''Mardivirus'' is a genus of

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsk ...

es in the order ''

Herpesvirales The ''Herpesvirales'' is an order of dsDNA viruses (Baltimore group I) with animal hosts, characterised by a common morphology consisting of an icosahedral capsid enclosed in a glycoprotein-containing lipid envelope. Common infections in humans ...

'', in the family ''

Herpesviridae ''Herpesviridae'' is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word ''ἕρπει� ...

'', in the subfamily ''

Alphaherpesvirinae ''Alphaherpesvirinae'' is a subfamily of viruses in the family ''Herpesviridae'', primarily distinguished by reproducing more quickly than other subfamilies in the ''Herpesviridae''. In animal virology the most important herpesviruses belong to ...

''. Chickens, turkeys, and quail serve as natural hosts. There are six species in this genus. Diseases associated with this genus include:

Marek's disease Marek's disease is a highly contagious viral neoplastic disease in chickens. It is named after József Marek, a Hungarian veterinarian who described it in 1907. Marek's disease is caused by an alphaherpesvirus known as "Marek's disease virus" ...

, which causes asymmetric paralysis of one or more limbs, neurological symptoms, and development of multiple lymphomas that manifest as solid tumors. ''Gallid herpesvirus 2'' (also known as Marek's disease virus) is the only one of these viruses known to be pathogenic and due to the antigenic similarity between the three viruses the other two have been used to vaccinate against Marek's disease. These viruses have double stranded DNA genomes with no RNA intermediate.

Species

The genus consists of the following six species: * '' Anatid alphaherpesvirus 1'' * '' Columbid alphaherpesvirus 1'' * '' Gallid alphaherpesvirus 2'' * '' Gallid alphaherpesvirus 3'' * '' Meleagrid alphaherpesvirus 1'' * '' Spheniscid alphaherpesvirus 1''

Structure

Viruses in ''Mardivirus'' are enveloped, with icosahedral, spherical to pleomorphic, and round geometries, and T=16 symmetry. The diameter is around 120-200 nm. Genomes are linear and non-segmented, around 175kb in length.

Life cycle

Viral replication is nuclear, and is lysogenic. Entry into the host cell is achieved by attachment of the viral gB, gC, gD and gH proteins to host receptors, which mediates endocytosis. Replication follows the dsDNA bidirectional replication model. DNA-templated transcription, with some alternative splicing mechanism is the method of transcription. The virus exits the host cell by nuclear egress, and budding. Chickens, turkeys, and quail serve as the natural host.

Replication

The stages of replication are similar to other viruses in ''

'', but there are a few differences. After the virus has entered the cell the nucleocapsids make their way to a nuclear pore where the virus genome is released and translocates into the nucleus. The virus genome replicates and is packaged up within the nucleus, this new nucleocapsid then buds from the inner nuclear membrane and so gains its primary envelope. The nucleocapsid is now in the perinuclear space in the endoplasmic reticulum, from here the nucleocapsid buds from the outer nuclear membrane and by an unknown mechanism loses its primary envelope leaving the nucleocapsid naked in the cytoplasm. The nucleocapsids finally gain their secondary envelopes by budding into cytoplasmic vesicles within the cell.

References

External links

Viralzone: ''Mardivirus''

ICTV

Virus Pathogen Database and Analysis Resource (ViPR): ''Herpesviridae''
{{Taxonbar, from=Q1894465 Alphaherpesvirinae Poultry diseases Virus genera