Domestic Mink Research Articles

SARS-CoV-2 wildlife surveillance surrounding mink farms in British Columbia, Canada.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect many wild and domestic animal species. Farmed American mink (Neovison vison) are particularly susceptible to infection. Outbreaks of SARS-CoV-2 were detected in farmed mink on three mink farms in British Columbia (BC), Canada between December 2020 and May 2021. In BC, mink farm density and proximity to wildlife habitats increase transmission risks from infected farmed mink. The objective of this study is to investigate the risk of SARS-CoV-2 spreading to and from wildlife in the area surrounding infected mink farms in BC, Canada, as well as to compare the effectiveness of physical and camera trapping surveillance methodologies. A combination of physical and camera trapping was used on and around three BC mink farms with active SARS-CoV-2 infections between January 22, 2021, and July 10, 2021. Samples from trapped animals, including escaped farmed mink, were tested for SARS-CoV-2. Camera images from one mink farm were reviewed to determine species and proximity to the mink barn. Seventy-one animals of nine species were captured and sampled. Three captured mink tested positive for SARS-CoV-2 by polymerase chain reaction and serology; the remaining samples were negative for SARS-CoV-2. Genotyping of the three positive mink indicated these were domestic (vs. wild) mink. A total of 440 animals of 16 species were photographed at the one farm where cameras were deployed. Detection of SARS-CoV-2 in escaped farmed mink is concerning and demonstrates the potential for transmission from farmed mink to wildlife, particularly given the observation of wildlife known to be susceptible to SARS-CoV-2 near infected mink farms. Combined use of physical and camera trapping contributed to the breadth of the results and is strongly recommended for future surveillance.

Thinking Outside the Box: Utilizing Nontraditional Animal Models for COVID-19 Research

The ongoing COVID-19 pandemic continues to affect the lives, wellbeing, and stability of communities worldwide. The race to save human lives is critical, and the development of useful translational animal models to elucidate disease pathogenesis and prevention, and to test therapeutic interventions, is essential to this response. However, significant limitations exist with the currently employed animal models that slow our ability to respond to the pandemic. Non-human primates serve as an excellent animal model for SARS-CoV-2 disease and interventions, but the availability of these animals is scarce, and few facilities are able to house and utilize this model. Adapted murine models are accessible and improving but lack natural hACE-2 receptors and are only moderate representatives of human COVID-19 disease, transmission, and immune responses. On the other hand, there are several animal species that are both naturally and experimentally infected, such as domestic cats, hamsters, ferrets, and mink. Several of these have proven animal-to-animal transmission and evidence of significant clinical and histopathologic disease that mimics acute COVID-19 in humans. Mobilizing these nontraditional animal models could have a crucial role in SARS-CoV-2 research efficiency and impact. This review focuses on what is known about these nontraditional animal models, including their immune responses to SARS-CoV-2 infection, evidence of clinical and histopathologic disease, transmission potential, and the practicality of each model in a research setting. Comparative insight into these animal models for COVID-19 can strengthen the efforts to mitigate this pandemic.

148 Multiple Dysregulated Novel Pathways and Genes in Aleutian Mink Disease Revealed by Selection Signatures and Gene Network Analyses Using Whole-genome Sequence Data

