Relationships Between Severity of Histopathological Lesions of Aleutian Disease in Mink, Measured by Digital Image Analysis, and Antibody Titer and Serum Gamma-Globulin Level

Abstract

Aleutian disease (AD), caused by Aleutian mink disease virus (AMDV), is a serious problem for the multi-million-dollar mink industry in Nova Scotia. AD causes infiltration of mononuclear cells in various organs (plasmacytosis), high serum gamma-globulin levels and high anti-AMDV antibody titers, resulting in increased mortality and reduced reproduction rate. Selecting mink that can tolerate the infection is a viable way to control the problem. The first objective of this study was to develop a quantitative method of measuring the severity of histopathological lesions in the kidneys, liver and heart of AMDV-infected mink, using digital image analysis (DIA) software. The second objective was to assess relationships between the severity of AD lesions, assessed by DIA, and anti-AMDV antibody titer and serum gamma-globulin level, which are believed to be indicators of the severity of AD lesions in infected mink. A reproducible and reliable method was developed for the calculation of the percent infiltrated mononuclear cells on H&E stained slides of the kidneys, liver and heart of AMDV-infected mink. Associations between antibody titer and gamma-globulin level and percent infiltrated mononuclear cells measured by DIA software in the kidneys, liver and heart of 299 black mink, inoculated with a local strain of AMDV and monitored for up to 3.5 years, were generally weak, making the serological measures unreliable tools for the identification of tolerant mink, particularly when the time of infection is unknown.