The viruses assigned to a genus form a monophyletic clade in well-supported Maximum Likelihood or Maximum Clade Credibility trees using full-length L sequences. The subfamily includes 32 genera for viruses infecting only vertebrates, only invertebrates or vertebrate hosts and arthropod vectors. Various members may infect birds, reptiles, amphibians, non-dipteran insects, ticks, crustaceans or nematodes.
Genus demarcation criteria
Demarcation of genera is based upon considerations of significant differences in genome sequence and architecture, antigenicity and ecological properties (such as host range, pathobiology and transmission patterns).