Leucoencephalopathy in Mink

In a herd of standard minks 30 cases of leucoencephalopathy were demonstrated in the mink kits in the years 1962 and 1963. The disease is assumed to be hereditary and due to a sub-lethal, recessive, autosomal factor. A comparison with the forms of diffuse sclerosis found in man demonstrated that the disease, as it appeared in minks, bore a striking resemblance to the so-called metachromatic type of leucoencephalopathy.     

Radiographic evaluation of destructive periodontal disease in blue mink in relation to age and blood morphology

In this study, blood samples and jaws were collected from 2 genotypes of blue mink (n = 289) in order to examine phenotypic expression of specific characteristics of Chediak-Higashi Syndrome (C-HS). Blood samples were subjected to differential counts to assess the proportion of abnormal polymorphonuclear leukocytes characteristic for CH-S (C-HS-leukocytes). Abnormal leukocytes with characteristic signs of C-HS were found in blood smears from all mink included in this study. Four teeth in one half of the mandible (P3, P4, M1, M2) were subjected to quantitative radiographic evaluation of alveolar bone loss and tooth loss. There was a high prevalence of destructive periodontal disease among blue mink included in this study. Mild to moderate periodontal disease (defined by less than 50% alveolar bone loss related to 1 or more teeth) affected 73.7% of young mink (age = 7 mo) and 67.9% of older animals (age > or = 19 mo). Severe periodontal disease (defined by more than 50% bone loss related to one or more teeth) was not detected in mink aged 7 mo, but affected 15.3% of mink aged 19 mo and 39.6% of mink aged 31 mo. The positive relationship between age and periodontal disease was statistically significant (P < 0.01). The prevalence of tooth loss was found to be high among blue mink aged > 19 mo (21.6%) and was also significantly related to age (P < 0.01). A significant positive interaction between alveolar bone loss and tooth loss (P < 0.01), implies that the highly prevalent tooth loss in the mink was related to and possibly caused by destructive periodontal disease. There was no significant difference in the prevalence of periodontal disease between the 2 genotypes and age was found to be the only statistical predictor of poor production results (P < 0.01) in blue mink.     

Comparison of the lesions of Aleutian disease in mink and hypergammaglobulinemia in ferrets.

Gross and microscopic lesions of Aleutian disease (AD) in mink and hypergammaglobulinemia in ferrets were compared. Both conditions were characterized by widespread proliferation of plasma cells, but proliferation was more prominent in mink infected with AD. Arteritis did not occur in hypergammaglobulinemic ferrets. Minimal or no glomerular alterations occurred in infected ferrets, but were severe in mink infected with AD. Bile duct proliferation was more prominent in diseased mink. Tissue alterations suggested that AD in Aleutian genotype mink is more rapidly progressive than is AD in ferrets, causing overt clinical disease and death. In contrast, hypergammaglobulinemia in ferrets appeared to progress more slowly, with little clinical evidence of disease. This is probably the result of a paucity of glomerular lesions in ferrets. Possible mechanisms to explain the differences in the development of lesions are discussed.     

Characteristics of inapparent Aleutian disease virus infection in mink.

Inapparent of nonprogressive Aleutian disease virus (ADV) infection is a subclinical but persistent virus infection of mink. Mink with the inapparent type of ADV infection when subjected to stress did not develop the progessive form of the disease. However, when challenged with a large dose of the virus, these mink did develop progressive Aleutian disease indicating that they were not highly resistant to the virus. Sera of mink with either the progressive of the inapparent type of ADV infection did not neutralise the virus. The anti-ADV antibody activity in mink with inapparent type of ADV infection was in the IgG fraction of the serum the same as in mink with progressive Aleutian disease. These data indicate that the resistance of the mink with inapparent infection as compared to mink with progressive Aleutian disease was not due to a difference in the class of immunoglobulin response to the virus. However, mink with progressive Aleutian disease showed a greatly increased immunoglobulin response.     

Studies on Viral Plasmacytosis (Aleutian Disease) of Mink : VII. Infection of Mink with DNA Extracted from Diseased Spleens

Lesions considered typical of aleutian disease developed in three of four mink inoculated with DNA extracted from spleens of mink with viral plasmacytosis. Control mink inoculated with buffered saline or DNA treated with specific enzyme (DNAase) remained normal. It is inferred that the infective DNA corresponds to viral DNA.

This DNA preparation was used in an attempt to infect tissue cultures from mink testis cells but the results were equivocal.

