Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

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visna/maedi virus

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Datasheet

visna/maedi virus

Summary

  • Last modified
  • 14 July 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • visna/maedi virus
  • Taxonomic Tree
  • Domain: Virus
  •   Unknown: "DNA and RNA reverse transcribing viruses"
  •     Family: Retroviridae
  •       Genus: Lentivirus
  •         Species: visna/maedi virus
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    Compendia
    CAB International
    Wallingford
    Oxfordshire
    OX10 8DE
    UK
    compend@cabi.org
  • Distribution map More information

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Identity

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Preferred Scientific Name

  • visna/maedi virus (ICTV)

Other Scientific Names

  • maedi virus
  • maedi-visna virus (Pepin et al., 1998)
  • visna virus
  • visna/maedi virus (strain 1514)
  • visna-maedi virus

International Common Names

  • English: ovine lentivirus; ovine progressive pneumonia virus

English acronym

  • MVV
  • VISNA
  • VMV

Taxonomic Tree

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  • Domain: Virus
  •     Unknown: "DNA and RNA reverse transcribing viruses"
  •         Family: Retroviridae
  •             Genus: Lentivirus
  •                 Species: visna/maedi virus

Diseases Table

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Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

AzerbaijanNo information availableOIE Handistatus, 2005
BahrainDisease never reportedOIE Handistatus, 2005
BhutanDisease never reportedOIE Handistatus, 2005
Brunei DarussalamDisease not reportedOIE Handistatus, 2005
ChinaPresentCAB ABSTRACTS Data Mining 2001
-Hong KongDisease never reportedOIE Handistatus, 2005
Georgia (Republic of)Disease never reportedOIE Handistatus, 2005
IndiaDisease not reportedOIE Handistatus, 2005
IndonesiaDisease never reportedOIE Handistatus, 2005
IranDisease never reportedOIE Handistatus, 2005
IraqSerological evidence and/or isolation of the agentOIE Handistatus, 2005
IsraelNo information availableOIE Handistatus, 2005
JapanDisease never reportedOIE Handistatus, 2005
JordanDisease never reportedOIE Handistatus, 2005
KazakhstanDisease never reportedOIE Handistatus, 2005
Korea, DPRDisease not reportedOIE Handistatus, 2005
Korea, Republic ofDisease never reportedOIE Handistatus, 2005
KuwaitDisease not reportedOIE Handistatus, 2005
LebanonDisease not reportedOIE Handistatus, 2005
Malaysia
-Peninsular MalaysiaDisease never reportedOIE Handistatus, 2005
-SabahDisease never reportedOIE Handistatus, 2005
-SarawakDisease never reportedOIE Handistatus, 2005
MongoliaDisease never reportedOIE Handistatus, 2005
MyanmarNo information availableOIE Handistatus, 2005
NepalDisease never reportedOIE Handistatus, 2005
OmanDisease not reportedOIE Handistatus, 2005
PhilippinesNo information availableOIE Handistatus, 2005
QatarDisease not reportedOIE Handistatus, 2005
SingaporeDisease never reportedOIE Handistatus, 2005
Sri LankaDisease never reportedOIE Handistatus, 2005
SyriaDisease not reportedOIE Handistatus, 2005
TaiwanDisease never reportedOIE Handistatus, 2005
TajikistanNo information availableOIE Handistatus, 2005
ThailandDisease never reportedOIE Handistatus, 2005
TurkeyNo information availableOIE Handistatus, 2005
TurkmenistanDisease not reportedOIE Handistatus, 2005
United Arab EmiratesNo information availableOIE Handistatus, 2005
UzbekistanDisease never reportedOIE Handistatus, 2005
VietnamDisease never reportedOIE Handistatus, 2005
YemenNo information availableOIE Handistatus, 2005

