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Viruses

Definition:	Minute infectious agents whose genomes are composed of DNA or RNA, but not both. They are characterized by a lack of independent metabolism and the inability to replicate outside living host cells.
Notes:	GEN or unspecified; prefer specific taxonomic group or genus; /drug eff: consider also ANTIVIRAL AGENTS; note X ref ONCOLYTIC VIRUSES: ONCOGENIC VIRUSES is available; do not confuse "slow viruses" with "latent viruses": slow cause dis with very long precl
Also Called:	Animal Viruses,Oncolytic Viruses,Zoophaginae

Viruses Categories.

	Arboviruses - Arthropod-borne viruses. A non-taxonomic designation for viruses that can replicate in both vertebrate hosts and arthropod vectors. Included are some members of the following families: ARENAVIRIDAE; BUNYAVIRIDAE; REOVIRIDAE; TOGAVIRIDAE; and FLAVIVIRIDAE. (From Dictionary of Microbiology and Molecular Biology, 2nd ed)
	Archaeal Viruses - Viruses whose hosts are in the domain ARCHAEA.
	Bacteriophages - Viruses whose hosts are bacterial cells.
	Defective Viruses - Viruses which lack a complete genome so that they cannot completely replicate or cannot form a protein coat. Some are host-dependent defectives, meaning they can replicate only in cell systems which provide the particular genetic function which they lack. Others, called SATELLITE VIRUSES, are able to replicate only when their genetic defect is complemented by a helper virus.
	DNA Viruses - Viruses whose nucleic acid is DNA.
	Helper Viruses - Viruses which enable defective viruses to replicate or to form a protein coat by complementing the missing gene function of the defective (satellite) virus. Helper and satellite may be of the same or different genus.
	Hepatitis Viruses - Any of the viruses that cause inflammation of the liver. They include both DNA and RNA viruses as well viruses from humans and animals.
	Insect Viruses - Viruses infecting insects, the largest family being BACULOVIRIDAE.
	Plant Viruses - Viruses parasitic on plants higher than bacteria.
	Proviruses - Duplex DNA sequences in eukaryotic chromosomes, corresponding to the genome of a virus, that are transmitted from one cell generation to the next without causing lysis of the host. Proviruses are often associated with neoplastic cell transformation and are key features of retrovirus biology.
	Reassortant Viruses - Viruses containing two or more pieces of nucleic acid (segmented genome) from different parents. Such viruses are produced in cells coinfected with different strains of a given virus.
	RNA Viruses - Viruses whose genetic material is RNA.
	Vertebrate Viruses - Viruses infecting man and other vertebrates.
	Virion - The infective system of a virus, composed of the viral genome, a protein core, and a protein coat called a capsid, which may be naked or enclosed in a lipoprotein envelope called the peplos.
	Viroids - A group of pathogens comprising the smallest known agents of infectious disease. They are unencapsulated and are capable of replicating autonomously in susceptible cells. Positively identified viroids composed of single-stranded RNA have been isolated from higher plants, but the existence of DNA viroids pathogenic to animals is suspected.
	Viruses, Unclassified - Viruses whose taxonomic relationships have not been established.

Viruses Definitions and Terms

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