Abstract Aleutian disease (AD) is a chronic persistent infection in domestic mink caused by Aleutian mink disease virus (AMDV). Female mink’s fertility and pelt quality depression are the main reasons for the AD’s negative economic impacts on the mink industry. A total number of 79 American mink from the Canadian Center for Fur Animal Research at Dalhousie University (Truro, NS, Canada) were classified based on the results of counter immunoelectrophoresis (CIEP) tests into two groups of positive (n = 48) and negative (n = 31). Whole-genome sequences comprising 4,176 scaffolds and 8,039,737 single nucleotide polymorphisms (SNPs) were used to trace the selection footprints for response to AMDV infection at the genome level. Window-based fixation index (Fst) and nucleotide diversity (θπ) statistics were estimated to compare positive and negative animals’ genomes. The overlapped top 1% genomic windows between two statistics were considered as potential regions underlying selection pressures. A total of 98 genomic regions harboring 33 candidate genes were detected as selective signals. Most of the identified genes were involved in the development and functions of immune system (PPP3CA, SMAP2, TNFRSF21, SKIL, and AKIRIN2), musculoskeletal system (COL9A2, PPP1R9A, ANK2, AKAP9, and STRIT1), nervous system (ASCL1, ZFP69B, SLC25A27, MCF2, and SLC7A14), reproductive system (CAMK2D, GJB7, SSMEM1, C6orf163), liver (PAH and DPYD), and lung (SLC35A1). Gene-expression network analysis showed the interactions among 27 identified genes. Moreover, pathway enrichment analysis of the constructed genes network revealed significant oxytocin (KEGG: hsa04921) and GnRH signaling (KEGG: hsa04912) pathways, which are likely to be impaired by AMDV leading to dams’ fecundity reduction. These results provided a perspective to the genetic architecture of response to AD in American mink and novel insight into the pathogenesis of AMDV.

An Opportunistic Survey Reveals an Unexpected Coronavirus Diversity Hotspot in North America.

In summer 2020, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was detected on mink farms in Utah. An interagency One Health response was initiated to assess the extent of the outbreak and included sampling animals from on or near affected mink farms and testing them for SARS-CoV-2 and non-SARS coronaviruses. Among the 365 animals sampled, including domestic cats, mink, rodents, raccoons, and skunks, 261 (72%) of the animals harbored at least one coronavirus. Among the samples that could be further characterized, 127 alphacoronaviruses and 88 betacoronaviruses (including 74 detections of SARS-CoV-2 in mink) were identified. Moreover, at least 10% (n = 27) of the coronavirus-positive animals were found to be co-infected with more than one coronavirus. Our findings indicate an unexpectedly high prevalence of coronavirus among the domestic and wild free-roaming animals tested on mink farms. These results raise the possibility that mink farms could be potential hot spots for future trans-species viral spillover and the emergence of new pandemic coronaviruses.

Impact of viral features, host jumps and phylogeography on the rapid evolution of Aleutian mink disease virus (AMDV)

Aleutian mink disease virus (AMDV) is one the most relevant pathogens of domestic mink, where it can cause significant economic losses, and wild species, which are considered a threat to mink farms. Despite their relevance, many aspects of the origin, evolution, and geographic and host spreading patterns of AMDV have never been investigated on a global scale using a comprehensive biostatistical approach. The present study, benefitting from a large dataset of sequences collected worldwide and several phylodynamic-based approaches, demonstrates the ancient origin of AMDV and its broad, unconstrained circulation from the initial intercontinental spread to the massive among-country circulation, especially within Europe, combined with local persistence and evolution. Clear expansion of the viral population size occurred over time until more effective control measures started to be applied. The role of frequent changes in epidemiological niches, including different hosts, in driving the high nucleotide and amino acid evolutionary rates was also explored by comparing the strengths of selective pressures acting on different populations. The obtained results suggest that the viral passage among locations and between wild and domesticated animals poses a double threat to farm profitability and animal welfare and health, which is particularly relevant for endangered species. Therefore, further efforts must be made to limit viral circulation and to refine our knowledge of factors enhancing AMDV spread, particularly at the wild-domestic interface.

Host Diversity and Potential Transmission Pathways of SARS-CoV-2 at the Human-Animal Interface.

