The Anelloviridae are a recently discovered family of viruses . They are classified as a vertebrate viruses and have a non-enveloped capsid, which is round with isometric, icosahedral symmetry and has a triangulation number of 3. The Anelloviridae are a recently discovered family of viruses . They are classified as a vertebrate viruses and have a non-enveloped capsid, which is round with isometric, icosahedral symmetry and has a triangulation number of 3. The type species is torque teno virus (genus Alphatorquevirus), discovered in 1997.