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Maedi-visna, Japan (OIE, July 17 2012): 1st occurrence of the disease, sheep

Giuseppe

Giuseppe

Emeritus
[Source: OIE, full page: (LINK). Edited.]


Maedi-visna, Japan


Information received on 17/07/2012 from Dr Toshiro Kawashima, CVO, Animal Health Division, Ministry of Agriculture, Forestry and Fisheries, Tokyo , Japan
  • Summary
    • Report type Immediate notification
    • Start date 03/04/2012
    • Date of first confirmation of the event 03/07/2012
    • Report date 17/07/2012
    • Date submitted to OIE 17/07/2012
    • Reason for notification First occurrence of a listed disease
    • Manifestation of disease Sub-clinical infection
    • Causal agent Maedi-Visna Virus
    • Nature of diagnosis Laboratory (basic), Laboratory (advanced)
    • This event pertains to the whole country
  • New outbreaks
    • Summary of outbreaks
      • Total outbreaks: 1
        • Location(s) IWATE (Morioka-city)
          • Total animals affected: Species ? Susceptible ? Cases ? Deaths ? Destroyed ? Slaughtered
            • Sheep ? 24 ? 1 ? ? ? ? ? ?.
          • Outbreak statistics: Species - Apparent morbidity rate - Apparent mortality rate - Apparent case fatality rate - Proportion susceptible animals lost*
            • Sheep - 4.17% ? ** ? ** ? **
            • * Removed from the susceptible population through death, destruction and/or slaughter
            • ** Not calculated because of missing information
  • Epidemiology
    • Source of the outbreak(s) or origin of infection
      • Unknown or inconclusive
  • Epidemiological comments
    • A veterinarian of a Veterinary University collected blood from the sheep for a research purpose on 3 April 2012 and detected the antibody and the proviral DNA of Maedi-visna virus.
    • The National Institute of Animal Health confirmed the alignment of the DNA extracted from the same sample matched that of Maedi-visna virus on 3 July 2012.
    • According to instructions from Iwate prefectural government, the veterinarian notified it to the government by law on the day.
    • This is the first outbreak of the disease in Japan.
    • On 5 July 2012, Veterinary Authority of MAFF Japan requested all prefectural governments to make the feature of the disease known by sheep farmers and to instruct them to notify it immediately if they find the disease.
    • The susceptible animals including the case animal in the farm are under movement control and their breeding is refrained.
    • The case animal was isolated from the other susceptible animals.
    • Epidemiological surveillance is being carried out to confirm overall picture of the event.
  • Control measures
    • Measures applied
      • Quarantine
      • Movement control inside the country
      • No vaccination
      • No treatment of affected animals
    • Measures to be applied
      • No other measures
  • Diagnostic test results
    • Laboratory name and type National Institute of Animal Health (National laboratory)
      • Tests and results: Species ? Test - Test date ? Result
        • Sheep - gene sequencing - 03/07/2012 ? Positive
  • Future Reporting
    • The event is continuing. Weekly follow-up reports will be submitted.
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Re: Maedi-visna, Japan (OIE, July 17 2012): 1st occurrence of the disease, sheep

Source: Wikipedia: http://en.wikipedia.org/w/index.php?title=Visna_virus&printable=yes



Visna virus

From Wikipedia, the free encyclopedia


Visna virus

Virus classification
Group: Group VI (ssRNA-RT)

Family: Retroviridae

Subfamily: Orthoretrovirinae

Genus: Lentivirus


Visna virus (also known as Visna-Maedi virus, Maedi-Visna virus and ovine lentivirus[1]) from the genus lentivirinae and subfamily Orthoretrovirinae, is a "prototype"[2] retrovirus[3] that causes encephalitis and chronic pneumonitis in sheep.[4] It is known as visna when found in the brain, and maedi when infecting the lungs. Lifelong, persistent infections in sheep occur in the lungs, lymph nodes, spleen, joints, central nervous system, and mammary glands;[2][5] The condition is sometimes known as "ovine progressive pneumonia", particularly in the United States,[1] or "Montana Sheep Disease".[6] White blood cells of the monocyte/macrophage lineage are the main target of Visna virus.[7]


Viral infection

First described in 1954 by Bjorn Sigurdsson in Iceland,[6] Maedi-Visna virus was the first lentivirus to be isolated and characterized, accomplished in 1957 by Sigurdsson.[6][7][8] "Maedi", Icelandic for dyspnoea, and "visna", Icelandic for "wasting"[9] or "shrinking" of the spinal cord, refer to endemic sheep herd conditions that were only found to be related after Sigurdsson's work.[6]

Visna infection may progress to total paralysis leading to death via inanition; however, if helped to obtain water and food, animals may survive for long periods of time, sometimes greater than ten years.[9] Viral replication is almost exclusively associated with macrophages in infected tissues, however replication is restricted in these cells?that is, the majority of cells containing viral RNA do not produce infectious virus.[5]