Emerging infectious diseases present great risks to public health. The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), has become an urgent public health issue of global concern. It is speculated that the virus first emerged through a zoonotic spillover. Basic research studies have suggested that bats are likely the ancestral reservoir host. Nonetheless, the evolutionary history and host susceptibility of SARS-CoV-2 remains unclear as a multitude of animals has been proposed as potential intermediate or dead-end hosts. SARS-CoV-2 has been isolated from domestic animals, both companion and livestock, as well as in captive wildlife that were in close contact with human COVID-19 cases. Currently, domestic mink is the only known animal that is susceptible to a natural infection, develop severe illness, and can also transmit SARS-CoV-2 to other minks and humans. To improve foundational knowledge of SARS-CoV-2, we are conducting a synthesis review of its host diversity and transmission pathways. To mitigate this COVID-19 pandemic, we strongly advocate for a systems-oriented scientific approach that comprehensively evaluates the transmission of SARS-CoV-2 at the human and animal interface.

SARS-CoV-2 replicates in respiratory ex vivo organ cultures of domestic ruminant species

There is strong evidence that severe acute respiratory syndrome 2 virus (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19) pandemic, originated from an animal reservoir. However, the exact mechanisms of emergence, the host species involved, and the risk to domestic and agricultural animals are largely unknown. Some domestic animal species, including cats, ferrets, and minks, have been demonstrated to be susceptible to SARS-CoV-2 infection, while others, such as pigs and chickens, are not. Importantly, the susceptibility of ruminants to SARS-CoV-2 is unknown, even though they often live in close proximity to humans. We investigated the replication and tissue tropism of two different SARS-CoV-2 isolates in the respiratory tract of three farm animal species - cattle, sheep, and pigs - using respiratory ex vivo organ cultures (EVOCs). We demonstrate that the respiratory tissues of cattle and sheep, but not of pigs, sustain viral replication in vitro of both isolates and that SARS-CoV-2 is associated to ACE2-expressing cells of the respiratory tract of both ruminant species. Intriguingly, a SARS-CoV-2 isolate containing an amino acid substitution at site 614 of the spike protein (mutation D614G) replicated at higher magnitude in ex vivo tissues of both ruminant species, supporting previous results obtained using human cells. These results suggest that additional in vivo experiments involving several ruminant species are warranted to determine their potential role in the epidemiology of this virus.

Potential zoonotic sources of SARS-CoV-2 infections.

The severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) causing coronavirus disease‐2019 (COVID‐19) likely has evolutionary origins in other animals than humans based on genetically related viruses existing in rhinolophid bats and pangolins. Similar to other animal coronaviruses, SARS‐CoV‐2 contains a functional furin cleavage site in its spike protein, which may broaden the SARS‐CoV‐2 host range and affect pathogenesis. Whether ongoing zoonotic infections are possible in addition to efficient human‐to‐human transmission remains unclear. In contrast, human‐to‐animal transmission can occur based on evidence provided from natural and experimental settings. Carnivores, including domestic cats, ferrets and minks, appear to be particularly susceptible to SARS‐CoV‐2 in contrast to poultry and other animals reared as livestock such as cattle and swine. Epidemiologic evidence supported by genomic sequencing corroborated mink‐to‐human transmission events in farm settings. Airborne transmission of SARS‐CoV‐2 between experimentally infected cats additionally substantiates the possibility of cat‐to‐human transmission. To evaluate the COVID‐19 risk represented by domestic and farmed carnivores, experimental assessments should include surveillance and health assessment of domestic and farmed carnivores, characterization of the immune interplay between SARS‐CoV‐2 and carnivore coronaviruses, determination of the SARS‐CoV‐2 host range beyond carnivores and identification of human risk groups such as veterinarians and farm workers. Strategies to mitigate the risk of zoonotic SARS‐CoV‐2 infections may have to be developed in a One Health framework and non‐pharmaceutical interventions may have to consider free‐roaming animals and the animal farming industry.

Functional genetic diversity of domestic and wild American mink (Neovison vison).

