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
  • 20 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • visna/maedi virus
  • Taxonomic Tree
  • Domain: Virus
  •   Group: "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
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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
  •     Group: "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.

Last updated: 10 Jan 2020
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Africa

AlgeriaAbsent, No presence record(s)OIE Handistatus (2005)
BotswanaAbsent, No presence record(s)OIE Handistatus (2005)
BurundiAbsent, No presence record(s)OIE Handistatus (2005)
Cabo VerdeAbsent, No presence record(s)OIE Handistatus (2005)
CameroonAbsent, No presence record(s)OIE Handistatus (2005)
Central African RepublicAbsent, No presence record(s)OIE Handistatus (2005)
Congo, Democratic Republic of theAbsent, No presence record(s)OIE Handistatus (2005)
Côte d'IvoireAbsent, No presence record(s)OIE Handistatus (2005)
DjiboutiAbsent, No presence record(s)OIE Handistatus (2005)
EgyptAbsent, No presence record(s)OIE Handistatus (2005)
EritreaAbsent, No presence record(s)OIE Handistatus (2005)
EswatiniAbsent, No presence record(s)OIE Handistatus (2005)
GhanaAbsent, No presence record(s)OIE Handistatus (2005)
GuineaAbsent, No presence record(s)OIE Handistatus (2005)
LibyaAbsent, No presence record(s)OIE Handistatus (2005)
MadagascarAbsent, No presence record(s)OIE Handistatus (2005)
MauritiusAbsent, No presence record(s)OIE Handistatus (2005)
MoroccoAbsent, No presence record(s)OIE Handistatus (2005)
NigeriaAbsent, No presence record(s)OIE Handistatus (2005)
SeychellesAbsent, No presence record(s)OIE Handistatus (2005)
South AfricaPresentOIE Handistatus (2005)
SudanAbsent, No presence record(s)OIE Handistatus (2005)
TanzaniaAbsent, No presence record(s)OIE Handistatus (2005)
TogoAbsent, No presence record(s)OIE Handistatus (2005)
TunisiaAbsent, No presence record(s)OIE Handistatus (2005)
UgandaAbsent, No presence record(s)OIE Handistatus (2005)
ZambiaAbsent, No presence record(s)OIE Handistatus (2005)
ZimbabweAbsent, No presence record(s)OIE Handistatus (2005)

Asia

BahrainAbsent, No presence record(s)OIE Handistatus (2005)
BhutanAbsent, No presence record(s)OIE Handistatus (2005)
BruneiAbsent, No presence record(s)OIE Handistatus (2005)
ChinaPresentCABI Data Mining (2001)
GeorgiaAbsent, No presence record(s)OIE Handistatus (2005)
Hong KongAbsent, No presence record(s)OIE Handistatus (2005)
IndiaAbsent, No presence record(s)OIE Handistatus (2005)
IndonesiaAbsent, No presence record(s)OIE Handistatus (2005)
IranAbsent, No presence record(s)OIE Handistatus (2005)
IraqPresent, Serological evidence and/or isolation of the agentOIE Handistatus (2005)
JapanAbsent, No presence record(s)OIE Handistatus (2005)
JordanAbsent, No presence record(s)OIE Handistatus (2005)
KazakhstanAbsent, No presence record(s)OIE Handistatus (2005)
KuwaitAbsent, No presence record(s)OIE Handistatus (2005)
LebanonAbsent, No presence record(s)OIE Handistatus (2005)
Malaysia
-Peninsular MalaysiaAbsent, No presence record(s)OIE Handistatus (2005)
-SabahAbsent, No presence record(s)OIE Handistatus (2005)
-SarawakAbsent, No presence record(s)OIE Handistatus (2005)
MongoliaAbsent, No presence record(s)OIE Handistatus (2005)
NepalAbsent, No presence record(s)OIE Handistatus (2005)
North KoreaAbsent, No presence record(s)OIE Handistatus (2005)
OmanAbsent, No presence record(s)OIE Handistatus (2005)
QatarAbsent, No presence record(s)OIE Handistatus (2005)
SingaporeAbsent, No presence record(s)OIE Handistatus (2005)
South KoreaAbsent, No presence record(s)OIE Handistatus (2005)
Sri LankaAbsent, No presence record(s)OIE Handistatus (2005)
SyriaAbsent, No presence record(s)OIE Handistatus (2005)
TaiwanAbsent, No presence record(s)OIE Handistatus (2005)
ThailandAbsent, No presence record(s)OIE Handistatus (2005)
TurkmenistanAbsent, No presence record(s)OIE Handistatus (2005)
UzbekistanAbsent, No presence record(s)OIE Handistatus (2005)
VietnamAbsent, No presence record(s)OIE Handistatus (2005)

