Many distinct polyomaviruses infecting a variety of vertebrate hosts have recently been discovered, and their complete genome sequence could often be determined. To accommodate this fast-growing diversity, the International Committee on Taxonomy of Viruses (ICTV) <i>Polyomaviridae</i> Study Group designed a host- and sequence-based rationale for an updated taxonomy of the family <i>Polyomaviridae</i>. ...