Orthohepevirus Explained

Orthohepevirus is a genus of viruses assigned to the family Hepeviridae.^[1] Orthohepevirus is a fairly isolated viral genus in which the virions are characterized by round, non-enveloped and isometric capsids 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 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 frames. 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.^{[2] [3]} At least three variants of avian hepatitis E virus have been isolated from birds.^[4]

A Hepatitis E-like virus has been isolated from a Swedish moose.^[5] This virus is quite distinct from the other known Hepatitis E viruses.

In total, the genus has four recognized species: Orthohepevirus A, Orthohepevirus B, 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.^[6] The first isolation from birds was in 2001.^[7]

Evolution

One study has suggested that this species may have originated in birds and then spread to bats and other mammalian species.^[2]

External links

• ICTV Online (10th) Report Hepeviridae
• Viralzone: Hepevirus

Notes and References

1. Web site: ICTV Online (10th) Report.
2. Drexler JF, Seelen A, Corman VM, Fumie Tateno A, Cottontail V, Melim Zerbinati R, Gloza-Rausch F, Klose SM, Adu-Sarkodie Y, Oppong SK, Kalko EK, Osterman A, Rasche A, Adam A, Müller MA, Ulrich RG, Leroy EM, Lukashev AN, Drosten C . Bats worldwide carry hepatitis E virus-related viruses that form a putative novel genus within the family Hepeviridae . J. Virol. . 86 . 17 . 9134–47 . 2012 . 22696648 . 3416139 . 10.1128/JVI.00800-12 .
3. Marek A, Bilic I, Prokofieva I, Hess M . Phylogenetic analysis of avian hepatitis E virus samples from European and Australian chicken flocks supports the existence of a different genus within the Hepeviridae comprising at least three different genotypes . Vet. Microbiol. . 145 . 1–2 . 54–61 . 2010 . 20399575 . 10.1016/j.vetmic.2010.03.014 .
4. Zhao Q, Sun Y, Zhou E . [Detection and description of avian hepatitis E virus isolated in China—a review] . Chinese . Wei Sheng Wu Xue Bao . 52 . 3 . 279–85 . 2012 . 22712397 .
5. Lin J, Norder H, Uhlhorn H, Belák S, Widén F . Novel hepatitis E like virus found in Swedish moose . J. Gen. Virol. . 95 . Pt 3 . 557–70 . 2014 . 24296469 . 3929172 . 10.1099/vir.0.059238-0 .
6. Meng XJ, Purcell RH, Halbur PG, Lehman JR, Webb DM, Tsareva TS, Haynes JS, Thacker BJ, Emerson SU . A novel virus in swine is closely related to the human hepatitis E virus . Proc. Natl. Acad. Sci. U.S.A. . 94 . 18 . 9860–5 . 1997 . 9275216 . 23282 . 10.1073/pnas.94.18.9860. 1997PNAS...94.9860M . free .
7. Haqshenas G, Shivaprasad HL, Woolcock PR, Read DH, Meng XJ . Genetic identification and characterization of a novel virus related to human hepatitis E virus from chickens with hepatitis-splenomegaly syndrome in the United States . J. Gen. Virol. . 82 . 10 . 2449–62 . 2001 . 11562538 . 10.1099/0022-1317-82-10-2449 . free .