RNA virus
Encyclopedia
An RNA virus is a virus
that has RNA
(ribonucleic acid) as its genetic material. This nucleic acid
is usually single-stranded RNA (ssRNA) but may be double-stranded RNA (dsRNA). The ICTV
classifies RNA viruses as those that belong to Group III, Group IV or Group V of the Baltimore classification system of classifying viruses, and does not consider viruses with DNA intermediates as RNA viruses. Notable human diseases caused by RNA viruses include SARS, influenza
, hepatitis C
and HIV
.
Another term for RNA viruses that explicitly excludes retrovirus
es is ribovirus.
and positive-sense
, or ambisense RNA viruses. Positive-sense viral RNA is similar to mRNA and thus can be immediately translated
by the host cell. Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase
before translation. As such, purified RNA of a positive-sense virus can directly cause infection though it may be less infectious than the whole virus particle. Purified RNA of a negative-sense virus is not infectious by itself as it needs to be transcribed
into positive-sense RNA, however each virion can be transcribed to several positive-sense RNAs. Ambisense RNA viruses resemble negative-sense RNA viruses, except they also translate genes from the positive strand.
represent a diverse group of viruses that vary widely in host range (humans, animals, plants, fungi, and bacteria
), genome
segment number (one to twelve), and virion organization (T-number, capsid
layers, or turrets). Members of this group include the rotavirus
es, renowned globally as the most common cause of gastroenteritis
in young children, and bluetongue virus, an economically important pathogen of cattle and sheep. In recent years, remarkable progress has been made in determining, at atomic and subnanometeric levels, the structures of a number of key viral proteins and of the virion capsids of several dsRNA viruses, highlighting the significant parallels in the structure and replicative processes of many of these viruses.
rates compared to DNA virus
es, because viral RNA polymerases lack the proof-reading ability of DNA polymerase
s. This is one reason why it is difficult to make effective vaccines to prevent diseases caused by RNA viruses.
Retrovirus
es also have a high mutation rate even though their DNA intermediate integrates into the host genome (and is thus subject to host DNA proofreading once integrated), because errors during reverse transcription are embedded into both strands of DNA before integration.
Some genes of RNA virus are important to the viral replication cycles and mutations are not tolerated. For example, the region of the hepatitis C virus
genome that encodes the core protein is highly conserved
, because it contains an RNA structure involved in an internal ribosome entry site
.
Retrovirus
es (Group VI) have a single-stranded RNA genome but are generally not considered RNA viruses because they use DNA intermediates to replicate. Reverse transcriptase
, a viral enzyme that comes from the virus itself after it is uncoated, converts the viral RNA into a complementary strand of DNA, which is copied to produce a double stranded molecule of viral DNA. After this DNA is integrated
, expression of the encoded genes may lead the formation of new virions.
I. Bymoviruses, comoviruses, nepoviruses, nodaviruses, picornaviruses, potyviruses, sobemoviruses and a subset of luteoviruses (beet western yellows virus and potato leafroll virus) - the picorna like group (Picornavirata).
II. Carmoviruses, dianthoviruses, flaviviruses, pestiviruses, tombusviruses, single-stranded RNA bacteriophages, hepatitis C virus and a subset of luteoviruses (barley yellow dwarf virus) - the flavi like group (Flavivirata).
III. Alphaviruses, carlaviruses, furoviruses, hordeiviruses, potexviruses, rubiviruses, tobraviruses, tricornaviruses, tymoviruses, apple chlorotic leaf spot virus, beet yellows virus and hepatitis E virus - the alpha like group (Rubivirata).
The alpha like groups can be further divided into three clades: the rubi-like, tobamo-like, and tymo-like viruses.
Additional work has identified five groups of positive stranded RNA viruses containing four, three, three, three and one order(s) respectively. These fourteen orders contain 31 virus families (including 17 families of plant viruses) and 48 genera (including 30 genera of plant viruses). This analysis suggests that alphaviruses and flaviviruses can be separated into two families - the Togaviridae and Flaviridae respectively - but suggests that other taxonomic assignments, such as the pestiviruses, hepatitis C virus, rubiviruses, hepatitis E virus and arteriviruses, may be incorrect. The coronaviruses and toroviruses appear to be distinct families in distinct orders and not distinct genera of the same family as currently classified. The luteoviruses appear to be two families rather than one and apple chlorotic leaf spot virus appears not to be a closterovirus but a new genus of the Potexviridae.