     

Detection of antibody in Aleutian disease of mink: comparison of enzyme-linked immunosorbent assay and counterimmunoelectrophoresis

Experiments were undertaken to investigate the potential of the enzyme-linked immunosorbent assay (ELISA) as a screening test for the diagnosis of the 2 known naturally occurring forms of Aleutian disease of mink. Anti-Aleutian disease virus (ADV) antibody activity was not detectable in the sera of mink with nonprogressive Aleutian disease despite the demonstration of antibody by counterimmunoelectrophoresis (CIEP) in the same sera. Anti-ADV antibody was detectable in 93% of sera from mink at various stages of experimentally induced progressive Aleutian disease. False-negative reactions occurred in sera which demonstrated high anti-ADV antibody titers by CIEP. As a consequence of the high prevalence of false-negative reactions, the ELISA was not considered to be an effective screening test. However, using CIEP as an indicator of ADV infection, the ELISA may be useful in differentiating mink with nonprogressive Aleutian disease from mink with progressive Aleutian disease.     

Transmission of Aleutian disease from mink with inapparent infections.

In apparent or nonprogressive Aleutian disease virus infection was considered a subclinical but persistent viral infection in which infected mink did not develop tissue lesions, hypergammaglobulinemia, or high antibody titers. Transmission of Aleutian disease virus from mink with this type of infection was measured. Mink with inapparent Aleutian disease appeared healthy and had normal gamma-globulin values, but were capable of transmitting the disease by direct and indirect horizontal contact. The risk of direct or indirect horizontal transmission from mink with inapparent infection was less than from mink with progressive Aleutian disease. Infection also was directly transmitted from the dam to the kits, but again the risk of infection from dams with inapparent infection was less than from dams with progressive Aleutian disease. Mink infected from their dams before weaning developed the disease more slowly than mink which became infected after weaning.     

Comparisons of feline panleukopenia virus, canine parvovirus, raccoon parvovirus, and mink enteritis virus and their pathogenicity for mink and ferrets

Parvoviruses from mink (mink enteritis virus [MEV]), cats (feline panleukopenia virus [FPV]), raccoons (raccoon parvovirus [RPV]), and dogs (canine parvovirus [CPV]) were compared. Restriction enzyme analysis of the viral replicative-form DNA revealed no consistent differences between FPV and RPV isolates, but CPV and MEV isolates could be distinguished readily from other virus types. Feline panleukopenia virus, RPV, and MEV, but not CPV, replicated to high titers in mink. However, on the first passage, disease and microscopic lesions were observed only in mink inoculated with MEV. Feline panleukopenia virus and RPV isolates replicated in ferrets, but disease or microscopic lesions were not observed. Feline panleukopenia virus and RPV isolates could be passaged repeatedly in mink and ferrets. Virulence of FPV and RPV isolates was low compared with that of MEV, and only a single mink inoculated with FPV or with RPV developed clinical disease on the sixth passage of virus.     

Studies on influenza viruses H10N4 and H10N7 of avian origin in mink

An influenza A virus, A/mink/Sweden/84 (H10N4), was isolated from farmed mink during an outbreak of respiratory disease, histopathologically characterised by severe interstitial pneumonia. The virus was shown to be of recent avian origin and closely related to concomitantly circulating avian influenza virus. Serological investigations were used to link the isolated virus to the herds involved in the disease outbreak. Experimental infection of adult mink with the virus isolate from the disease outbreak reproduced the disease signs and pathological lesions observed in the field cases. The mink influenza virus also induced an antibody response and spread between mink by contact. The same pathogenesis in mink was observed for two avian influenza viruses of the H10N4 subtype, circulating in the avian population. When mink were infected with the prototype avian H10 influenza virus, A/chicken/Germany/N/49, H10N7, the animals responded with antibody production and mild pulmonary lesions but neither disease signs nor contact infections were observed. Detailed studies, including demonstration of viral antigen in situ by immunohistochemistry, of the sequential development of pathological lesions in the mink airways after aerosol exposure to H10N4 or H10N7 revealed that the infections progress very similarly during the first 24h, but are distinctly different at later stages. The conclusion drawn is that A/mink/Sweden/84, but not A/chicken/Germany/N/49, produces a multiple-cycle replication in mink airways. Since the viral distribution and pathological lesions are very similar during the initial stages of infection we suggest that the two viruses differ in their abilities to replicate and spread within the mink tissues, but that their capacities for viral adherence and entry into mink epithelial cells are comparable.     

