Specific humoral immunity in mink infected with the Aleutian disease virus (AMDV) and vaccinated against distemper

The Aleutian mink disease (AD) is one of the most serious threats to modern mink breeding. In farms where AD is endemic, a significant effect on breeding and reproductive effects is caused by permanent AMDV infection. The aim of this study was investigating the influence of subclinical infection of AMDV on the functional immune status and on the state of postvaccinal immunity against mink distemper. The analyses involved 30 brown mink females aged 12 weeks and allocated into an experimental group (group I) and control group (group II), with 15 animals in each. The minks from group I originated from the farm with an endemic form of Aleutian disease. The control minks from group II originated from the AMDV-uninfected farm. The dynamics of the growth of specific antibodies was examined after vaccination of the minks from both groups against distemper. Serum levels were determined in both groups with a seroneutralisation assay (SN). Obtaining positive values in the SN test in both groups of animals confirmed the induction of a specific immune response. There were significant differences in the magnitude of the positive SN assay values between the minks from group I and group II at all days of determination. The significantly lower SN values noted in the group minks with subclinical course of AMDV reveal that Aleutian disease can cause a suppressive effect on humoral response after vaccination.

Duplex PCR for Detection of Aleutian Disease Virus from Biological and Environmental Samples

Aleutian disease is one of the most serious disease entities affecting mink farms. The disease causes significant economic losses in mink breeding countries. The aim of the study was to optimize a diagnostic test based on duplex PCR to enable detection of Aleutian disease virus in biological and environmental samples. Blood (n = 40) and spleen (n = 40) samples from animals with suspected infection, and swabs from cages in which infected animals were kept (n = 20) were used for analysis. DNA was isolated from the samples, followed by optimization of the duplex PCR reaction targeting sequences coding NS1 and VP2 proteins. The qPCR method was used to determine the sensitivity of the reaction. The specificity of the analysis was confirmed by the sequencing results. Optimized duplex PCR enabled detection of Aleutian Mink Disease Virus (AMDV) genetic material in biological and environmental samples. Testing of the sensitivity of the method indicated clear amplification for both primer pairs at 102 copies of viral DNA in a reaction. Sequencing confirmed the specificity of the reaction, which in the case of both primer pairs indicated an over 90% agreement between the isolates and the variants of the virus from the databases. The use of duplex PCR to detect two regions of the AMDV genome may increase the sensitivity and specificity of the method and significantly expand the possibilities of further analysis based on sequencing.

Histopathologic and immunohistochemical lesions in liver of mink infected with Aleutian disease virus

Histopathologic and immunohistochemical lesions in liver of mink infected with Aleutian disease virus Parvovirus of Aleutian disease causes mainly damage to kidneys, but immune complexes deposition and damage may occur also in other organs. In mink farms of Latvia the liver dystrophy or hepatic lipidosis of mink is widely distributed. The goal of this study was to examine probability of liver damage and regeneration of mink infected with Aleutian disease virus. Liver injury was assessed histologically. The mink liver demonstrated inflammation of liver parenchyma and foci of fatty liver. In immunohistochemistry, during liver regeneration the matrix metalloproteinases MMP-9, vascular endothelial growth factor and β-defensin 2 expressions were lower, but MMP-2 and nerve growth factor receptor p75 expression was increased.