This analysis also suggests that the dsRNA viruses are not closely related to each other but instead belong to four additional classes - Birnaviridae, Cystoviridae, Partitiviridae and Reoviridae - and one additional order (Totiviridae) of one of the classes of positive ssRNA viruses in the same subphylum as the positive strand RNA viruses.
These proposals were based on an analysis of the RNA polymerases and are still under consideration. To date they have not been broadly accepted because of doubts over the suitability of a single gene to determine the taxonomy of the clade.
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Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
that has RNA
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
(ribonucleic acid) as its genetic material. This nucleic acid
Nucleic acid
Nucleic acids are biological molecules essential for life, and include DNA and RNA . Together with proteins, nucleic acids make up the most important macromolecules; each is found in abundance in all living things, where they function in encoding, transmitting and expressing genetic information...
is usually single-stranded RNA (ssRNA) but may be double-stranded RNA (dsRNA). The ICTV
International Committee on Taxonomy of Viruses
The International Committee on Taxonomy of Viruses is a committee which authorizes and organizes the taxonomic classification of viruses. They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to...
classifies RNA viruses as those that belong to Group III, Group IV or Group V of the Baltimore classification system of classifying viruses, and does not consider viruses with DNA intermediates as RNA viruses. Notable human diseases caused by RNA viruses include SARS, influenza
Influenza
Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...
, hepatitis C
Hepatitis C
Hepatitis C is an infectious disease primarily affecting the liver, caused by the hepatitis C virus . The infection is often asymptomatic, but chronic infection can lead to scarring of the liver and ultimately to cirrhosis, which is generally apparent after many years...
and HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
.
Another term for RNA viruses that explicitly excludes retrovirus
Retrovirus
A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA...
es is ribovirus.
Single-stranded RNA viruses and RNA Sense
RNA viruses can be further classified according to the sense or polarity of their RNA into negative-senseSense (molecular biology)
In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...
and positive-sense
Sense (molecular biology)
In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...
, or ambisense RNA viruses. Positive-sense viral RNA is similar to mRNA and thus can be immediately translated
Translation (genetics)
In molecular biology and genetics, translation is the third stage of protein biosynthesis . In translation, messenger RNA produced by transcription is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein...
by the host cell. Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase
RNA polymerase
RNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...
before translation. As such, purified RNA of a positive-sense virus can directly cause infection though it may be less infectious than the whole virus particle. Purified RNA of a negative-sense virus is not infectious by itself as it needs to be transcribed
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
into positive-sense RNA, however each virion can be transcribed to several positive-sense RNAs. Ambisense RNA viruses resemble negative-sense RNA viruses, except they also translate genes from the positive strand.
Double-stranded RNA viruses
The double-stranded (ds)RNA virusesDouble-stranded RNA viruses
Double-stranded RNA viruses are a diverse group of viruses that vary widely in host range , genome segment number , and virion organization...
represent a diverse group of viruses that vary widely in host range (humans, animals, plants, fungi, and bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
), genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
segment number (one to twelve), and virion organization (T-number, capsid
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
layers, or turrets). Members of this group include the rotavirus
Rotavirus
Rotavirus is the most common cause of severe diarrhoea among infants and young children, and is one of several viruses that cause infections often called stomach flu, despite having no relation to influenza. It is a genus of double-stranded RNA virus in the family Reoviridae. By the age of five,...
es, renowned globally as the most common cause of gastroenteritis
Gastroenteritis
Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...
in young children, and bluetongue virus, an economically important pathogen of cattle and sheep. In recent years, remarkable progress has been made in determining, at atomic and subnanometeric levels, the structures of a number of key viral proteins and of the virion capsids of several dsRNA viruses, highlighting the significant parallels in the structure and replicative processes of many of these viruses.