Africa

AlgeriaDisease not reportedOIE Handistatus, 2005
AngolaNo information availableOIE Handistatus, 2005
BeninNo information availableOIE Handistatus, 2005
BotswanaDisease not reportedOIE Handistatus, 2005
Burkina FasoNo information availableOIE Handistatus, 2005
BurundiDisease never reportedOIE Handistatus, 2005
CameroonDisease never reportedOIE Handistatus, 2005
Cape VerdeDisease never reportedOIE Handistatus, 2005
Central African RepublicDisease not reportedOIE Handistatus, 2005
ChadNo information availableOIE Handistatus, 2005
Congo Democratic RepublicDisease not reportedOIE Handistatus, 2005
Côte d'IvoireDisease not reportedOIE Handistatus, 2005
DjiboutiDisease not reportedOIE Handistatus, 2005
EgyptDisease never reportedOIE Handistatus, 2005
EritreaDisease not reportedOIE Handistatus, 2005
GhanaDisease not reportedOIE Handistatus, 2005
GuineaDisease never reportedOIE Handistatus, 2005
Guinea-BissauNo information availableOIE Handistatus, 2005
KenyaNo information availableOIE Handistatus, 2005
LibyaDisease never reportedOIE Handistatus, 2005
MadagascarDisease never reportedOIE Handistatus, 2005
MalawiNo information availableOIE Handistatus, 2005
MaliNo information availableOIE Handistatus, 2005
MauritiusDisease not reportedOIE Handistatus, 2005
MoroccoDisease never reportedOIE Handistatus, 2005
MozambiqueNo information availableOIE Handistatus, 2005
NamibiaLast reported1988OIE Handistatus, 2005
NigeriaDisease never reportedOIE Handistatus, 2005
RéunionNo information availableOIE Handistatus, 2005
RwandaNo information availableOIE Handistatus, 2005
Sao Tome and PrincipeLast reported2003OIE Handistatus, 2005
SenegalNo information availableOIE Handistatus, 2005
SeychellesDisease not reportedOIE Handistatus, 2005
SomaliaNo information availableOIE Handistatus, 2005
South AfricaReported present or known to be presentOIE Handistatus, 2005
SudanDisease never reportedOIE Handistatus, 2005
SwazilandDisease never reportedOIE Handistatus, 2005
TanzaniaDisease not reportedOIE Handistatus, 2005
TogoDisease never reportedOIE Handistatus, 2005
TunisiaDisease not reportedOIE Handistatus, 2005
UgandaDisease not reportedOIE Handistatus, 2005
ZambiaDisease never reportedOIE Handistatus, 2005
ZimbabweDisease never reportedOIE Handistatus, 2005

North America

BermudaDisease not reportedOIE Handistatus, 2005
CanadaSerological evidence and/or isolation of the agentOIE Handistatus, 2005
MexicoDisease never reportedOIE Handistatus, 2005
USAReported present or known to be presentOIE Handistatus, 2005

Central America and Caribbean

BarbadosDisease never reportedOIE Handistatus, 2005
BelizeDisease never reportedOIE Handistatus, 2005
British Virgin IslandsDisease never reportedOIE Handistatus, 2005
Cayman IslandsDisease not reportedOIE Handistatus, 2005
Costa RicaDisease never reportedOIE Handistatus, 2005
CubaDisease never reportedOIE Handistatus, 2005
CuraçaoDisease not reportedOIE Handistatus, 2005
DominicaDisease not reportedOIE Handistatus, 2005
Dominican RepublicDisease never reportedOIE Handistatus, 2005
El SalvadorDisease never reportedOIE Handistatus, 2005
GuadeloupeDisease never reportedOIE Handistatus, 2005
GuatemalaDisease never reportedOIE Handistatus, 2005
HaitiDisease never reportedOIE Handistatus, 2005
HondurasDisease never reportedOIE Handistatus, 2005
JamaicaDisease never reportedOIE Handistatus, 2005
MartiniqueDisease not reportedOIE Handistatus, 2005
NicaraguaDisease never reportedOIE Handistatus, 2005
PanamaDisease never reportedOIE Handistatus, 2005
Saint Kitts and NevisDisease never reportedOIE Handistatus, 2005
Saint Vincent and the GrenadinesDisease not reportedOIE Handistatus, 2005
Trinidad and TobagoDisease never reportedOIE Handistatus, 2005

