Genomic characterization and phylogenetic analysis of Aleutian mink disease virus identified in a sudden death mink case

Aleutian mink disease (AMD) is one of the most serious diseases in minks worldwide, it brings tremendous financial losses in mink farming. AMD virus (AMDV) has unusually high genetic diversity, its genomic structure remains unclear. In 2014, sudden death of breeding minks was occurred in northeast China. After clinical signs evaluation and virus isolation, AMDV was identified in all sudden death minks, we investigated the complete genomic sequence of AMDV-LM isolated from the sudden death case. The full-genome sequence of AMDV-LM was 7 nucleotides (nts) or 8 nts longer than isolates AMDV-BJ and AMDV-G. AMDV-LM contained two unique nucleotide changes in VP2 (G79T, T710C), which led to two amino acid changes G27W and L237S. For NS1, some unique point mutations, such as A374C, A428C, A463C, and T476A were found and resulted in four unique amino acid mutations at N24V, H125P, V143P, K155Q, and V159N, respectively. The predicted secondary structure of the 5' terminal of AMDV-LM formed a large bubble formation near the 5' end, which affected the stability of the U-shaped hairpin. Phylogenetic analysis demonstrated that AMDV-LM was closely related to Chinese isolates and confirmed that AMDV strains circulating in China had different origins of ancestors. This study was first to investigate the association of sudden death of adult breeding minks with AMDV infection. Our findings provide useful suggestions for evaluation of the pathogenic potential of AMDV, additional details on AMDV genome characterization were also presented. Future work should focus on the importance of AMDV-LM strain in mink infection.