Mutation rates
RNA viruses generally have very high mutationMutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
rates compared to DNA virus
DNA virus
A DNA virus is a virus that has DNA as its genetic material and replicates using a DNA-dependent DNA polymerase. The nucleic acid is usually double-stranded DNA but may also be single-stranded DNA . DNA viruses belong to either Group I or Group II of the Baltimore classification system for viruses...
es, because viral RNA polymerases lack the proof-reading ability of DNA polymerase
DNA polymerase
A DNA polymerase is an enzyme that helps catalyze in the polymerization of deoxyribonucleotides into a DNA strand. DNA polymerases are best known for their feedback role in DNA replication, in which the polymerase "reads" an intact DNA strand as a template and uses it to synthesize the new strand....
s. This is one reason why it is difficult to make effective vaccines to prevent diseases caused by RNA viruses.
Retrovirus
Retrovirus
A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA...
es also have a high mutation rate even though their DNA intermediate integrates into the host genome (and is thus subject to host DNA proofreading once integrated), because errors during reverse transcription are embedded into both strands of DNA before integration.
Some genes of RNA virus are important to the viral replication cycles and mutations are not tolerated. For example, the region of the hepatitis C virus
Hepatitis C virus
Hepatitis C virus is a small , enveloped, positive-sense single-stranded RNA virus of the family Flaviviridae...
genome that encodes the core protein is highly conserved
Conserved sequence
In biology, conserved sequences are similar or identical sequences that occur within nucleic acid sequences , protein sequences, protein structures or polymeric carbohydrates across species or within different molecules produced by the same organism...
, because it contains an RNA structure involved in an internal ribosome entry site
Internal ribosome entry site
An internal ribosome entry site, abbreviated IRES, is a nucleotide sequence that allows for translation initiation in the middle of a messenger RNA sequence as part of the greater process of protein synthesis...
.
Replication
Animal RNA viruses are classified into three distinct groups depending on their genome and mode of replication (and the numerical groups based on the older Baltimore classification):- Double-stranded RNA virusesDouble-stranded RNA virusesDouble-stranded RNA viruses are a diverse group of viruses that vary widely in host range , genome segment number , and virion organization...
(Group III) contain from one to a dozen different RNA molecules, each of which codes for one or more viral proteins. - Positive-sense ssRNA viruses (Group IV) have their genome directly utilized as if it were mRNA, producing a single protein which is modified by host and viral proteins to form the various proteins needed for replication. One of these includes RNA-dependent RNA polymeraseRNA-dependent RNA polymeraseRNA-dependent RNA polymerase , , or RNA replicase, is an enzyme that catalyzes the replication of RNA from an RNA template...
, which copies the viral RNA to form a double-stranded replicative form, in turn this directs the formation of new virions. - Negative-sense ssRNA viruses (Group V) must have their genome copied by an RNA polymeraseRNA polymeraseRNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...
to form positive-sense RNA. This means that the virus must bring along with it the RNA-dependent RNA polymeraseRNA-dependent RNA polymeraseRNA-dependent RNA polymerase , , or RNA replicase, is an enzyme that catalyzes the replication of RNA from an RNA template...
enzyme. The positive-sense RNA molecule then acts as viral mRNA, which is translated into proteins by the host ribosomes. The resultant protein goes on to direct the synthesis of new virions, such as capsidCapsidA capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
proteins and RNA replicase, which is used to produce new negative-sense RNA molecules.
Retrovirus
Retrovirus
A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA...
es (Group VI) have a single-stranded RNA genome but are generally not considered RNA viruses because they use DNA intermediates to replicate. Reverse transcriptase
Reverse transcriptase
In the fields of molecular biology and biochemistry, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase enzyme that transcribes single-stranded RNA into single-stranded DNA. It also helps in the formation of a double helix DNA once the RNA has been reverse...
, a viral enzyme that comes from the virus itself after it is uncoated, converts the viral RNA into a complementary strand of DNA, which is copied to produce a double stranded molecule of viral DNA. After this DNA is integrated
Integrase
Retroviral integrase is an enzyme produced by a retrovirus that enables its genetic material to be integrated into the DNA of the infected cell...
, expression of the encoded genes may lead the formation of new virions.
Classification
Classification of the positive strand RNA viruses is based on the RNA dependent RNA polymerase. Three groups have been recognised:I. Bymoviruses, comoviruses, nepoviruses, nodaviruses, picornaviruses, potyviruses, sobemoviruses and a subset of luteoviruses (beet western yellows virus and potato leafroll virus) - the picorna like group (Picornavirata).