The release of domestic organisms to the wild threatens biodiversity because the introduction of domestic genes through interbreeding can negatively impact wild conspecifics via outbreeding depression. In North America, farmed American mink (Neovison vison) frequently escape captivity, yet the impact of these events on functional genetic diversity of wild mink populations is unclear. We characterized domestic and wild mink in Ontario at 17 trinucleotide microsatellites located in functional genes thought to be associated with traits affected by domestication. We found low functional genetic diversity in both mink types, as only four of 17 genes were variable, yet allele frequencies varied widely between captive and wild populations. To determine whether allele frequencies of wild populations were affected by geographic location, we performed redundancy analysis and spatial analysis of principal components on three polymorphic loci (AR, ATN1 and IGF‐1). We found evidence to suggest domestic release events are affecting the functional genetic diversity of wild mink, as sPCA showed clear distinctions between wild individuals near mink farms and those located in areas without mink farms. This is further substantiated through RDA, where spatial location was associated with genetic variation of AR, ATN1 and IGF1.

Detection, genetic, and codon usage bias analyses of the VP2 gene of mink bocavirus.

Mink bocavirus 1 (MiBoV1), a novel virus detected from the feces of domestic minks in China in 2016, may be related to gastrointestinal diseases. However, its prevalence and genetic characteristics are poorly described. In this study, we examined 192 samples collected from minks in the major mink industry province from northern China. PCR results showed that 10 samples (5.2%) were positive for MiBoV1, and 60% of MiBoV1-positive samples were co-infected with Aleutian mink disease virus or mink circovirus. MiBoV1 was detected in six serum samples. Sequence analysis demonstrated that the VP2 gene of MiBoV1 was highly conserved and had low viral diversity over the VP2 region and unique nucleotide mutations. Phylogenetic analysis of the VP2 sequence demonstrated that MiBoV1 strains formed two clades and were grouped with California sea lion bocavirus, Canine bocavirus, and Feline bocavirus. Codon usage analysis revealed that most of the preferentially used codons in MiBoV1 were A- or U-ended codons, and no evident codon usage bias was found. This study provides evidence that MiBoV1 has a low prevalence in Jilin and Hebei provinces in China. Moreover, it contributes information regarding the expansion of the limited mink bocavirus sequence and determines the codon usage bias of the VP2 gene for the first time. Epidemiological surveillance is necessary to understand the importance and evolution of MiBoV1.

Hybridization of domestic mink with wild American mink (Neovison vison) in eastern Canada

Farmed American mink (Neovison vison (Schreber, 1777)) pose a risk to biodiversity owing to escape and release from farms. Feral mink may affect native species in locations where American mink are not endemic, such as Europe. In contrast, escaping domestic mink may hybridize with wild mink in North America, leading to introgression of domestic traits via hybrid-mediated gene flow. We tested this idea in eastern Canada, which has a history of mink farming. We sampled known domestic and free-ranging mink, and profiled 508 individuals at 15 microsatellite loci. We found that 33% of free-ranging mink were either escaped domestic individuals, domestic–wild hybrids, or were introgressed to domestic or wild parental groups. The greatest prevalence of free-ranging domestic, hybrid, or introgressed mink (59%) occurred in Nova Scotia, which also had the most mink farms. Historic (1980s or earlier) mink sampled from museums had higher allelic richness and private allelic richness than contemporary wild mink. Domestic mink are artificially selected for traits desired by farmers, and as such, introgression with wild mink may lead to a loss of local adaptation. Our findings demonstrate that continued escape and release of mink could pose risks to the maintenance of genetic integrity in wild mink.

Polymorphism of the American mink (Neovison vison (Schreber, 1777)) populations inhabiting the Caspian-Baltic watershed inferred by means of mtDNA D-loop

Analysis of the fragment of mtDNA D-loop (369 bp, n = 48) in wild and domestic American minks harvested in Caspian-Baltic watershed in the European part of Russia reveals a relatively high level of genetic polymorphism for introduced specimens. The values of haplotype and nucleotide polymorphism are correspondent to the level found in populations of the species inhabiting Eastern Europe (Poland). The tendency of differentiation of haplogroups is noted against the background of weak geographical or breeding structure of populations. Observed patterns of polymorphism are probably connected with peculiarities of introduction history as well as with the pool of initial DNA set of ancestors introduced in Eurasia. The domesticated form of the American mink does not differ from wild populations of the species on the basis of the used DNA marker. In wild populations of the species located at a short distance from a mink farm, haplotypes typical of domesticated minks are found.