The disease was introduced to Iceland following an import of Karakul sheep from Germany in 1933.[6] The susceptibility to Maedi-Visna infection varies across sheep breeds, with coarse-wool breeds apparently more susceptible than fine-wool sheep.[6] Attempts at vaccination against Maedi-Visna virus failed to induce immunity, occasionally causing increased viremia and more severe disease.[7] Eradication programs have been established in countries worldwide.[6]


Model system for HIV infection

Though it does not produce severe immunodeficiency, Visna shares many characteristics with human immunodeficiency virus, including the establishment of persistent infection with chronic active lymphoproliferation;[2] however, Visna virus does not infect T-lymphocytes.[7] The relationship of Visna and HIV as lentiviruses was first published in 1985 by Visna researcher Janice E. Clements and colleagues in the HIV field.[10] It has been postulated that the effects of Maedi-Visna infection in sheep are the "equivalent" of central nervous system disease and wasting syndrome found in human AIDS patients.[1][11] Despite limited sequence homology with HIV,[1] the genomic organization of Visna is very similar, allowing Visna infection to be used as an in vivo[12] and in vitro model system for HIV infection.[13][14][15]

Research using Visna was important in the identification and characterization of HIV. Nucleotide sequence analysis demonstrated that the AIDS virus was a retrovirus related to Visna and provided early clues as to the mechanism of HIV infection.[9]

Visna has also been a target for HIV denial hypotheses and conspiracy theories. One such conspiracy theory, promoted by Jakob Segal among others, purports that HIV is a man-made hybrid of Human T-lymphotropic virus maedi-visna.[16]


Control programmes

The maedi-visna control programme of the Swedish Board of Agriculture
Many countries have some sort of national programme to prevent and control a situation where the virus spreads.