II. Carmoviruses, dianthoviruses, flaviviruses, pestiviruses, tombusviruses, single-stranded RNA bacteriophages, hepatitis C virus and a subset of luteoviruses (barley yellow dwarf virus) - the flavi like group (Flavivirata).
III. Alphaviruses, carlaviruses, furoviruses, hordeiviruses, potexviruses, rubiviruses, tobraviruses, tricornaviruses, tymoviruses, apple chlorotic leaf spot virus, beet yellows virus and hepatitis E virus - the alpha like group (Rubivirata).
The alpha like groups can be further divided into three clades: the rubi-like, tobamo-like, and tymo-like viruses.
Additional work has identified five groups of positive stranded RNA viruses containing four, three, three, three and one order(s) respectively. These fourteen orders contain 31 virus families (including 17 families of plant viruses) and 48 genera (including 30 genera of plant viruses). This analysis suggests that alphaviruses and flaviviruses can be separated into two families - the Togaviridae and Flaviridae respectively - but suggests that other taxonomic assignments, such as the pestiviruses, hepatitis C virus, rubiviruses, hepatitis E virus and arteriviruses, may be incorrect. The coronaviruses and toroviruses appear to be distinct families in distinct orders and not distinct genera of the same family as currently classified. The luteoviruses appear to be two families rather than one and apple chlorotic leaf spot virus appears not to be a closterovirus but a new genus of the Potexviridae.
This analysis also suggests that the dsRNA viruses are not closely related to each other but instead belong to four additional classes - Birnaviridae, Cystoviridae, Partitiviridae and Reoviridae - and one additional order (Totiviridae) of one of the classes of positive ssRNA viruses in the same subphylum as the positive strand RNA viruses.
These proposals were based on an analysis of the RNA polymerases and are still under consideration. To date they have not been broadly accepted because of doubts over the suitability of a single gene to determine the taxonomy of the clade.
Group III - dsRNA viruses
- Family BirnaviridaeBirnaviridaeThe birnaviridae are a family of viruses, including the following genera:*Genus Aquabirnavirus; type species: Infectious pancreatic necrosis virus*Genus Avibirnavirus; type species: Infectious bursal disease virus...
- Family Chrysoviridae
- Family Cystoviridae
- Family Endornaviridae
- Family Hypoviridae
- Family PartitiviridaePartitiviridaePartitiviridae are plant and fungi group III viruses with double stranded RNA genomes. Their name comes from the Latin partitius which means divided and they are called this as they have segmented genomes....
- Family Picobirnaviridae
- Family ReoviridaeReoviridaeReoviridae is a family of viruses that can affect the gastrointestinal system and respiratory tract. Viruses in the family Reoviridae have genomes consisting of segmented, double-stranded RNA...
- includes RotavirusRotavirusRotavirus is the most common cause of severe diarrhoea among infants and young children, and is one of several viruses that cause infections often called stomach flu, despite having no relation to influenza. It is a genus of double-stranded RNA virus in the family Reoviridae. By the age of five,... - Family TotiviridaeTotiviridaeThe Totiviridae are a family of viruses. They are non enveloped, icosahedral viruses. The viron is composed of a single capsid protein and are ~40 nanometers in diameter. The capsid has a T=2 symmetry....
- Unassigned genera
- EndornavirusEndornavirusThe Endornavirus is a genus of plant viruses. The non-enveloped viral capsid holds a non-segmented single molecule of double-stranded RNA, 14000-18000 nucleotides long...
- VaricosavirusVaricosavirusThe viral genus Varicosavirus is a plant virus associated with the swelling it causes in plant vein tissues. It is a double stranded RNA virus with no specific assigned family. Infection occurs through soil by the spores of the fungus Olpidium brassicae....
- Endornavirus
- Unassigned species
- Sclerotinia sclerotiorum debilitation-associated virus
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Group IV - positive-sense ssRNA viruses
- Order NidoviralesNidoviralesThe Nidovirales are an order of viruses with animal hosts. It includes the families Coronaviridae, Arterivirus and Roniviridae.-Virology:...
