Subfamily: Alphairidovirinae


Subfamily: Alphairidovirinae

Distinguishing features

Viruses within the subfamily infect primarily ectothermic vertebrates, i.e., bony fish (superclass Osteichthyes), amphibians and reptiles. In addition, members of the subfamily display the following characteristics: (1) they encode a DNA methyltransferase and methylate cystosine residues within CpG dinucleotides (exception SGIV and GIV), (2) with the exception of most lymphocystiviruses, their genome sizes are generally smaller (103-140 kbp compared to ~200 kbp) and their G+C content higher (49-55% compared to 28-48%) than those of betairidoviruses.

Genus demarcation criteria

The three genera within the subfamily are distinguished by differences in sequence identity/similarity, phylogenetic relationships, host species, G+C content, and clinical manifestations of viral infection.