South America

ArgentinaSerological evidence and/or isolation of the agentOIE Handistatus, 2005
BoliviaDisease never reportedOIE Handistatus, 2005
BrazilDisease never reportedOIE Handistatus, 2005
ChileOIE Handistatus, 2005
ColombiaDisease never reportedOIE Handistatus, 2005
EcuadorDisease never reportedOIE Handistatus, 2005
Falkland IslandsDisease never reportedOIE Handistatus, 2005
French GuianaDisease not reportedOIE Handistatus, 2005
GuyanaDisease not reportedOIE Handistatus, 2005
ParaguayDisease never reportedOIE Handistatus, 2005
PeruDisease not reportedOIE Handistatus, 2005
UruguayDisease never reportedOIE Handistatus, 2005
VenezuelaDisease never reportedOIE Handistatus, 2005

Europe

AndorraSerological evidence and/or isolation of the agentOIE Handistatus, 2005
AustriaLast reported1996OIE Handistatus, 2005
BelarusDisease never reportedOIE Handistatus, 2005
BelgiumReported present or known to be presentOIE Handistatus, 2005
Bosnia-HercegovinaDisease not reportedOIE Handistatus, 2005
BulgariaLast reported2001OIE Handistatus, 2005
CroatiaDisease never reportedOIE Handistatus, 2005
CyprusSerological evidence and/or isolation of the agentOIE Handistatus, 2005
Czech RepublicLast reported2003OIE Handistatus, 2005
DenmarkReported present or known to be presentOIE Handistatus, 2005
EstoniaDisease never reportedOIE Handistatus, 2005
FinlandLast reported2002OIE Handistatus, 2005
FranceReported present or known to be presentOIE Handistatus, 2005
GermanyReported present or known to be presentOIE Handistatus, 2005
GreeceOIE Handistatus, 2005
HungaryReported present or known to be presentOIE Handistatus, 2005
IcelandLast reported1965OIE Handistatus, 2005
IrelandLast reported1986OIE Handistatus, 2005
Isle of Man (UK)Disease not reportedOIE Handistatus, 2005
ItalyNo information availableOIE Handistatus, 2005
JerseyDisease never reportedOIE Handistatus, 2005
LatviaSerological evidence and/or isolation of the agentOIE Handistatus, 2005
LiechtensteinDisease not reportedOIE Handistatus, 2005
LithuaniaDisease never reportedOIE Handistatus, 2005
LuxembourgReported present or known to be presentOIE Handistatus, 2005
MacedoniaDisease never reportedOIE Handistatus, 2005
MaltaDisease never reportedOIE Handistatus, 2005
MoldovaDisease never reportedOIE Handistatus, 2005
NetherlandsReported present or known to be presentOIE Handistatus, 2005
NorwayReported present or known to be presentOIE Handistatus, 2005
PolandLast reported1997OIE Handistatus, 2005
PortugalReported present or known to be presentOIE Handistatus, 2005
RomaniaOIE Handistatus, 2005
Russian FederationDisease never reportedOIE Handistatus, 2005
SlovakiaSerological evidence and/or isolation of the agentOIE Handistatus, 2005
SloveniaDisease never reportedOIE Handistatus, 2005
SpainOIE Handistatus, 2005
SwedenReported present or known to be presentOIE Handistatus, 2005
SwitzerlandReported present or known to be presentOIE Handistatus, 2005
UKReported present or known to be presentOIE Handistatus, 2005
-Northern IrelandDisease never reportedOIE Handistatus, 2005
UkraineDisease never reportedOIE Handistatus, 2005
Yugoslavia (former)No information availableOIE Handistatus, 2005
Yugoslavia (Serbia and Montenegro)No information availableOIE Handistatus, 2005

