Bullavirinae

Bullavirinae is a subfamily of viruses in the family "Microviridae". Enterobacteria serve as natural hosts. There are 14 species in this subfamily, organized into three genera.
Taxonomy.
The following genera and species are recognized:
Structure.
Viruses in Bullavirinae are non-enveloped, with icosahedral and round geometries, and T=1 symmetry. The diameter is around 30 nm. Genomes are circular, around 6.1kb in length.
Life cycle.
Viral replication is cytoplasmic. Entry into the host cell is achieved by pilus-mediated adsorption into the host cell. Replication follows the ssDNA rolling circle model. DNA-templated transcription is the method of transcription. The virus exits the host cell by bacteria lysis.
Enterobacteria serve as the natural host. Transmission routes are passive diffusion.