Avihepadnavirus


Avihepadnavirus is a genus of viruses, in the family Hepadnaviridae. Birds serve as natural hosts. There are five species in this genus. Diseases associated with this genus include: hepatitis, hepatocellular carcinomas, and cirrhosis.

Taxonomy

The genus contains the following species, listed by scientific name and followed by the exemplar virus of the species:Avihepadnavirus anatigruidae, Duck hepatitis B virus - also includes SHGHBV, SGHBV, CHBV, and RGHBVAvihepadnavirus ciconiardeae, Heron hepatitis B virus - also includes STHBVAvihepadnavirus psittaunius, Parrot hepatitis B virus 1Avihepadnavirus psittaduorum, Parrot hepatitis B virus 2Avihepadnavirus bonicursoris, Elegant-crested tinamou hepatitis B virus

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.
GenusStructureSymmetryCapsidGenomic arrangementGenomic segmentation
AvihepadnavirusIcosahedralT=4Non-envelopedCircularMonopartite

Life cycle

Viral replication is nucleo-cytoplasmic. Replication follows the dsDNA 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. 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.
GenusHost detailsTissue tropismEntry detailsRelease detailsReplication siteAssembly siteTransmission
AvihepadnavirusBirdsHepatocytesCell receptor endocytosisBuddingNucleusCytoplasmVertical: parental; sex; blood