''Avihepadnavirus'' is a genus of

virus A virus is a wikt:submicroscopic, submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and ...

es, in the family ''

Hepadnaviridae ''Hepadnaviridae'' is a family of viruses. Humans, apes, and birds serve as natural hosts. There are currently 18 species in this family, divided among 5 genera. Its best-known member is hepatitis B virus. Diseases associated with this family i ...

''. Birds serve as natural hosts. There are three species in this genus. Diseases associated with this genus include:

hepatitis Hepatitis is inflammation of the liver parenchyma, liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), Anorexia (symptom), poor appetite ...

hepatocellular carcinoma Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and is currently the most common cause of death in people with cirrhosis. HCC is the third leading cause of cancer-related deaths worldwide. It occurs in th ...

s (chronic infections), and

cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is the impaired liver function caused by the formation of scar tissue known as fibrosis due to damage caused by liver disease. Damage causes tissue repai ...

Taxonomy

The genus contains the following species: * ''

Duck hepatitis B virus ''Duck hepatitis B virus'', abbreviated DHBV, is part of the genus '' Avihepadnavirus'' of the '' Hepadnaviridae'', and is the causal agent of duck hepatitis B. DHBV is a small DNA virus with a diameter of 40–45 nm. The viral envelope ...

'' * '' Heron hepatitis B virus'' * ''

Parrot hepatitis B virus Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genus (biology), genera comprising the order (biology), order Psittaciformes (), found mostly in tropics, tropical and subtropics, subtropical regions. The order ...

Structure

Viruses in the genus ''Avihepadnavirus'' 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.

Life cycle

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

ribosomal shunting Ribosome shunting is a mechanism of translation initiation in which ribosomes bypass, or "shunt over", parts of the 5' untranslated region to reach the start codon. However, a benefit of ribosomal shunting is that it can translate backwards allowing ...

. The virus exits the host cell by budding, and nuclear pore export. Birds serve as the natural host. Transmission routes are parental, sexual, and blood.

References

External links

ICTV Report: ''Hepadnaviridae''

{{Taxonbar, from=Q842413 Hepadnaviridae Virus genera