Orthohepevirus is a genus of viruses assigned to the family Hepeviridae.[3]Orthohepevirus is a fairly isolated viral genus in which the virions are characterized by round, non-enveloped and isometriccapsids with a diameter of 27–34 nm. The hepatitis E virus belongs this genus as the species Orthohepevirus A[3]
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.[3]
Taxonomy
Viruses from this genus have been isolated from a variety of mammals (including rodents, mustelids and bats) as well as birds.[3][4][5] At least three variants of avian hepatitis E virus have been isolated from birds.[6]
A Hepatitis E-like virus has been isolated from a Swedish moose.[7] This virus is quite distinct from the other known Hepatitis E viruses.[3]
Hepatitis E was first isolated in 1990. It was thought to be restricted to humans until 1997 when it was isolated from pigs.[8] The first isolation from birds was in 2001.[9]
Evolution
One study has suggested that this species may have originated in birds and then spread to bats and other mammalian species.[4]
References
^Purdy, Michael A.; et al. (June 2014). "New Classification Scheme for Hepeviridae"(PDF). International Committee on Taxonomy of Viruses (ICTV). Retrieved 1 May 2019. The change from the current usage of Hepevirus to Orthohepevirus for avian and mammalian HEVs and Piscihepevirus for trout HEVs is used.
^Marek A, Bilic I, Prokofieva I, Hess M (2010). "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. doi:10.1016/j.vetmic.2010.03.014. PMID20399575.
^Zhao Q, Sun Y, Zhou E (2012). "[Detection and description of avian hepatitis E virus isolated in China—a review]". Wei Sheng Wu Xue Bao (in Chinese). 52 (3): 279–85. PMID22712397.