[1] Although amniotes, especially mammals, were thought to serve as hosts, it has been recently suggested that these viruses might infect bacteria and possibly some other invertebrates.

[6] Picobirnaviruses were first detected in humans and black-footed pigmy rice rats in 1988.

[4] The capsid protein gene is encoded by the second open reading frame of the larger genomic segment 1.

[5][4] Picobirnaviruses were initially thought to belong to the family Birnaviridae, but later were confirmed to differ with respect to host, virion size, capsid, RNA-dependent RNA polymerase, genome size, and organization.

[9] The family Picobirnaviridae is now classified distinctly and composed of one genus Picobirnavirus, which has three species:[10]