- Family ArteriviridaeArterivirusArterivirus is a genus of virus, with type species equine arteritis virus. In 1996, the family Arteriviridae was included within the order Nidovirales. Arteriviruses are small, enveloped, animal viruses with an icosahedral core containing a positive-sense RNA genome...
- Family CoronaviridaeCoronaviridaeCoronaviruses are enveloped, single-stranded, positive-sense RNA viruses with club-shaped surface about 120-160 nm in diameter that resemble a “corona”.-Virology:...
- includes CoronavirusCoronavirusCoronaviruses are species in the genera of virus belonging to the subfamily Coronavirinae in the family Coronaviridae. Coronaviruses are enveloped viruses with a positive-sense single-stranded RNA genome and a helical symmetry. The genomic size of coronaviruses ranges from approximately 16 to 31...
, SARSSevere acute respiratory syndromeSevere Acute Respiratory Syndrome is a respiratory disease in humans which is caused by the SARS coronavirus . Between November 2002 and July 2003 an outbreak of SARS in Hong Kong nearly became a pandemic, with 8,422 cases and 916 deaths worldwide according to the WHO... - Family RoniviridaeOkavirusOkavirus is a genus of virus. It is the only genus in the family in the order Nidovirales. Okaviruses infect crustaceans, mostly prawns.The type species is Gill-associated virus....
- Family Arteriviridae
- Order PicornaviralesPicornaviralesThe Picornavirales are an order of viruses with vertebrate, insects and plant hosts.This group consists of viruses which have sense single stranded RNA genomes....
- Family Bacillariornaviridae
- Family CaliciviridaeCaliciviridaeThe Caliciviridae family are a family of viruses, members of Class IV of the Baltimore scheme. They are positive-sense, single stranded RNA which is non-segmented. The caliciviruses have been found in a number of organisms such as humans, cattle, pigs, cats, chickens, reptiles, dolphins and...
- includes Norwalk virus - Family DicistroviridaeDicistroviridaeThe Dicistroviridae are a family of Group IV insect-infecting viruses. Some of the insects commonly infected by dicistroviruses include aphids, leafhoppers, flies, bees, ants, silkworms.-Taxonomy:...
- Family IflaviridaeIflaviridaeThe Iflaviridae are a family of Group IV insect-infecting viruses. Some of the insects commonly infected by dicistroviruses include aphids, leafhoppers, flies, bees, ants, silkworms, wasps....
- Family Labyrnaviridae
- Family Marnaviridae
- Family Picornaviridae - includes PoliovirusPoliovirusPoliovirus, the causative agent of poliomyelitis, is a human enterovirus and member of the family of Picornaviridae.Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA genome that is about 7500 nucleotides long. The viral particle is...
, the common coldRhinovirusHuman rhinoviruses are the most common viral infective agents in humans and are the predominant cause of the common cold. Rhinovirus infection proliferates in temperatures between 33–35 °C , and this may be why it occurs primarily in the nose...
virus, Hepatitis AHepatitis AHepatitis A is an acute infectious disease of the liver caused by the hepatitis A virus , an RNA virus, usually spread the fecal-oral route; transmitted person-to-person by ingestion of contaminated food or water or through direct contact with an infectious person...
virus - Family PotyviridaePotyviridaeThe Potyviridae are a family of plant viruses. They are . Their genome is composed of positive-sense RNA which is surrounded by a protein coat made up of a single viral encoded protein called a capsid. All induce the formation of virus inclusion bodies called in their hosts...
- Family SecoviridaeSecoviridaeThe Secoviridae are a family of Group IV plant-infecting viruses in the order Picornavirales.They include the following genera:*Cheravirus*Sadwavirus*Sequivirus*Torradovirus*Waikavirus...
includes subfamily ComovirinaeComoviridaeThe Comovirinae are a subfamily within the family Secoviridae in the order of Picornavirales, including the following genera:*Genus Comovirus; type species: Cowpea mosaic virus*Genus Fabavirus; type species: Broad bean wilt virus 1... - Family SequiviridaeSequiviridaeThe Sequiviridae are a family of viruses, including the following genera:*Genus Sequivirus; type species: Parsnip yellow fleck virus*Genus Waikavirus; type species: Rice tungro spherical virus-External links:*...