Invasion and potential impacts of the first alien carnivore in China: American minks (<italic>Neovison vison</italic>) in Altai region, Xinjiang

American minks ( Neovison vison ), which cause great impacts on local small and median sized animals through direct predation and diseases tramission, had been characterized as an invasive species worldwide. As well-known fur animals, American minks were introduced to Europe in early 20th century, and to China in mid-20th century. American minks spread nearly entire Europe soon after escaping from fur farms in European countries, and they had already established naturalized population in northern Altai Mountain in Russia for years. Northern Altai Mountain is one of the main distribution areas of American minks in Russia. In recent years, American minks were reported in southern Altai mountains (Altai region, or Chinese Altai) in Xinjiang, China. American minks occurred in forest parks and national nature reserves in Altai region. Earlier records in China were misidentified as European minks or both of them. Based on field survey and photo identification, we confirmed that all these records were belong to American minks. Although American minks had been imported to China for over half a century, now they were found in wild in north-western China instead of eastern China, where had more mink farms. Thus American minks found in Chinese Altai may be border-crossing invaders. Through field survey and investigation, American minks were not rare in the forest parks and nature reserves of Chinese Altai region, thus we suggested that American mink had already established populations in China. We discussed the potential impacts of American minks invasion in China through habitat simulation, potential prey and competing species, and wildlife diseases. We discussed the current status of otters in China, which had similar niches to minks. Using MaxEnt model for habitats simulation at global scales, we predicted climate-suitable areas for American minks. We find that coastal regions of North America, south tip of South America, Europe, Eastern Asia, North Africa, South Eastern Australia and New Zealand harbor highly suitable habitats of American minks. All these coastal areas should be exceptionally precautious for live minks transport. In addition, mountains of Central Asia are the only inland highly suitable habitats of American minks. Central Asia harbors plentiful endemic fishes, and should be precautious for American minks invasion. In China, Chinese Altai and middle to lower reaches of Yangtze River are highly suitable habitats for American minks, where otters are almost disappeared. As China’s first alien carnivore, American minks will impose great predation pressures on endemic waterfowls and fishes, and will have impact on China’s endangered otters and other mustelids. All three major minks epidemic diseases: canine distemper, Aleutian disease and mink viral enteritis had already have outbreak records in Chinese mink farms, and theses diseases had been proven to transmit to wildlife. In addition, China the has largest mink farming industry of the world. Therefore, besides controlling border-crossing invasion, eco-security assessments should be strengthened in domestic mink farms.

Newcastle disease virus from domestic mink, China, 2014

Newcastle disease virus (NDV) is a pathogen that most often infects poultry species. In investigating a 2014 outbreak of encephalitis and death among farmed mink (Mustela vison), we found pathological and later experimental evidence that NDV can infect and cause severe encephalitic and pneumonic disease in these animals. Our findings confirm the host range of NDV.

Preliminary analysis of Psoroptes ovis transcriptome in different developmental stages.

