''Orthohepevirus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 Ivanovsky's 1 ...

es assigned to the family ''

Hepeviridae ''Hepeviridae'' is a family of viruses. Human, pig, wild boar, sheep, cow, camel, monkey, some rodents, bats and chickens serve as natural hosts. There are two genera in the family. Diseases associated with this family include: hepatitis; high m ...

''. ''Orthohepevirus'' is a fairly isolated viral genus in which the virions are characterized by round, non-enveloped and isometric

capsid A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may ...

s with a diameter of 27–34 nm. The hepatitis E virus belongs this genus as the species ''Orthohepevirus A''

Genome

Orthohepeviruses have RNA genomes of 7176

nucleotides Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules w ...

in length and infect vertebrates. Additionally, the genome is monopartite, linear, and single-stranded. The genome is 5' capped with a poly A tail at the 3' end. The genome possesses three main

open reading frame In molecular biology, open reading frames (ORFs) are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible readin ...

s. The first encodes non-structural proteins, the second encodes the capsid proteins, and the third encodes a small, multifunctional protein.

Taxonomy

Viruses from this genus have been isolated from a variety of mammals (including rodents, mustelids and bats) as well as birds. At least three variants of avian hepatitis E virus have been isolated from birds. A Hepatitis E-like virus has been isolated from a Swedish moose. This virus is quite distinct from the other known Hepatitis E viruses. In total, the genus has four recognized species: '' Orthohepevirus A'', ''

Orthohepevirus B ''Orthohepevirus'' is a genus of viruses assigned to the family ''Hepeviridae''. ''Orthohepevirus'' is a fairly isolated viral genus in which the virions are characterized by round, non-enveloped and isometry, isometric capsids with a diameter of ...

'', which was previously known as the avian hepatitis E virus, '' Orthohepevirus C'', and '' Orthohepevirus D''.

History

Hepatitis E was first isolated in 1990. It was thought to be restricted to humans until 1997 when it was isolated from pigs. The first isolation from birds was in 2001.

Evolution

One study has suggested that this species may have originated in birds and then spread to bats and other mammalian species.

References

External links

ICTV Online (10th) Report ''Hepeviridae''

Hepeviridae Virus genera {{Virus-stub