- Order TymoviralesTymoviralesThe Tymovirales are a newly established order of viruses in the 2009 classification with four genera.This group consists of viruses which have sense single stranded RNA genomes without DNA intermediates.-External links:*ICTV Virus Taxonomy 2009...
- Family AlphaflexiviridaeAlphaflexiviridaeAlphaflexiviridae are single-stranded positive sense RNA plant viruses, belonging to the order Tymovirales and thus to group IV of the Baltimore classification of viruses.The Alphaflexiviridae family include the following genera:...
- Family BetaflexiviridaeBetaflexiviridaeBetaflexiviridae are single-stranded positive sense RNA plant viruses, belonging to the order Tymovirales and thus to group IV of the Baltimore classification of viruses.-Taxonomy:The Betaflexiviridae family include the following genera:...
- Family GammaflexiviridaeGammaflexiviridaeGammaflexiviridae are single-stranded positive sense RNA plant viruses, belonging to the order Tymovirales and thus to group IV of the Baltimore classification of viruses.The Gammaflexiviridae family include the following genera:...
- Family TymoviridaeTymoviridaeTymoviridae are monopartite single-stranded positive sense RNA plant viruses, belonging to group IV of the Baltimore classification of viruses...
- Family Alphaflexiviridae
- Unassigned
- Family Alvernaviridae
- Family Astroviridae
- Family BarnaviridaeBarnavirusBarnavirus is a genus of virus, with type species Mushroom bacilliform virus.-External links:*...
- Family BromoviridaeBromoviridaeThe Bromoviridae are a family of plant viruses, including the following genera:*Genus Alfamovirus; type species: Alfalfa mosaic virus*Genus Anulavirus; type species: Pelargonium zonate spot virus...
- Family ClosteroviridaeClosteroviridaeThe Closteroviridae are a family of viruses plant viruses with filamentous, helically constructed particles showing distinct cross-banding and varying in length from 650 nanometers to over 2000 nm. The genome is a single strand of positive sense RNA whose size varies from 13 - 19...
- Family FlaviviridaeFlaviviridaeThe Flaviviridae are a family of viruses that are primarily spread through arthropod vectors . The family gets its name from Yellow Fever virus, a type virus of Flaviviridae; flavus means yellow in Latin...
- includes Yellow feverYellow feverYellow fever is an acute viral hemorrhagic disease. The virus is a 40 to 50 nm enveloped RNA virus with positive sense of the Flaviviridae family....
virus, West Nile virusWest Nile virusWest Nile virus is a virus of the family Flaviviridae. Part of the Japanese encephalitis antigenic complex of viruses, it is found in both tropical and temperate regions. It mainly infects birds, but is known to infect humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels, domestic...
, Hepatitis C virusHepatitis C virusHepatitis C virus is a small , enveloped, positive-sense single-stranded RNA virus of the family Flaviviridae...
, Dengue feverDengue feverDengue fever , also known as breakbone fever, is an infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles...
virus - Family LeviviridaeLeviviridaeThe Leviviridae are a family of viruses, including the following genera:*Genus Levivirus; type species: Enterobacteria phage MS2*Genus Allolevivirus; type species: Enterobacteria phage Qβ-External links:*...
- Family LuteoviridaeLuteoviridaeThe Luteoviridae are a family of viruses, including the following genera:*Genus Luteovirus; type species: Barley yellow dwarf virus-PAV*Genus Polerovirus; type species: Potato leafroll virus...
- includes Barley yellow dwarf virus - Family NarnaviridaeNarnaviridaeThe Narnaviridae are a family of positive single stranded RNA viruses. Uniquely among viruses they lack a protein coat.-Virology:The genome is unipartate and between 2.3 and 3.5 kilobases in length. It encodes a single gene - the RNA dependent RNA polymerase. This protein is associated with the...
- Family NodaviridaeNodaviridaeNodaviridae is a family of RNA viruses.-Virology:The virus is not enveloped and has an isocahedral capsid ranging from 29 to 35 nm in diameter...