Immunohistochemical detection of 3 viral infections in paraffin-embedded tissue from mink (Mustela vison): a tissue-microarray-based study

Immunohistochemical (IHC) assays were developed and tested for the detection of 3 viral infections in archived paraffin-embedded mink tissue. Specimens had been obtained from mink with diagnoses of acute Aleutian disease (AD), mink parvoviral enteritis (MVE), or canine distemper (CD) made by means of routine diagnostic procedures. To improve the efficiency and reduce the costs of IHC analyses, tissue microarray (TMA) technology was used. Representative cores 2 mm in diameter from each tissue specimen and from positive- and negative-control specimens were collected in a TMA block. Immunohistochemical reactions to viral antigens were assessed and graded. Positive reactions were found in 91% of the 32 specimens from mink with AD, 53% to 80% of the 60 specimens from mink with MVE, and all 66 of the specimens from mink with CD. To validate the use of TMAs, the IHC methods were applied to whole-mount paraffin-embedded sections of 10 of the positive specimens for each disease, together with whole-mount sections of small intestine and lung tissue from 2 healthy mink. The IHC grading of the TMA cores and the whole-mount sections from the same animal corresponded completely. These results suggest that IHC demonstration of viral antigen allows rapid and reliable diagnosis of the 3 viral infections in mink and is a potential supplement to histologic diagnostic procedures. The TMA technique proved useful for screening large numbers of samples for expression of specific viral antigens, while reducing overall costs.     

水貂阿留申病毒的分子生物学研究进展

从水貂阿留申病毒(ADV)基因组特点出发,就阿留申病毒的分子生物学研究进展作以简单综述。     

Effect of infectious dose and season on development of hemorrhagic pneumonia in mink caused by Pseudomonas aeruginosa

Hemorrhagic pneumonia is an acute and fatal disease of farmed mink caused by Pseudomonas aeruginosa. The pathogenesis of this disease has not yet been resolved. Mink are the only animals known to be susceptible to acute, contagious, and fatal lung infections caused by P. aeruginosa. The purpose of this study was to investigate the correlation between dose-response and season of infection and to clarify whether Danish mink are carriers of P. aeruginosa on their nasal mucosa during the season for hemorrhagic pneumonia. To elucidate the pathogenesis of the disease, an infectious dose-response trial was carried out on adult mink and mink kits, both in the season for hemorrhagic pneumonia (November) as well as out of season (July). It proved difficult to infect mink via the intra-nasal route. Only 4 out of 60 infected mink developed clinical disease and were euthanized, all of them in November, illustrating that predisposing factors in the mink itself and not infectious dose might be crucial for disease development. We were able to culture P. aeruginosa from the nasal cavity of the clinically healthy experimental mink 8 d after inoculation. This indicated that the mink can carry P. aeruginosa on their nasal mucosa without developing the disease. It was not possible, however, to culture P. aeruginosa from the nasal cavity of clinically healthy mink obtained from farms in November, which indicates that the organism is not a normal part of the nasal mucosal flora of mink.     

貂犬瘟热病的诊断

貂犬瘟热是危害貂、狐、貉最严重的烈性传染病之一。作者对某貂养殖场的病死貂进行临床症状观察,病理剖检及实验室诊断,通过病毒的分离培养及鉴定,确诊病死貂为貂犬瘟热病毒感染。鉴于养殖场中该病的存在及对养貂业的危害,建议加强对貂犬瘟热病的诊断及监控。     

Effect of a valine residue at codon 352 of the VP2 capsid protein on in vivo replication and pathogenesis of Aleutian disease parvovirus in mink

OBJECTIVE: To determine whether a group of 3 genetic differences in the nonstructural protein (NS1) or 1 genetic difference in the structural protein (VP2) of Aleutian disease parvovirus (ADV) is responsible for an increase in the in vivo replication and pathogenicity of G/U-8, a chimera of ADV-G (nonpathogenic) and ADV-Utah (pathogenic), compared with G/U-10. ANIMALS: 32 eight-month-old female sapphire mink (Mustela vison). PROCEDURE: Chimeric viruses were constructed, propagated in vitro, and used to inoculate mink. Antiviral antibody responses, presence of serum viral nucleic acid, and serum gamma globulin concentrations were monitored for 120 days following inoculation. Histologic examination of the liver, kidneys, spleen, and mesenteric lymph nodes was performed after necropsy. RESULTS: A chimera containing only the 3 amino acid substitutions in NS1 did not elicit measurable responses indicative of replication or pathogenicity in inoculated mink. Serum antiviral antibody responses, frequency of detection of viral nucleic acid in serum, gamma globulin response, and histologic changes in mink inoculated with chimeras containing a valine residue at codon 352 (352V) of VP2 capsid were increased, compared with values from mink inoculated with chimeric viruses that did not contain 352V. CONCLUSIONS AND CLINICAL RELEVANCE: A valine residue at codon 352 in the VP2 capsid protein of ADV affects in vivo viral replication and pathogenicity. This amino acid may be part of an incompletely defined pathogenic determinant of ADV. Further characterization of the pathogenic determinant may allow future development of focused preventive and therapeutic interventions for Aleutian disease of mink.     