BackgroundPsoroptic mange is a chronic, refractory, contagious and infectious disease mainly caused by the mange mite Psoroptes ovis, which can infect horses, sheep, buffaloes, rabbits, other domestic animals, deer, wild camels, foxes, minks, lemurs, alpacas, elks and other wild animals. Features of the disease include intense pruritus and dermatitis, depilation and hyperkeratosis, which ultimately result in emaciation or death caused by secondary bacterial infections. The infestation is usually transmitted by close contact between animals. Psoroptic mange is widespread in the world. In this paper, the transcriptome of P. ovis is described following sequencing and analysis of transcripts from samples of larvae (i.e. the Pso_L group) and nymphs and adults (i.e. the Pso_N_A group). The study describes differentially expressed genes (DEGs) and genes encoding allergens, which help understanding the biology of P. ovis and lay foundations for the development of vaccine antigens and drug target screening.MethodsThe transcriptome of P. ovis was assembled and analyzed using bioinformatic tools. The unigenes of P. ovis from each developmental stage and the unigenes differentially between developmental stages were compared with allergen protein sequences contained in the allergen database website to predict potential allergens.ResultsWe identified 38,836 unigenes, whose mean length was 825 bp. On the basis of sequence similarity with seven databases, a total of 17,366 unigenes were annotated. A total of 1,316 DEGs were identified, including 496 upregulated and 820 downregulated in the Pso_L group compared with the Pso_N_A group. We predicted 205 allergens genes in the two developmental stages similar to genes from other mites and ticks, of these, 14 were among the upregulated DEGs and 26 among the downregulated DEGs.ConclusionThis study provides a reference transcriptome of P. ovis in absence of a reference genome. The analysis of DEGs and putative allergen genes may lay the foundation for studies of functional genomics, immunity and gene expression profiles of this parasitic mite species.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1856-z) contains supplementary material, which is available to authorized users.

Selection for behavior and hemopoiesis in American mink (Neovison vison)

Abstract It has been known that selective breeding of animals for behavior associated with domestication changes a variety of physiological traits including response to stress and hypothalamo–pituitary–adrenocortical system activity. The aim of our research was to find association between behavioral type and differential leukocyte counts as an indicator of homeostasis activity. We used farm-raised 5-month-old minks ( Neovison vison ) that had been selective bred for 17 generations on the basis of behavior toward human. After selection, minks were divided into the following groups: aggressive (from −4 to −1), domestic (from +1 to +5). Blood leukocytes were analyzed in 5-month-old minks (n = 105) of different behavior lines: aggressive (−1, −2), domestic (+1 and from +3 to +5), fearful, and minks never subjected to selective breeding (control). We found strong effects of selection for behavior of minks on differential blood leukocyte count. There were differences between behavior types in differential leukocyte counts. Neutrophils and eosinophils were the leukocyte types the most sensitive to selection for behavior. The counts of eosinophils in peripheral blood in domestic (+3, +5) minks were higher than in control and aggressive (−2) minks. The percentage of neutrophils was higher in the most aggressive minks (−2) in comparison to domestic minks. We have concluded that differences found in leukocytes profile are the result of neuroendocrine system modification.

A novel bocavirus from domestic mink, China.

Bocaviruses have been found in the feces of humans and a variety of animals, including pigs, cattle, dogs, gorillas, cats, and sea lions. Here, we have characterized the almost complete genome (5224 nt) of a novel bocavirus from feces of domestic minks, which has been provisionally named mink bocavirus. The NS1 protein of mink bocavirus shared 36.9-52% amino acid sequence identities with those of other known bocaviruses and phylogenetically clustered with bocaviruses from other carnivores. According to the genetic distance-based criteria, mink bocavirus qualifies as a novel species of bocavirus. PCR of feces from a group of domestic minks, which included both healthy animals and animals suffering from diarrhea, revealed that 30% (9/30) shed virus. However, no association between viral shedding and the presence of diarrhea could be determined.

Beyond Rabies: Are Free-Ranging Skunks (Mephitis mephitis) in British Columbia Reservoirs of Emerging Infection?

