RNA Virus - Group IV - Positive-sense SsRNA Viruses

Positive-sense SsRNA Viruses

There are three orders and 30 families recognised in this group. In addition there are a number of unclassified species and genera.

A new family in the order Nidovirales - Mesoniviridae - with a new genus - Alphamesonivirus - has been proposed for the viruses Cavally virus and Nam Dinh virus has been proposed and awaits approval (or otherwise) by the ICTV.

Order Nidovirales
- Family Arteriviridae
- Family Coronaviridae - includes Coronavirus, SARS
- Family Roniviridae

Order Picornavirales

- Family Dicistroviridae
- Family Iflaviridae
- Family Marnaviridae
- Family Picornaviridae - includes Poliovirus, the common cold virus, Hepatitis A virus
- Family Secoviridae includes subfamily Comovirinae
- Genus Bacillariornavirus
- Genus Labyrnavirus

Order Tymovirales
- Family Alphaflexiviridae
- Family Betaflexiviridae
- Family Gammaflexiviridae
- Family Tymoviridae

Unassigned
- Family Alphatetraviridae
- Family Alvernaviridae
- Family Astroviridae
- Family Barnaviridae
- Family Bromoviridae
- Family Caliciviridae - includes Norwalk virus
- Family Carmotetraviridae
- Family Closteroviridae
- Family Flaviviridae - includes Yellow fever virus, West Nile virus, Hepatitis C virus, Dengue fever virus
- Family Leviviridae
- Family Luteoviridae - includes Barley yellow dwarf virus
- Family Narnaviridae
- Family Nodaviridae
- Family Permutotetraviridae
- Family Potyviridae
- Family Togaviridae - includes Rubella virus, Ross River virus, Sindbis virus, Chikungunya virus
- Family Tombusviridae
- Family Virgaviridae

- Unassigned genera
  - Genus Benyvirus
  - Genus Cilevirus
  - Genus Hepevirus - includes Hepatitis E virus
  - Genus Idaeovirus
  - Genus Ourmiavirus
  - Genus Polemovirus
  - Genus Sobemovirus
  - Genus Umbravirus

- Unassigned species
  - Botrytis virus F
  - Canine picodicistrovirus
  - Chronic bee paralysis associated satellite virus
  - Extra small virus
  - Heterocapsa circularisquama RNA virus
  - Le Blanc virus
  - Orsay virus
  - Santeuil virus