High molecular polymorphism of the hypervariable region in the VP2 gene of Aleutian mink disease virus

Parvoviruses exhibit extreme genetic plasticity. The VP2 protein, containing a hypervariable region, is of particular importance. A single nucleotide change in this part of the genome and its effect on the amino acid sequence may significantly affect the range of infected hosts, tropism for specific tissues, or virulence. The high polymorphism in the hypervariable region can be exploited for phylogenetic analysis. The aim of this study was to analyze the polymorphism of the VP2 hypervariable region in isolates of the Aleutian mink disease virus (AMDV) infecting Polish mink farms and to determine the phylogenetic relationships between the Polish isolates and genetic variants of the pathogen occurring in other countries. The study compares farms from two regions of Poland. The isolates contained five changes in the amino acid sequence, which had not previously been recorded in the NCBI database. There were 21 changes noted between the genotypes obtained and the sequence of the reference strain [GenBank NC_001662.1], of which 8 were in the hypervariable region. The isolates identified in our study exhibit a high degree of similarity within the farms, but between farms there is considerable variation in the amino acid sequence of the VP2 protein fragment. Because variants characteristic for farms were obtained, it will be possible to trace the movement of the virus between farms, and in the longer term to use the characteristic sequences as a marker of the origin of infected animals.