Wild animal reservoirs are an important source of emerging and zoonotic infection. Skunks (Mephitis mephitis) are a reservoir of skunk strain rabies virus in Canada, with the exception of some areas including the province of British Columbia (BC). Beyond rabies, the reservoir status of skunks for emerging and zoonotic pathogens in BC is unknown. From March 2011 to February 2015, 50 free-ranging skunks were necropsied and tested for 4 pathogens: influenza A, Aleutian disease virus (ADV), Leptospira spp. and Salmonella spp. Two skunks (4%) with respiratory disease caused by influenza A (H1N1) pdm09 were detected during the human flu season suggesting that skunks may represent a target population for reverse zoonosis of this strain of influenza A virus. High prevalence of ADV infection was detected (43/50, 86%). Two of the infected skunks exhibited Aleutian disease (AD) suggesting that skunks act as both a reservoir and a target population for the virus. Most studies of ADV have focused on the potential for infection of free-ranging species living near mink farms. Our study suggests that urban skunks may be a primary host for the virus independent of domestic mink. Whether skunks act as a reservoir of ADV infection for other peridomestic species will depend on host specificity of the viral strains. Leptospira interrogans was detected in 18% (9/49) of the skunks. Identification of the serovar(s) detected is needed to determine any public health risk of leptospirosis following exposure to infected skunks. Salmonella spp. was isolated from three of 43 skunks (7%), specifically S. Typhimurium, S. Muenchen and S. Enteritidis. These serotypes cause disease in humans, but the low prevalence of infection suggests there is a low risk for zoonotic transmission.

Aleutian mink disease virus in striped skunks (Mephitis mephitis): evidence for cross-species spillover.

Aleutian mink disease virus (AMDV) causes a parvovirus infection, initially characterized in American mink (Neovison vison), that may have harmful effects on wild populations of susceptible animals. In North America, where American mink are native, the origin, host range, and prevalence of AMDV in wild species is not clear. We studied striped skunks (Mephitis mephitis) and raccoons (Procyon lotor) to determine whether species sympatric with mink are potential reservoirs in the transmission of AMDV to wild mink and mink farms. Antibodies to AMDV were detected in 41% of skunk serum samples (143/347) and AMDV nucleic acids were detected in 32% (14/40) of skunk spleen samples by PCR, indicating that AMDV exposure and infection were frequent in skunks. We detected no AMDV antibodies in 144 raccoon blood samples. Phylogenetic analysis revealed a newly identified AMDV haplogroup consisting of isolates from Ontario skunks and a free-ranging domestic mink from Ontario. Our findings of frequent AMDV infection in skunks, close genetic similarity between skunk and mink AMDV isolates, and evidence of AMDV transmission from skunks to mink support the hypothesis that skunks may be acting as alternative hosts and reservoirs of AMDV to wild mink through cross-species virus spillover.

Development of a nanoparticle-assisted PCR (nanoPCR) assay for detection of mink enteritis virus (MEV) and genetic characterization of the NS1 gene in four Chinese MEV strains.

BackgroundMink enteritis virus (MEV) causes mink viral enteritis, an acute and highly contagious disease whose symptoms include violent diarrhea, and which is characterized by high morbidity and mortality. Nanoparticle-assisted polymerase chain reaction (nanoPCR) is a recently developed technique for the rapid detection of bacterial and viral DNA. Here we describe a novel nanoPCR assay for the clinical detection and epidemiological characterization of MEV.ResultsThis assay is based upon primers specific for the conserved region of the MEV NS1 gene, which encodes nonstructural protein 1. Under optimized conditions, the MEV nanoPCR assay had a detection limit of 8.75 × 101 copies recombinant plasmids per reaction, compared with 8.75 × 103 copies for conventional PCR analysis. Moreover, of 246 clinical mink samples collected from five provinces in North-Eastern China, 50.8% were scored MEV positive by our nanoPCR assay, compared with 32.5% for conventional PCR. Furthermore no cross reactivity was observed for the nanoPCR assay with respect to related viruses, including canine distemper virus (CDV) and Aleutian mink disease parvovirus (AMDV). Phylogenetic analysis of four Chinese wild type MEV isolates using the nanoPCR assay indicated that they belonged to a small MEV clade, named “China type”, in the MEV/FPLV cluster, and were closely clustered in the same location.ConclusionsOur results indicate that the MEV China type clade is currently circulating in domestic minks in China. We anticipate that the nanoPCR assay we have described here will be useful for the detection and epidemiological and pathological characterization of MEV.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-014-0312-6) contains supplementary material, which is available to authorized users.