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Hepatitis B virus 1.jpg
TEM micrograph showing hepatitis B virions
Virus classification
Group: Group VII (dsDNA-RT)
Order: Unassigned
Family: Hepadnaviridae
Genus: Orthohepadnavirus

Orthohepadnavirus is a genus of viruses, in the family Hepadnaviridae. Human and mammals serve as natural hosts. There are currently five species in this genus including the type species Hepatitis B virus. Diseases associated with this genus include: hepatitis, hepatocellular carcinoma (chronic infections), cirrhosis.[1][2]


Viruses in Orthohepadnavirus are enveloped, with spherical geometries, and T=4 symmetry. The diameter is around 42 nm. Genomes are circular, around 3.2kb in length. The genome codes for 7 proteins.[1]

Genus Structure Symmetry Capsid Genomic arrangement Genomic segmentation
Orthohepadnavirus Icosahedral T=4 Non-enveloped Circular Monopartite

Life cycle[edit]

Viral replication is nucleo-cytoplasmic. Replication follows the dsDNA(RT) replication model. DNA-templated transcription, specifically dsDNA(RT) transcription, with some alternative splicing mechanism is the method of transcription. Translation takes place by leaky scanning. The virus exits the host cell by budding, and nuclear pore export. Human and mammals serve as the natural host. Transmission routes are sexual, blood, and contact.[1]

Genus Host details Tissue tropism Entry details Release details Replication site Assembly site Transmission
Orthohepadnavirus Humans; mammals Hepatocytes Cell receptor endocytosis Budding Nucleus Cytoplasm Vertical: parental; sex; blood


Group: ssRNA-RT



  1. ^ a b c "Viral Zone". ExPASy. Retrieved 15 June 2015. 
  2. ^ a b ICTV. "Virus Taxonomy: 2014 Release". Retrieved 15 June 2015. 

External links[edit]