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 that methylates cystosine residues within CpG dinucleotides (with the exception of SGIV and GIV), (2) with the exception of some lymphocystiviruses, their genomes are generally smaller (103–140 kbp compared to ~200 kbp) with a higher G+C content (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, phylogenetic relationships, host species, G+C content, and clinical manifestations of viral infection.