Orthohepadnavirus

Orthohepadnavirus is a genus of viruses in the family Hepadnaviridae, the genus that holds hepatitis B virus and its close relatives. Humans and other mammals serve as its natural hosts, and it contains 19 species, among them viruses of woodchucks, ground squirrels, domestic cats, equids, shrews, monkeys and many kinds of bat, some of the bat viruses having first been reported in 2013. Virions are enveloped and spherical with T=4 symmetry and a diameter of around 42 nanometres, and the circular genome of about 3.2 kilobases codes for seven proteins. Replication is nucleo-cytoplasmic and follows the dsDNA reverse transcription model, with translation by leaky scanning, and the virus leaves the cell by budding. It targets liver cells and spreads by sexual, blood and contact routes. Diseases associated with the genus include hepatitis, cirrhosis and, in chronic infections, hepatocellular carcinoma.