Parvoviruses are small, single-stranded DNA viruses with non-enveloped capsids. Determining the capsid structures provides a framework for annotating regions important to the viral life cycle. Aleutian mink disease virus (AMDV), a pathogen in minks, and human parvovirus 4 (PARV4), infecting humans, are parvoviruses belonging to the genera Amdoparvovirus and Tetraparvovirus, respectively. While Aleutian mink disease caused by AMDV is a major threat to mink farming, no clear clinical manifestations have been established following infection with PARV4 in humans. Here, the capsid structures of AMDV and PARV4 were determined via cryo-electron microscopy at 2.37 and 3.12 Å resolutions, respectively. Despite low amino acid sequence identities (10-30%) both viruses share the icosahedral nature of parvovirus capsids, with 60 viral proteins (VPs) assembling the capsid via two-, three-, and five-fold symmetry VP-related interactions, but display major structural variabilities in the surface loops when the capsid structures are superposed onto other parvoviruses. The capsid structures of AMDV and PARV4 will add to current knowledge of the structural platform for parvoviruses and permit future functional annotation of these viruses, which will help in understanding their infection mechanisms at a molecular level for the development of diagnostics and therapeutics.

Aleutian mink disease virus (AMDV) is distributed widely among mink farms and wild mustelids despite ongoing attempts to stop the spread. The severity of Aleutian disease (AD) varies from subclinical to fatal but the reasons for its varying severity are complex and unclear. Recently, breeding of tolerant mink has drawn attention as the possible solution to reduce the effects of AD in farms. The aim of this study was to gather information on the effects of breeding based on overall health, production traits, and antibody titer on AD severity by comparing a positive farm (farm 1) that has been breeding for tolerance in mink to an infected farm without tolerance selection, and an AMDV-free farm. During the 2.5-year follow-up, the mink in farm 1 remained mostly free of clinical AD, had normal pelt quality and litter size, and had low virus copy numbers in tissues and low antibody titers in ELISA. In histopathological studies, most of the farm 1 mink had no/mild lesions in their kidneys. 29-43% of the mink were ELISA negative but PCR positive throughout the follow-up and frequent changes in virus strains and coinfections were observed. Several differences in gene expression between animals from different farms were also detected. These results indicate that the disease burden of AMDV can be reduced, with seemingly normal health and production rates, despite continual circulation of ADMV in cases where eradication attempts are unsuccessful.

Aleutian mink disease virus (AMDV) is known to cause the most significant disease in the mink industry. It is globally widespread and manifested as a deadly plasmacytosis and hyperglobulinemia. So far, measures to control the viral spread have been limited to manual serological testing for AMDV-positive mink. Further, due to the persistent nature of this virus, attempts to eradicate Aleutian disease (AD) have largely failed. Therefore, effective strategies to control the viral spread are of crucial importance for wildlife protection. One potentially key tool in the fight against this disease is by the immunization of mink against AMDV. Throughout many years, several researchers have tried to develop AMDV vaccines and demonstrated varying degrees of protection in mink by those vaccines. Despite these attempts, there are currently no vaccines available against AMDV, allowing the continuation of the spread of Aleutian disease. Herein, we summarize previous AMDV immunization attempts in mink as well as other preventative measures with the purpose to shed light on future studies designing such a potentially crucial preventative tool against Aleutian disease.

Aleutian mink disease virus (AMDV), which causes Aleutian disease, is widely spread both in farmed mink and wild mustelids. However, only limited data are available on the role of wild animals in AMDV transmission and spread. Our aim was to shed light on AMDV transmission among wild mustelids and estimate the effect of intense farming practices on the virus circulation by studying AMDV prevalence and genetic diversity among wild mustelids in Poland. We compared AMDV seroprevalence and proportion of PCR-positive individuals in American mink, polecats, otters, stone martens, and pine martens and used the phylogenetic analysis of the NS1 region to study transmission. In addition, we used a metagenomic approach to sequence complete AMDV genomes from tissue samples. In eastern Poland, AMDV seroprevalence in wild mustelids varied from 22 per cent in otters to 62 per cent and 64 per cent in stone martens and feral mink, respectively. All studied antibody-positive mink were also PCR positive, whereas only 10, 15, and 18 per cent of antibody-positive polecats, pine martens, and stone martens, respectively, were PCR positive, suggesting lower virus persistence among these animal species as compared to feral mink. In phylogenetic analysis, most sequences from feral mink formed region-specific clusters that have most likely emerged through multiple introductions of AMDV to feral mink population over decades. However, virus spread between regions was also observed. Virus sequences derived from farmed and wild animals formed separate subclusters in the phylogenetic tree, and no signs of recent virus transmission between farmed and wild animals were observed despite the frequent inflow of farmed mink escapees to wild populations. These results provide new information about the role of different mustelid species in AMDV transmission and about virus circulation among the wild mustelids. In addition, we pinpoint gaps of knowledge, where more studies are needed to achieve a comprehensive picture of AMDV transmission.

