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 hypergammaglobulinemia accompanied by minute vascular occlusions. The spontaneous lethal change in an individual appeared to arise during one of these hypergammaglobulinemic 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 transmission 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.