Progression of Aleutian disease in natural and experimentally induced infections of mink.

OBJECTIVE: To study temporal changes in amounts of viral DNA in blood leukocytes over long periods, and to determine whether severity of the disease is greater in experimentally induced, compared with natural, infection. ANIMALS: 18 naturally and 6 experimentally infected black mink; 26 naturally infected brown mink. PROCEDURE: Polymerase chain reaction amplification to detect viral DNA in blood and counter-immune electrophoresis to detect serum antibody were performed at regular intervals. RESULTS: In naturally infected black mink, amounts of viral DNA were initially high, but after the appearance of antibody, viral DNA fluctuated and, in some instances, was undetectable. In other mink, small amounts of viral DNA were infrequently detected during the course of the infection. Amounts of viral DNA in leukocytes in late stages of the disease correlated with renal lesions in brown mink, but black mink had more severe lesions associated with smaller amounts of viral DNA. Severity of the disease was not enhanced in experimentally inoculated black mink. CONCLUSIONS: After infection, leukocyte viral DNA is initially present in large amounts, but, in most mink, decreases markedly in association with the appearance of antibody. There is no difference in the progression and severity of the disease between black mink infected experimentally or naturally. Transmission of the disease may be enhanced by use of contaminated toenail clippers for blood collection.