Europe

AndorraPresent, Serological evidence and/or isolation of the agentOIE Handistatus (2005)
BelarusAbsent, No presence record(s)OIE Handistatus (2005)
BelgiumPresentOIE Handistatus (2005)
Bosnia and HerzegovinaAbsent, No presence record(s)OIE Handistatus (2005)
CroatiaAbsent, No presence record(s)OIE Handistatus (2005)
CyprusPresent, Serological evidence and/or isolation of the agentOIE Handistatus (2005)
DenmarkPresentOIE Handistatus (2005)
EstoniaAbsent, No presence record(s)OIE Handistatus (2005)
FrancePresentOIE Handistatus (2005)
GermanyPresentOIE Handistatus (2005)
HungaryPresentOIE Handistatus (2005)
Isle of ManAbsent, No presence record(s)OIE Handistatus (2005)
JerseyAbsent, No presence record(s)OIE Handistatus (2005)
LatviaPresent, Serological evidence and/or isolation of the agentOIE Handistatus (2005)
LiechtensteinAbsent, No presence record(s)OIE Handistatus (2005)
LithuaniaAbsent, No presence record(s)OIE Handistatus (2005)
LuxembourgPresentOIE Handistatus (2005)
MaltaAbsent, No presence record(s)OIE Handistatus (2005)
MoldovaAbsent, No presence record(s)OIE Handistatus (2005)
NetherlandsPresentOIE Handistatus (2005)
North MacedoniaAbsent, No presence record(s)OIE Handistatus (2005)
NorwayPresentOIE Handistatus (2005)
PortugalPresentOIE Handistatus (2005)
RussiaAbsent, No presence record(s)OIE Handistatus (2005)
SlovakiaPresent, Serological evidence and/or isolation of the agentOIE Handistatus (2005)
SloveniaAbsent, No presence record(s)OIE Handistatus (2005)
SwedenPresentOIE Handistatus (2005)
SwitzerlandPresentOIE Handistatus (2005)
UkraineAbsent, No presence record(s)OIE Handistatus (2005)
United KingdomPresentOIE Handistatus (2005)
-Northern IrelandAbsent, No presence record(s)OIE Handistatus (2005)

North America

BarbadosAbsent, No presence record(s)OIE Handistatus (2005)
BelizeAbsent, No presence record(s)OIE Handistatus (2005)
BermudaAbsent, No presence record(s)OIE Handistatus (2005)
British Virgin IslandsAbsent, No presence record(s)OIE Handistatus (2005)
CanadaPresent, Serological evidence and/or isolation of the agentOIE Handistatus (2005)
Cayman IslandsAbsent, No presence record(s)OIE Handistatus (2005)
Costa RicaAbsent, No presence record(s)OIE Handistatus (2005)
CubaAbsent, No presence record(s)OIE Handistatus (2005)
CuraçaoAbsent, No presence record(s)OIE Handistatus (2005)
DominicaAbsent, No presence record(s)OIE Handistatus (2005)
Dominican RepublicAbsent, No presence record(s)OIE Handistatus (2005)
El SalvadorAbsent, No presence record(s)OIE Handistatus (2005)
GuadeloupeAbsent, No presence record(s)OIE Handistatus (2005)
GuatemalaAbsent, No presence record(s)OIE Handistatus (2005)
HaitiAbsent, No presence record(s)OIE Handistatus (2005)
HondurasAbsent, No presence record(s)OIE Handistatus (2005)
JamaicaAbsent, No presence record(s)OIE Handistatus (2005)
MartiniqueAbsent, No presence record(s)OIE Handistatus (2005)
MexicoAbsent, No presence record(s)OIE Handistatus (2005)
NicaraguaAbsent, No presence record(s)OIE Handistatus (2005)
PanamaAbsent, No presence record(s)OIE Handistatus (2005)
Saint Kitts and NevisAbsent, No presence record(s)OIE Handistatus (2005)
Saint Vincent and the GrenadinesAbsent, No presence record(s)OIE Handistatus (2005)
Trinidad and TobagoAbsent, No presence record(s)OIE Handistatus (2005)
United StatesPresentOIE Handistatus (2005)

Oceania

AustraliaAbsent, No presence record(s)OIE Handistatus (2005)
French PolynesiaAbsent, No presence record(s)OIE Handistatus (2005)
New CaledoniaAbsent, No presence record(s)OIE Handistatus (2005)
New ZealandAbsent, No presence record(s)OIE Handistatus (2005)
SamoaAbsent, No presence record(s)OIE Handistatus (2005)
VanuatuAbsent, No presence record(s)OIE Handistatus (2005)

South America

ArgentinaPresent, Serological evidence and/or isolation of the agentOIE Handistatus (2005)
BoliviaAbsent, No presence record(s)OIE Handistatus (2005)
BrazilAbsent, No presence record(s)OIE Handistatus (2005)
ColombiaAbsent, No presence record(s)OIE Handistatus (2005)
EcuadorAbsent, No presence record(s)OIE Handistatus (2005)
Falkland IslandsAbsent, No presence record(s)OIE Handistatus (2005)
French GuianaAbsent, No presence record(s)OIE Handistatus (2005)
GuyanaAbsent, No presence record(s)OIE Handistatus (2005)
ParaguayAbsent, No presence record(s)OIE Handistatus (2005)
PeruAbsent, No presence record(s)OIE Handistatus (2005)
UruguayAbsent, No presence record(s)OIE Handistatus (2005)
VenezuelaAbsent, No presence record(s)OIE 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 References

CABI Data Mining, 2001. CAB Abstracts Data Mining.,

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

Distribution Maps

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