Abstract. Early detection of infection by the Aleutian mink disease virus (AMDV; Carnivore amdoparvovirus 1) by polymerase chain reaction (PCR) or counterimmunoelectrophoresis (CIEP) has important ramifications in virus eradication programs. A spleen homogenate containing a local isolate of AMDV was injected intraperitoneally into black (n = 44) and sapphire (n = 12) American mink (Neovison vison). Animals were euthanized 10 days postinoculation and anti-AMDV antibodies and AMDV DNA were tested in plasma and 7 organs by CIEP and PCR, respectively. Viral DNA was detected in the plasma, spleen, lymph nodes, bone marrow, and lung samples of all inoculated mink, but was not detected in some small intestine, kidney, and liver samples. In contrast, antibodies were detected in the plasma of 3 sapphire (25.0%) and 19 black (43.2%) mink but not in any of the organs. The sensitivity of the CIEP test on plasma samples was 39.3%, implying that low levels of antibodies during the early stages of virus exposure resulted in failure to detect infection by the CIEP test. We concluded that CIEP is not a reliable test for early detection of AMDV infection in mink and that there were considerable differences among mink of each color type for production of detectable levels of antibodies. PCR tests on samples of saliva, rectal swabs, and feces did not produce consistent and reliable results.

Background Selecting American mink (Neovison vison) for tolerance to Aleutian mink disease virus (AMDV) has gained popularity in recent years, but data on the outcomes of this activity are scant. The objectives of this study were to determine the long-term changes in viremia, seroconversion and survival in infected mink. Mink were inoculated intranasally with a local isolate of Aleutian mink disease virus (AMDV) over 4 years (n = 1742). The animals had been selected for tolerance to AMDV for more than 20 years (TG100) or were from herds free of AMDV (TG0). The progenies of TG100 and TG0, and their crosses with 25, 50 and 75% tolerance ancestry were also used. Blood samples were collected from each mink up to 14 times until 1211 days post-inoculation (dpi) and were tested for viremia by PCR and for anti-AMDV antibodies by counter-immunoelectrophoresis (CIEP). Viremia and CIEP status were not considered when selecting replacements. Low-performing animals were pelted and the presence of antibodies in their blood and antibody titer were measured by CIEP, and viremia and viral DNA in seven organs (n = 936) were tested by PCR. Results The peak incidences of viremia (66.7%) and seropositivity (93.5%) were at 35 dpi. The incidence of viremia decreased over time while the incidence of seroconversion increased. The least-squares means of the incidence of PCR positive of lymph node (0.743) and spleen (0.656) were significantly greater than those of bone marrow, liver, kidneys, lungs and small intestine (0.194 to 0.342). Differences in tolerant ancestry were significant for every trait measured. Incidences of viremia over time, terminal viremia, seropositivity over time, AMDV DNA in organs and antibody titer were highest in the susceptible groups (TG0 or TG25) and lowest in the tolerant groups (TG100 or TG75). Conclusion Previous history of selection for tolerance resulted in mink with reduced viral replication and antibody titer. Viremia had a negative effect and antibody production had a positive effect on survival and productivity.