Review Article

Epidemiology, Phylogeny, and Evolution of Emerging Enteric Picobirnaviruses of Animal Origin and Their Relationship to Human Strains

Table 1

Key differences between Birnaviruses and Picobirnaviruses.

PropertiesPicobirnaviridae Birnaviridae

Hosts MammalsFish, chicken, and turkey
Virion size (diameter)35–40 nm65–70 nm
Capsid structureTriangulation of 1, 3 or 4 laevo symmetry
RNA polymeraseA-B-C motifsC-A-B motifs
Genome sizeSmaller segment—1.7 kb and larger segment—2.5 kbSmaller segment—2.8 kb and larger segment—3.3 kb
Genome organization (open reading frames)Two or three overlapping ORFs (segment 1)Single ORF