Viruses

A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 16,000 of the millions of virus species have been described in detail. The study of viruses is

thumb|Gamma phage, an example of virus particles (visualised by electron microscopy)

life that exists without a cellular structure, such as virusses, viroids, etc.

placeholder name that was adopted by the World Health Organization (WHO) in February 2018 on a shortlist of blueprint priority diseases to represent a hypothetical, unknown pathogen that could cause a future epidemic

virus classification system by David Baltimore consisting of 7 groups based on genome type (DNA or RNA), number of strands (single- or double-stranded), sense (positive or negative), and method of replication (through DNA or RNA intermediate)

300px|thumb|upright=1.6|Percentage of people infected with hepatitis C in 2015. The [[hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer (hepatocellular carcinoma, abbreviated HCC) and lymphomas in humans.]]

non-technical introduction to viruses

formation of biological viruses during the infection process in the target host cells

Influence of viruses and viral infections on human history

plant virus that causes the leaves to have a speckled appearance

Duplodnaviria is a realm of viruses that includes all double-stranded DNA viruses that encode the HK97 fold major capsid protein. The HK97 fold major capsid protein (HK97 MCP) is the primary component of the viral capsid, which stores the viral deoxyribonucleic acid (DNA). Viruses in the realm also share a number of other characteristics, such as an icosahedral capsid, an opening in the capsid called a portal, a protease enzyme that empties the inside of the capsid prior to DNA packaging, and a terminase enzyme that packages viral DNA into the capsid. There are three groups of viruses in the r

Revtraviricetes is a class of viruses that contains all viruses that encode a reverse transcriptase. The group includes all ssRNA-RT viruses (including the retroviruses) and dsDNA-RT viruses. It is the sole class in the phylum Artverviricota, which is the sole phylum in the kingdom Pararnavirae. The name of the group is a portmanteau of "reverse transcriptase" and -viricetes which is the suffix for a virus class.

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virus containing genetic material from other organisms

virus that is capable of infecting nerve cells

virus that is newly evolved or rapidly increasing in incidence or range

Pisuviricota is a phylum of RNA viruses that includes all positive-strand and double-stranded RNA viruses that infect eukaryotes and are not members of the phyla Kitrinoviricota, Lenarviricota or Duplornaviricota. The name of the group is a syllabic abbreviation of “picornavirus supergroup” with the suffix -viricota, indicating a virus phylum. Phylogenetic analyses suggest that Birnaviridae and Permutotetraviridae, both currently unassigned to a phylum in Orthornavirae, also belong to this phylum and that both are sister groups.

species of virus

Virivore (equivalently virovore) comes from the English prefix viro- meaning virus, derived from the Latin word for poison, and the suffix -vore from the Latin word vorare, meaning to eat, or to devour; therefore, a virivore is an organism that consumes viruses. Virivory is a well-described process in which organisms, primarily heterotrophic protists, consume viruses, though some metazoans are known to do so, as well.

Ribozyviria is a realm of satellite nucleic acids — infectious agents that resemble viruses, but cannot replicate without a helper virus. Established in ICTV TaxoProp 2020.012D, the realm is named after the presence of genomic and antigenomic ribozymes of the Deltavirus type. The agents in Ribozyviria are satellite nucleic acids, which are distinct from satellite viruses in that they do not encode all of their own structural proteins but require proteins from their helper viruses in order to assemble. Additional common features include a rod-like structure, an RNA-binding "delta antigen" encod

Cressdnaviricota is a phylum of viruses with small, circular single-stranded DNA genomes and encoding rolling circle replication-initiation proteins with the N-terminal HUH endonuclease and C-terminal superfamily 3 helicase domains. While the replication-associated proteins are homologous among viruses within the phylum, the capsid proteins are very diverse and have presumably been acquired from RNA viruses on multiple independent occasions. Nevertheless, all cressdnaviruses for which structural information is available appear to contain the jelly-roll fold.

REDIRECT Floreoviria

situation when a reservoir population with a high pathogen prevalence comes into contact with a novel host population, and may cause an epidemic in the latter

thumb|right|alt=Illustration of fur virus shapes in green|Illustration of different types of virion found in Bromoviridae, a family in the order Martellivirales Martellivirales is an order of viruses.

Pisoniviricetes is a class of positive-strand RNA viruses which infect eukaryotes. A characteristic of the group is a conserved 3C-like protease from the PA clan of proteases for processing the translated polyprotein. The name of the group is a portmanteau of member orders "picornavirales, sobelivirales, nidovirales" and -viricetes which is the suffix for a virus class.

transmission of an infectious agent between host organisms of two different species that may lead to a new outbreak

Alsuviricetes is a class of positive-strand RNA viruses which infect eukaryotes. The name of the group is a syllabic abbreviation of "alpha supergroup" with the suffix -viricetes indicating a virus class.

Papovaviricetes is a class of viruses. The class shares the name of an abolished family, Papovaviridae, which was split in 1999 into the two families Papillomaviridae and Polyomaviridae. The class was established in 2019 and takes its name from the former family.

Lenarviricota is a phylum of RNA viruses that includes all positive-strand RNA viruses that infect prokaryotes. Some members also infect eukaryotes. Most of these viruses do not have capsids, except for the genus Ourmiavirus. The name of the group is a syllabic abbreviation of the names of founding member families "Leviviridae and Narnaviridae" with the suffix -viricota, denoting a virus phylum.

Duplornaviricota is a phylum of RNA viruses, which contains all double-stranded RNA viruses, except for those in phylum Pisuviricota. Characteristic of the group is a viral capsid composed of 60 homo- or heterodimers of capsid protein on a pseudo-T=2 lattice. Duplornaviruses infect both prokaryotes and eukaryotes. The name of the group derives from Italian duplo which means double (a reference to double-stranded), rna for the type of virus, and -viricota which is the suffix for a virus phylum.

Preplasmiviricota is a phylum of viruses. Its name means "precursor of certain plasmids".

Botourmiaviridae is a family of positive-strand RNA viruses that infect plants and fungi. The family contains nine genera.

Kitrinoviricota is a phylum of RNA viruses that includes all positive-strand RNA viruses that infect eukaryotes and are not members of the phylum Pisuviricota or Lenarviricota. The name of the group derives from Greek κίτρινος (kítrinos), which means yellow (a reference to yellow fever virus), and -viricota, which is the suffix for a virus phylum.