Oceania

AustraliaDisease never reportedOIE Handistatus, 2005
French PolynesiaDisease not reportedOIE Handistatus, 2005
New CaledoniaDisease never reportedOIE Handistatus, 2005
New ZealandDisease never reportedOIE Handistatus, 2005
SamoaDisease never reportedOIE Handistatus, 2005
VanuatuDisease never reportedOIE Handistatus, 2005
Wallis and Futuna IslandsNo information availableOIE Handistatus, 2005

Pathogen Characteristics

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Visna/maedi virus is the prototype Lentivirus belonging to subfamily Lentivirinae of the family Retroviridae, together with human immunodeficiency viruses (HIV-1 and HIV-2 viruses), caprine arthritis-encephalitis virus (CAEV), and the simian, bovine, feline immunodeficiency viruses (SIV, BIV and FIV respectively), and equine infectious anaemia virus (EIAV). Importantly, visna/maedi virus is a species-specific but not oncogenic virus. Depending on the cell type, visna/maedi virus infection may lead to a cytopathic effect, or remain unnoticed. This has important consequences for pathology and viral persistence.

Visna/maedi virus is a dimer of positive sense RNA of about 9.2 kb in size (Carey and Dalziel, 1993). Virus replication occurs by reverse transcription of the genome using the virus-encoded RNA-dependent DNA polymerase, and occurs via a DNA intermediate. Part of the proviral DNA is incorporated into the host genome. The genome of lentiviruses contains the structural genes (gag-group specific antigen and env-envelope), and enzymatic gene (pol-polymerase), typical for retroviruses. Analogous to other retroviruses, visna/maedi virus proviral DNA is flanked by long terminal repeats (LTR) that provide the cis signals required for transcription, integration and polyadenylation of viral RNA. LTR of visna/maedi virus may be involved in cell tropism (Agnarsdottir et al., 2000).

The gag-gene encodes for three proteins: the capsid or core protein (p25), the nucleocapsid (p14) and the matrix (MA) protein (p17), which ensures the link between the capsid and the envelope. The hydrophobic capsid protein is the most abundant constituent protein of visna\maedi virus. This capsid protein elicits a strong induction of antibodies upon infection, an effect that is used in diagnostic tests.

The env-gene encodes the glycoprotein of the virus. The precursor protein gp160 is cleaved into two subunits: the surface glycoprotein (SU: gp135), and the transmembrane glycoprotein (TM: gp44). The envelope glycoproteins of visna\maedi virus have important biological functions. They contain epitopes responsible for the induction of neutralising antibodies, and for interaction with cellular receptors during the replication cycle.

The pol-gene encodes the RNA-dependent DNA-polymerase, which is a heterodimer that permits transcription of the viral RNA into DNA.

Other visna/maedi virus-encoded enzymes are dUTPase, integrase and protease (Pepin et al., 1998).

Auxiliary genes that are not essential for virus replication further mediate the level of viral expression in lentiviruses. Visna/maedi virus also contains several short, multiply spliced ORFs that encode proteins which are thought to have regulatory function (Carey and Dalziel, 1993). Visna/maedi virus has three auxiliary genes: tat, vif-viral infectivity factor (previously called Q gene) and rev-regulator of virion protein expression.

The tat-gene encodes a 10 kDa protein, and mediates the accumulation of viral RNA. The vif-gene encodes a 29 kDa protein, and induces a weak immune response and is thought to play a role in the late stages of the viral life cycle, specifically during the morphogenesis of the viral nucleoprotein core. The rev-gene encodes a 19 kDa protein and plays a role in the early phase of visna\maedi virus replication, by transporting unspliced mRNA from the nucleus to the cytoplasm. The rev gene seems to be essential for visna/maedi virus replication as the rev-mutagenised virus appears uninfectious (Pepin et al., 1998).

