{Reference Type}: Journal Article {Title}: ICTV Virus Taxonomy Profile: Kolmioviridae 2024. {Author}: Kuhn JH;Babaian A;Bergner LM;Dény P;Glebe D;Horie M;Koonin EV;Krupovic M;Paraskevopoulou S;de la Peña M;Smura T;Hepojoki J; {Journal}: J Gen Virol {Volume}: 105 {Issue}: 2 {Year}: 2024 02 {Factor}: 5.141 {DOI}: 10.1099/jgv.0.001963 {Abstract}: Kolmioviridae is a family for negative-sense RNA viruses with circular, viroid-like genomes of about 1.5-1.7 kb that are maintained in mammals, amphibians, birds, fish, insects and reptiles. Deltaviruses, for instance, can cause severe hepatitis in humans. Kolmiovirids encode delta antigen (DAg) and replicate using host-cell DNA-directed RNA polymerase II and ribozymes encoded in their genome and antigenome. They require evolutionary unrelated helper viruses to provide envelopes and incorporate helper virus proteins for infectious particle formation. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Kolmioviridae, which is available at ictv.global/report/kolmioviridae.