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Positive-strand RNA virus
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<p>Positive-strand RNA viruses (+ssRNA viruses) are a group of related <a href="/facts/Virus/mf88Bcbl">viruses</a> that have <a href="/facts/Sense_(molecular_biology)/hcKgNvy6">positive-sense</a>, single-stranded genomes made of <a href="/facts/Ribonucleic_acid/HxPeNfNj">ribonucleic acid</a>. The positive-sense genome can act as <a href="/facts/Messenger_RNA/oUL6qxQn">messenger RNA</a> (mRNA) and can be directly <a href="/facts/Translation_(biology)/JcPC1rth">translated</a> into viral proteins by the <a href="/facts/Host_cell/L6mop0kh">host cell's</a> <a href="/facts/Ribosome/CF2u2gtg">ribosomes</a>. Positive-strand RNA viruses encode an <a href="/facts/RNA-dependent_RNA_polymerase/UgPn4rjz">RNA-dependent RNA polymerase</a> (RdRp) which is used during replication of the genome to synthesize a negative-sense antigenome that is then used as a template to create a new positive-sense viral genome. </p><p>Positive-strand RNA viruses are divided between the phyla <i><a href="/facts/Kitrinoviricota/x0ceeDAA">Kitrinoviricota</a></i>, <i><a href="/facts/Lenarviricota/kaHSjwQB">Lenarviricota</a></i>, and <i><a href="/facts/Pisuviricota/SPAcFwMe">Pisuviricota</a></i> (specifically classes <i><a href="/facts/Pisoniviricetes/AU6dRE5G">Pisoniviricetes</a></i> and <i><a href="/facts/Stelpaviricetes/jBpx6pvK">Stelpavirictes</a></i>) all of which are in the kingdom <i><a href="/facts/Orthornavirae/qG4evU2T">Orthornavirae</a></i> and <a href="/facts/Realm_(virology)/7F5jI4Rn">realm</a> <i><a href="/facts/Riboviria/WBD92F1n">Riboviria</a></i>. They are <a href="/facts/Monophyly/pD8Yrrn6">monophyletic</a> and descended from a common RNA virus ancestor. In the <a href="/facts/Baltimore_classification/XTV7bbGJ">Baltimore classification</a> system, +ssRNA viruses belong to Group IV. </p><p>Positive-sense RNA viruses include <a href="/facts/Pathogen/axMXtV1M">pathogens</a> such as the <a href="/facts/Hepatitis_C_virus/DFUwAzlB">Hepatitis C virus</a>, <a href="/facts/West_Nile_virus/BU0j4uux">West Nile virus</a>, <a href="/facts/Dengue_virus/15cVKcHL">dengue virus</a>, and the <a href="/facts/MERS_coronavirus/a5LDpoW8">MERS</a>, <a href="/facts/SARS_coronavirus/jXYCe6w5">SARS</a>, and <a href="/facts/SARS-CoV-2/DxF8rDc1">SARS-CoV-2</a> <a href="/facts/Coronavirus/LvV5mvl9">coronaviruses</a>, as well as less clinically serious pathogens such as the coronaviruses and <a href="/facts/Rhinovirus/2jDL2oWU">rhinoviruses</a> that cause the <a href="/facts/Common_cold/fP9A03U9">common cold</a>. </p>