BACKGROUND: Aleutian mink disease virus (AMDV) causes major economic losses in fur-bearing animal production. The control of most AMDV outbreaks is complex due to the difficulties of establishing the source of infection based only on the available on-farm epidemiological data. In this sense, phylogenetic analysis of the strains present in a farm may help elucidate the origin of the infection and improve the control and biosecurity measures.
OBJECTIVE: This study had the following aims: characterize the AMDV strains from most outbreaks produced at Spanish farms between 2012-2019 at the molecular level, and assess the utility of the combined use of molecular and epidemiological data to track the possible routes of infection.
METHODS: Thirty-seven strains from 17 farms were partially sequenced for the NS1 and VP2 genes and analyzed phylogenetically with other strains described worldwide.
RESULTS: Spanish AMDV strains are clustered in four major clades that generally show a good geographical correlation, confirming that most had been established in Spain a long time ago. The combined study of phylogenetic results and epidemiological information of each farm suggests that most of the AMDV outbreaks since 2012 had been produced by within-farm reservoirs, while a few of them may have been due to the introduction of the virus through international trade.
CONCLUSIONS: The combination of phylogenetic inference, together with epidemiological data, helps assess the possible origin of AMDV infections in mink farms and improving the control and prevention of this disease.

Aleutian disease (AD), caused by Aleutian mink disease virus (AMDV), causes significant welfare problems to mink, and financial losses to the farmers. As there is no vaccine or treatment available, reliable diagnostics is important for disease control. Here, we set up a probe-based real-time PCR (NS1-probe-PCR) to detect all strains of AMDV. PCR was validated and compared to two other real-time PCR methods (pan-AMDV- and pan-AMDO-PCR) currently used for AMDV diagnostics in Finland. The NS1-probe-PCR had a similar detection limit of 20 copies/reaction based on plasmid dilution series, and similar or better diagnostic sensitivity, when evaluated using spleen samples from mink, and stool samples from mink and foxes. None of the three PCR tests cross-reacted with other parvoviruses. The NS1-probe-PCR also showed a significantly higher specificity than the pan-AMDO-PCR with spleen samples and the best specificity with stool samples. Furthermore, it produced the results more rapidly than the other two PCRs making it a promising tool for both diagnostic and research purposes.

The objective of this study was to develop a rapid, sensitive and specific EvaGreen (EG)-based real-time PCR assay capable of detecting Aleutian mink disease virus (AMDV) and to evaluate the reliability of the assay for analysis of blood or tissue samples. For this assay, a pair of primers was designed based on a nonstructural protein (NS)-encoding gene of AMDV, and the identity of PCR products was identified based on a melting temperature of 82.8°C. The EG-based real-time PCR assay did not detect canine distemper virus or mink enteritis virus, and the assay could be used to detect Chinese and American AMDV strains, in contrast to a commercial TaqMan kit that could only detect American AMDV strains. The amplification efficiencies of the EG assay were 104.8% for the Chinese strain and 94.4% for the American strain, and the detection limit was 1 copy/μL of AMDV plasmid or 3 pg/μL of viral DNA (Chinese strain). The intra- and inter-assay variation coefficients of melting temperature were all lower than 0.15%, confirming the high reproducibility of the assay. Forty-five clinical blood samples were simultaneously analyzed using the EG real-time PCR, TaqMan kit and conventional PCR, and the detection rates were 91.1%, 0.0% and 86.7%, respectively. Serum samples were also collected from the corresponding blood samples and tested using the counterimmunoelectrophoresis (CIEP) assay, where positive samples accounted for 24.4% of the 45 samples. In conclusion, EG-based real-time PCR is a rapid, sensitive, universal assay that can be effectively utilized as a reliable and specific tool for detection and quantitation of AMDV.