References
1.^ a b c d Thormar H (2005). "Maedi-visna virus and its relationship to human immunodeficiency virus". AIDS Rev 7 (4): 233?45. PMID 16425963 (//www.ncbi.nlm.nih.gov/pubmed/16425963) .
2.^ a b c Ryan S, Tiley L, McConnell I, Blacklaws B (November 2000). "Infection of Dendritic Cells by the Maedi-Visna Lentivirus" (http://jvi.asm.org/cgi/pmidlookup?view=long&pmid=11024138) . J. Virol. 74 (21): 10096?103. DOI:10.1128/JVI.74.21.10096-10103.2000 (http://dx.doi.org/10.1128/JVI.74.21.10096-10103.2000) . PMC 102048 (//www.ncbi.nlm.nih.gov/pmc/articles/PMC102048/?tool=pmcentrez) . PMID 11024138 (//www.ncbi.nlm.nih.gov/pubmed/11024138) .
3.^ Wu C, Barbezange C, McConnell I, Blacklaws BA (October 2008). "Mapping and characterization of visna/maedi virus cytotoxic T-lymphocyte epitopes" (http://vir.sgmjournals.org/cgi/pmidlookup?view=long&pmid=18796728) . J. Gen. Virol. 89 (Pt 10): 2586?96. DOI:10.1099/vir.0.2008/002634-0 (http://dx.doi.org/10.1099/vir.0.2008/002634-0) . PMID 18796728 (//www.ncbi.nlm.nih.gov/pubmed/18796728) .
4.^ Benavides J, Garc?a-Pariente C, Fuertes M, et al. (January 2009). "Maedi-visna: the meningoencephalitis in naturally occurring cases" (http://linkinghub.elsevier.com/retrieve/pii/S0021-9975(08)00103-5) . J. Comp. Pathol. 140 (1): 1?11. DOI:10.1016/j.jcpa.2008.07.010 (http://dx.doi.org/10.1016/j.jcpa.2008.07.010) . PMID 18922546 (//www.ncbi.nlm.nih.gov/pubmed/18922546) .
5.^ a b Davis JL, Molineaux S, Clements JE (May 1987). "Visna virus exhibits a complex transcriptional pattern: one aspect of gene expression shared with the acquired immunodeficiency syndrome retrovirus" (http://jvi.asm.org/cgi/pmidlookup?view=long&pmid=3033262) . J. Virol. 61 (5): 1325?31. PMC 254106 (//www.ncbi.nlm.nih.gov/pmc/articles/PMC254106/?tool=pmcentrez) . PMID 3033262 (//www.ncbi.nlm.nih.gov/pubmed/3033262) .
6.^ a b c d e f g Straub OC (January 2004). "Maedi-Visna virus infection in sheep. History and present knowledge" (http://linkinghub.elsevier.com/retrieve/pii/S0147-9571(02)00078-4) . Comp. Immunol. Microbiol. Infect. Dis. 27 (1): 1?5. DOI:10.1016/S0147-9571(02)00078-4 (http://dx.doi.org/10.1016/S0147-9571(02)00078-4) . PMID 14656537 (//www.ncbi.nlm.nih.gov/pubmed/14656537) .
7.^ a b c d Torsteinsdottir S, Andresdottir V, Arnarson H, Petursson G (2007). "Immune response to maedi-visna virus". Front. J Biosci. 12: 1532?43. DOI:10.2741/2166 (http://dx.doi.org/10.2741/2166) . PMID 17127400 (//www.ncbi.nlm.nih.gov/pubmed/17127400) .
8.^ SIGURDSSON B, PALSSON P, GRIMSSON H (July 1957). "Visna, a demyelinating transmissible disease of sheep". J. Neuropathol. Exp. Neurol. 16 (3): 389?403. PMID 13439402 (//www.ncbi.nlm.nih.gov/pubmed/13439402) .
SIGURDSSON B, PALSSON PA (October 1958). "Visna of Sheep. A Slow Demyelinating Infection" (//www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2082258) . Br J Exp Pathol 39 (5): 519?28. PMC 2082258 (//www.ncbi.nlm.nih.gov/pmc/articles/PMC2082258/?tool=pmcentrez) . PMID 13584702 (//www.ncbi.nlm.nih.gov/pubmed/13584702) .
9.^ a b c Sonigo P, Alizon M, Staskus K, et al. (August 1985). "Nucleotide sequence of the visna lentivirus: relationship to the AIDS virus" (http://linkinghub.elsevier.com/retrieve/pii/S0092-8674(85)80132-X) . Cell 42 (1): 369?82. DOI:10.1016/S0092-8674(85)80132-X (http://dx.doi.org/10.1016/S0092-8674(85)80132-X) . PMID 2410140 (//www.ncbi.nlm.nih.gov/pubmed/2410140) .
10.^ Gonda MA, Wong-Staal F, Gallo RC, Clements JE, Narayan O, Gilden RV. Sequence homology and morphologic similarity of HTLV-III and visna virus, a pathogenic lentivirus. Science. 1985 Jan 11;227(4683):173-7.
11.^ Forsman A, Weiss RA (December 2008). "Why is HIV a pathogen?" (http://linkinghub.elsevier.com/retrieve/pii/S0966-842X(08)00227-8) . Trends Microbiol. 16 (12): 555?60. DOI:10.1016/j.tim.2008.09.004 (http://dx.doi.org/10.1016/j.tim.2008.09.004) . PMID 18977141 (//www.ncbi.nlm.nih.gov/pubmed/18977141) .
12.^ Adv Pharmacol. 2000;49:315-85. "HIV-1-associated central nervous system dysfunction." Krebs FC, Ross H, McAllister J, Wigdahl B.
13.^ Frank KB, McKernan PA, Smith RA, Smee DF (September 1987). "Visna virus as an in vitro model for human immunodeficiency virus and inhibition by ribavirin, phosphonoformate, and 2',3'-dideoxynucleosides" (http://aac.asm.org/cgi/pmidlookup?view=long&pmid=2445282) . Antimicrob. Agents Chemother. 31 (9): 1369?74. PMC 174944 (//www.ncbi.nlm.nih.gov/pmc/articles/PMC174944/?tool=pmcentrez) . PMID 2445282 (//www.ncbi.nlm.nih.gov/pubmed/2445282) .
14.^ Salvatori D, Vincenzetti S, Maury G, Gosselin G, Gaubert G, Vita A (April 2001). "Maedi-visna virus, a model for in vitro testing of potential anti-HIV drugs" (http://linkinghub.elsevier.com/retrieve/pii/S0147-9571(00)00021-7) . Comp. Immunol. Microbiol. Infect. Dis. 24 (2): 113?22. DOI:10.1016/S0147-9571(00)00021-7 (http://dx.doi.org/10.1016/S0147-9571(00)00021-7) . PMID 11247044 (//www.ncbi.nlm.nih.gov/pubmed/11247044) .
15.^ Salvatori D, Volpini R, Vincenzetti S, et al. (September 2002). "Adenine and deazaadenine nucleoside and deoxynucleoside analogues: inhibition of viral replication of sheep MVV (in vitro model for HIV) and bovine BHV-1" (http://linkinghub.elsevier.com/retrieve/pii/S0968089602001311) . Bioorg. Med. Chem. 10 (9): 2973?80. DOI:10.1016/S0968-0896(02)00131-1 (http://dx.doi.org/10.1016/S0968-0896(02)00131-1) . PMID 12110319 (//www.ncbi.nlm.nih.gov/pubmed/12110319) .
16.^ "Of Myths and Mischief" (http://discovermagazine.com/1994/dec/ofmythsandmischi458) , Discover, 1 December 1994

External links
■Visna/maedi virus (http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/) ICTVdB - The Universal Virus Database, version 4
■Ovine Progressive Pneumonia in Sheep (http://www.extension.umn.edu/distribution/livestocksystems/DI5750.html) , University of Minnesota Extension


Retrieved from "http://en.wikipedia.org/w/index.php?title=Visna_virus&oldid=500236136"

Categories: Sheep and goat diseases
Animal virology
Lentiviruses

■ This page was last modified on 1 July 2012 at 21:48.
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