mink disease (AMD) occurs in mink as a spontaneous degeneration with autoimmune disease-type nephritis, generalized plasmacytosis, splenomegaly, lymphadenopathy, and hypergam-maglobulinemia [1, 2]. Only a few brief studies of the normal levels ofy-globulin in serum of mink have been reported, although the hypergammaglobulinemia of the spontaneous, lethal form of AMD has received much attention. An opportunity to ex-amine these normal levels arose during observa-Received for publication December 15, 1975, and in revised form, March 8, 1976. Portions of this work were supported by a persona