水貂阿留申病的历史回顾及最新研究概述

水貂阿留申病是阻碍养貂业发展的世界性攻关病害。自人们发现该病至今已有５０余年的历史，尽管国内外有关专家学者，从没间断过对该病的研究，但始终没能攻克该病的免疫防制问题；值得庆幸的是，在国家科委和农业部畜牧兽医司等部门的大力资助下，我们对阿留申病的免疫原性和免疫机制进行了较系统深入的研究，并研制出了阿留申病灭活疫苗，现已在多个大型貂场进行小试。该文对阿留申病的病史和危害，以及最新研究进展和重大技术突破进行了较全面系统的论述。     

A survey of Aleutian mink disease virus infection of feral American mink in Nova Scotia

Spleen samples from 14 mink that were trapped in 4 counties of Nova Scotia were tested for the presence of the Aleutian mink disease virus (AMDV) by polymerase chain reaction. Viral DNA was not detected in samples from Kings County (n = 2), but was detected in all the mink sampled from Colchester (n = 2) and Halifax (n = 6) counties, and 3 of 4 mink from Yarmouth County. The high level of AMDV-infected mink in Colchester and Halifax counties may pose a serious threat to the captive mink and wild animal populations. Because treatment of infected free-ranging mink is not an option, AMDV control strategies for the captive mink should be primarily focused on bio-security to protect clean ranches.     

水貂阿留申病的研究进展

水貂阿留申病(Aleutian disease of mink,ADM)是由水貂阿留申病细小病毒(Aleutian mink disease parvovirus,AD-MV)引起的一种慢性、进行性传染病,一直是危害世界养貂业健康发展最重要的疫病之一。到目前为止,还没有疫苗可成功用于ADM的预防,也没有特异有效的治疗方法,唯一可行的防治方法就是通过多次特异性检疫,淘汰病貂,净化貂群。笔者对阿留申病的病原学、发病机制、防治措施等方面进行概述,为临床防治水貂阿留申病提供了理论基础。     

Detection of Aleutian disease antibodies in feral American mink in southern England.

Fourteen of 27 American mink (Mustela vison) trapped in the upper Thames region were positive for anti-Aleutian disease antibodies. This demonstration of the occurrence of this viral disease in a feral American mink population suggests that it could threaten populations of at least two protected mustelids, the otter (Lutra lutra) and the polecat (Mustela putorius), and may also play a role in the apparent decline of local mink populations in Britain.     

Mink with Aleutian disease have autoantibodies to some autoantigens

Thirty mink infected with Aleutian disease virus (ADV) were found to have elevated levels of antibody to double-stranded DNA (dsDNA) in their sera when compared to 30 healthy mink. The anti-dsDNA antibody levels in the diseased mink were, however, not found to correlate with the total amount of immunoglobulin. This was a common observation for all autoantibodies tested. The concentration of rheumatoid factors of IgG class, but not those of IgM class, was found to be significantly higher in the diseased mink at the chosen level of significance (P less than 0.01). IgG antibodies to thyroglobulin were likewise significantly higher in the ADV-infected mink. Unexpectedly, we found IgG antibodies with specificities for cardiolipin and mitochondrial antigens to be significantly higher in healthy mink than in ADV-infected mink. This difference is especially remarkable since the serum immunoglobulin concentration of the ADV-infected mink was three times higher than the serum immunoglobulin concentration of the normal mink.     

应用RAMP标记分析水貂与彩貂种属间的遗传多样性

对标准黑褐色水貂、蓝宝石貂、咖啡色貂3个品种的89个个体进行了RAMP分析。结果表明,品种间遗传差异明显,多态性高。14个引物组合扩增出的81条DNA片段中,75条具有多态性,多态比例为92.59%,每个引物组合可扩增4～8条多态性条带,平均5.78条。多态条带比率、Shannon多样性指数以及Nei氏基因多样度（h）均显示水貂与彩貂品种较〖JP2〗为丰富的遗传多样性。Nei遗传距离、Gst基因分化系数显示水貂与彩貂品种间遗传分化程度不高,遗传变异主要来自种群内。