Aleutian mink disease virus (AMDV) is the causative agent of Aleutian disease (AD), which affects mink of all genotypes and also infects other mustelids such as ferrets, martens and badgers. Previous studies have investigated diversity in Finnish AMDV strains, but these studies have been restricted to small parts of the virus genome, and mostly from newly infected farms and free-ranging mustelids. Here, we investigated the diversity and evolution of Finnish AMDV strains by sequencing the complete coding sequences of 31 strains from mink originating from farms differing in their virus history, as well as from free-ranging mink. The data set was supplemented with partial genomes obtained from 26 strains. The sequences demonstrate that the Finnish AMDV strains have considerable diversity, and that the virus has been introduced to Finland in multiple events. Frequent recombination events were observed, as well as variation in the evolutionary rate in different parts of the genome and between different branches of the phylogenetic tree. Mink in the wild carry viruses with high intra-host diversity and are occasionally even co-infected by two different strains, suggesting that free-ranging mink tolerate chronic infections for extended periods of time. These findings highlight the need for further sampling to understand the mechanisms playing a role in the evolution and pathogenesis of AMDV.

OBJECTIVE: Aleutian Disease is a significant biological factor causing substantial losses in mink farming. The virus inducing the disease also infects wild populations which may constitute an asymptomatic reservoir. To compare genetic variants of the AMD virus occurring in wild and farmed mink populations, an analysis was performed on a fragment of the VP2 protein sequence of the virus infecting both populations, taken from different living environments.
METHODS: Genetic material was isolated from 11 farmed animals in which anti-AMDV antibodies had been detected and from 20 wild animals. The DNA obtained was amplified using primers specific for the fragment encoding the VP2 protein. The product obtained was sequenced and bioinformatic analysis was performed.
RESULTS: Viral material was detected in 11 farmed and 7 free-living animals. Similarity of sequences averaged 99% within groups and 94% between groups. The sequencing results made it possible to identify characteristic changes for each group. In the isolates from the wild animals, the following changes were observed in the epitope region with respect to the reference sequence: C3704T, G3710A, T3722C, T3746C and A3749G. In the isolates from the farmed animals a G3779A transition was noted. Phylogenetic analysis showed that the variants infecting the two groups occupy separate branches of the phylogenetic tree.
CONCLUSIONS: The variants of the virus infecting the two groups may have a common origin, but at present they constitute two separate groups, with characteristic differences making it possible to recognize their genotype.

Aleutian Mink Disease (AMD) is an infectious disease of mink (Neovison vison) and globally a major cause of economic losses in mink farming. The disease is caused by Aleutian Mink Disease Virus (AMDV) that belongs to the genus Amdoparvovirus within the Parvoviridae family. Several strains have been described with varying virulence and the severity of infection also depends on the host\'s genotype and immune status. Clinical signs include respiratory distress in kits and unthriftiness and low quality of the pelts. The infection can also be subclinical. Systematic control of AMDV in Danish mink farms was voluntarily initiated in 1976. Over recent decades the disease was mainly restricted to the very northern part of the country (Northern Jutland), with only sporadic outbreaks outside this region. Most of the viruses from this region have remained very closely related at the nucleotide level for decades. However, in 2015, several outbreaks of AMDV occurred at mink farms throughout Denmark, and the sources of these outbreaks were not known.
Partial NS1 gene sequencing, phylogenetic analyses data were utilized along with epidemiological to determine the origin of the outbreaks.
The phylogenetic analyses of partial NS1 gene sequences revealed that the outbreaks were caused by two different clusters of viruses that were clearly different from the strains found in Northern Jutland. These clusters had restricted geographical distribution, and the variation within the clusters was remarkably low. The outbreaks on Zealand were epidemiologically linked and a close sequence match was found to two virus sequences from Sweden. The other cluster of outbreaks restricted to Jutland and Funen were linked to three feed producers (FP) but secondary transmissions between farms in the same geographical area could not be excluded.
This study confirmed that partial NS1 sequencing can be used in outbreak tracking to determine major viral clusters of AMDV. Using this method, two new distinct AMDV clusters with low intra-cluster sequence diversity were identified, and epidemiological data helped to reveal possible ways of viral introduction into the affected herds.