Editing RNA virus (section)

{{Short description|Subclass of viruses}}
{{Use dmy dates|date=December 2020}}
{{Update|taxonomy in baltimore sections [ICTV release 2018b→2019]|date=January 2021}}
[[File:18 2014 1695 Fig1 HTML.webp|thumb|Taxonomy and replication strategies of different types of RNA viruses]]
An '''RNA virus''' is a [[virus]] characterized by a ribonucleic acid ([[RNA]]) based [[genome]].<ref>{{cite book |last1=Wagner |first1=Edward K. |last2=Hewlett |first2=Martinez J. |title=Basic virology |url=https://archive.org/details/basicvirology0000wagn |access-date=30 March 2020 |year=1999 |publisher=Blackwell Science, Inc. |location=Malden, MA |isbn=0-632-04299-0 |page=249 }}</ref> The genome can be [[single-stranded]] RNA ([[ssRNA]]) or double-stranded ([[Double-stranded RNA|dsRNA]]).<ref name = Pattonrnav/> Notable human diseases caused by RNA viruses include [[influenza]], [[SARS]], [[MERS]], [[COVID-19]], [[Dengue virus]], [[hepatitis C]], [[hepatitis E]], [[West Nile fever]], [[Ebola virus disease]], [[rabies]], [[polio]], [[mumps]], and [[measles]].

All known RNA viruses, that is viruses that use a homologous RNA-dependent polymerase for replication, are categorized by the [[International Committee on Taxonomy of Viruses]] (ICTV) into the realm ''[[Riboviria]]''.<ref>{{cite journal |title=The new scope of virus taxonomy: partitioning the virosphere into 15 hierarchical ranks |journal=Nature Microbiology |date=May 2020 |volume=5 |issue=5 |pages=668–674 |doi=10.1038/s41564-020-0709-x|pmid=32341570 |doi-access=free |author1=International Committee on Taxonomy of Viruses Executive Committee |pmc=7186216 }}</ref>  This includes RNA viruses belonging to ''Group III'', ''Group IV'' or ''Group V'' of the [[Virus classification#Baltimore classification|Baltimore classification]] system as well as ''Group VI. Group VI'' viruses are [[retrovirus]]es, viruses with RNA genetic material that use [[DNA]] intermediates in their [[Viral life cycle|life cycle]] including [[HIV-1]] and [[HIV-2]] which cause [[AIDS]].

The majority of such RNA viruses fall into the kingdom ''[[Orthornavirae]]'' and the rest have a positioning [[Incertae sedis|not yet defined]].<ref name=ortho>TaxoProp [https://ictv.global/taxonomy/taxondetails?taxnode_id=201907198 2019.006G]</ref> The realm does not contain all RNA viruses: ''[[Deltavirus]]'', ''[[Avsunviroidae]]'', and ''[[Pospiviroidae]]'' are taxa of RNA viruses that were mistakenly included in 2019,{{efn|1=This inclusion was due to TaxoProp [https://ictv.global/taxonomy/taxondetails?taxnode_id=201907095 2017.006G], which proposed ''Riboviria''. The confusion might be due to the TaxoProp's reference to a "monophyly of all RNA viruses", improperly termed as it was only demonstrated with RdRP. On the other hand, the proposed definition of ''Riboviria'' did correctly mention RdRP
.}} but corrected in 2020.<ref>TaxoProp [https://ictv.global/taxonomy/taxondetails?taxnode_id=201905347 2019.009G]</ref>