Proboscivirus | |
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Virus classification | |
Group: | Group I (dsDNA) |
Order: | Herpesvirales |
Family: | Herpesviridae |
Subfamily: | Betaherpesvirinae |
Genus: | Proboscivirus |
Type Species | |
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Proboscivirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Elephants serve as natural hosts. There is currently only one species in this genus: the type species Elephantid herpesvirus 1. EEHV1 is apathogenic for African elephants but causes fatal haemorrhagic disease in Asian elephants. The name "Proboscivirus" comes from the Greek word "προβοσκίς" or "proboscis" meaning "the elephant trunk," for which the virus accordingly uses as its means of contraction and transmission (secretions or openings of the trunk) to enter the elephant's body.
Group: dsDNA
Viruses in Proboscivirus are enveloped, with icosahedral, spherical to pleomorphic, and round geometries, and T=16 symmetry. The diameter is around 150-200 nm. Genomes are linear and non-segmented.
Viral replication is nuclear, and is lysogenic. Entry into the host cell is achieved by attachment of the viral glycoproteins 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. Elephants serve as the natural host.
Proboscivirus is located under the listings of the ICTV Updates as Section §2005.049-050V.04. With the creation of Proboscivirus as a new genus came the creation and categorization of a new species under this genus, by the name of Elephantid Herpesvirus 1 (Acronym: EEHV1 and Scientific Name: Elephant endotheliotropic herpesvirus) under ICTV §2005.051-050V.04.
Proboscivirus retains mammal, bird, and reptile viruses that were incorporated into the original branch of Herpesviridae before its divergence into three subfamilies of: Herpesvirales (of which Proboscivirus is a part of), Alloherpesviridae," and "Malacoherpesviridae. Unassigned species within the genus Proboscivirus include: Caviid Herpesvirus 2 (CavHV2) - Guinea Pig Cytomegalovirus, Suid Herpesvirus 2 (SuHV2) - Pig Cytomegalovirus, Tupaiid Herpesvirus 1 (TuHV1) - Tree Shrew Herpesvirus.
Considering Proboscivirus is a Herpesvirus, it is then unique in the sense that morphologically the virus is atypical to other viruses. According to University of Glasgow Immunology & Virology Professor, A.J. Davison, and his research team, the Proboscivirus morphology is a "linear, double-stranded DNA genome of 125-290 kbp contained within a T=16 icosahedral capsid, which is surrounded by [a] proteinaceous [mixture] and lipid envelope containing membrane-associated proteins". Species under the genus Proboscivirus tend to leave physical symptoms of cyanosis of the tongue, mouth/stomach ulcers, oedema of the head (or trunk for Elephants) on its host - often leading to death afterwards.