Lentiviruses can be roughly separated into two groups based on their cell tropism. Visna/maedi virus, CAEV and EIAV replicate strictly in macrophages and monocytes, whereas the primate lentiviruses HIV and SIV also replicate in CD4+ lymphocytes (Narayan et al., 1997). Importantly, lentiviruses are capable to replicate in non-dividing terminally differentiated cells. This implies that cellular DNA replication is not required for integration of the viral DNA into the cellular genome. It is currently unknown whether the auxiliary genes of the lentiviruses, as opposed to the oncogenic retroviruses, play a role in altering the non-dividing cells to provide the necessary enzymes and metabolites for viral DNA replication and integration (Clements et al., 1994; Narayan et al., 1997).

The Lentivirusgag, pol en env genes encode proteins that comprise the infectious viral particle. Lentiviruses bud from the cell membrane in a fashion similar to the oncogenic retroviruses. However, in some cell types such as macrophages and endothelial cells, lentiviruses bud internally into intracellular vacuoles, thereby providing a reservoir of infectious virus particles that are not exposed to the cell surface and cannot be recognised by the immune system (Narayan et al., 1997).

After infection, the virus can establish itself into the genomic material of the host as proviral DNA, and reside in a quiescent proviral state for several months. At a given moment the virus is activated by cellular and viral factors and the disease starts to develop.

Genetically, lentiviruses are quite heterogeneous. This may contribute to persistence in the host by permitting immune evasion. The antigenic diversity also presents a huge obstacle in Lentivirus vaccine development. Antigenically distinct viruses have been isolated from sheep persistently infected with visna/maedi virus. These variants arose from mutations in the env-gene (Pepin et al., 1998).

Various strains of visna/maedi virus differ in their pathogenicity in vitro and in vivo. This may be accompanied by differences in phenotypic characteristics such as absence of cytopathic effect in alveolar macrophages.

Disease(s) associated with this pathogen is/are on the list of diseases notifiable to the World Organisation for Animal Health (OIE). The distribution section contains data from OIE's Handistatus database on disease occurrence. Please see the AHPC library for further information from OIE, including the International Animal Health Code and the Manual of Standards for Diagnostic Tests and Vaccines. Also see the website: www.oie.int.

Host Animals

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Animal nameContextLife stageSystem
Capra hircus (goats)Domesticated host
Ovis aries (sheep)Domesticated host
Ovis aries musimon (European mouflon)Wild host

References

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Agnarsdottir G; Thorsteinsdottir H; Oskarsson T; Matthiasdottir S; St Haflidadottir B; Andresson OS; Andresdottir V, 2000. The long terminal repeat is a determinant of cell tropism of maedi- visna virus. J. Gen. Virol., 81(8):1901-1905.

Carey N; Dalziel RG, 1993. The biology of maedi-visna virus- an overview. British Veterinary Journal, 149(5):437-454; 100 ref.

Clements JE; Zink MC; Narayan O; Gabuzda DH, 1994. Lentivirus infection of macrophages. Immunol. Ser., 60:589-600.

Narayan O; Joag SV; Chebloune Y; Zink MC; Clements JE, 1997. Visna-Maedi: the prototype lentiviral disease. In: Nathanson N, Ahmed R, Gonzalez-Scarano F, Griffin DE, Holmes KV, Murphy FA, Robinson HL, eds. Viral Pathogenesis. Philadelphia, USA: Lippincott-Raven, 657-668. ISBN 0-7817-0297-6.

OIE Handistatus, 2002. World Animal Health Publication and Handistatus II (dataset for 2001). Paris, France: Office International des Epizooties.

OIE Handistatus, 2003. World Animal Health Publication and Handistatus II (dataset for 2002). Paris, France: Office International des Epizooties.

OIE Handistatus, 2004. World Animal Health Publication and Handistatus II (data set for 2003). Paris, France: Office International des Epizooties.

OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (data set for 2004). Paris, France: Office International des Epizooties.

Pépin M; Vitu C; Russo P; Mornex JF; Peterhans E, 1998. Maedi-visna virus infection in sheep: a review. Veterinary Research, 29(3/4):341-367; many ref.

Distribution Maps

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