- Family TetraviridaeTetraviridaeThe Tetraviridae are a family of viruses infecting Moths and Butterflies, including the following genera:*Genus Betatetravirus; type species: Nudaurelia capensis β virus*Genus Omegatetravirus; type species: Nudaurelia capensis ω virus...
- Family TogaviridaeTogaviridaeThe Togaviridae are a family of viruses, including the following genera:* Genus Alphavirus; type species: Sindbis virus, Eastern equine encephalitis virus, Western equine encephalitis virus, Venezuelan equine encephalitis virus, Ross River virus, O'nyong'nyong virus, Chikungunya* Genus Rubivirus;...
- includes RubellaRubellaRubella, commonly known as German measles, is a disease caused by the rubella virus. The name "rubella" is derived from the Latin, meaning little red. Rubella is also known as German measles because the disease was first described by German physicians in the mid-eighteenth century. This disease is...
virus, Ross River virusRoss River virusRoss River virus is a small encapsulated single-strand RNA alphavirus endemic to Australia, Papua New Guinea and other islands in the South Pacific. It is responsible for a type of mosquito-borne non-lethal but debilitating tropical disease known as Ross River fever, previously termed "epidemic...
, Sindbis virusSindbis virusSindbis Virus is a member of the Togaviridae family, in the alphavirus subfamily. The virus was first isolated in 1952 in Cairo, Egypt. The virus is transmitted by mosquitoes SINV causes sindbis fever in humans and the symptoms include arthralgia, rash and malaise...
, Chikungunya virus - Family TombusviridaeTombusviridaeTombusviridae is a family of single-stranded positive sense RNA plant viruses. The name is derived from the type species of the Tombusvirus genus, Tomato bushy stunt virus...
- Family VirgaviridaeVirgaviridaeVirgaviridae is a family of positive single stranded RNA viruses that infect plants. All virons in this family are rod shaped. There are currently six genera in this family.The name of the family is derived from the Latin word virga ....
-
- Unassigned genera
- Genus BenyvirusBenyvirusThe viral genus Benyvirus has no family.It is characterized by a positive-stranded single stranded RNA genome that is rod-shaped and non-enveloped in nature...
- Genus HepevirusHepevirusHepevirus is a viral genus with no currently assigned family. This genus is not to be confused with the Herpesvirus family. Hepevirus is a fairly isolated viral genus in which the virions are characterized by round, non-enveloped and isometric capsids with a diameter of 27-34 nm. The gene is...
- includes Hepatitis EHepatitis EHepatitis E is a viral hepatitis caused by infection with a virus called hepatitis E virus . HEV is a positive-sense single-stranded RNA icosahedral virus with a 7.5 kilobase genome. HEV has a fecal-oral transmission route. It is one of five known hepatitis viruses: A, B, C, D, and E...
virus - Genus IdaeovirusIdaeovirusThe Idaeovirus refers to a genus of a plant virus with currently no assigned family or order. Virus consists of a non-enveloped, icosahedral capsid with a diameter of 33 nm. The viral gene is segmented into 3 parts of positive sense, single stranded RNA of about 8600 nucleotides in length...
- Genus OurmiavirusOurmiavirusThe Ourmiavirus is a genus of a virus with no family. Virions are encapsulated, non-enveloped, elongated and shows polyhedral symmetry with a length of 26-76 nm and a width of 18-26 nm. The genome is segmented into three segments or four segments of linear, positive-sense,...
- Genus SobemovirusSobemovirusThe Sobemovirus is a genus of a virus with no family. Virion capsids are non-enveloped, round and isometric, with a diameter of 25-33 nm. The genome is a single piece of linear, positive-sense, single-stranded RNA, 4100-5700 nucleotides in length.....
- Genus UmbravirusUmbravirusThe genus Umbravirus includes plant viruses. The genus has not yet been assigned to a family but it is closely allied to the Tombusviridae.Umbraviruses do not encode their own coat protein, but use the coat proteins of 'assistor viruses' from the family Luteoviridae to produce virions, allowing...
- Genus Benyvirus
- Unassigned genera
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- Unassigned species
- Chronic bee paralysis associated satellite virus
- Extra small virus
- Unassigned species
Group V - negative-sense ssRNA viruses
- Order MononegaviralesMononegaviralesThe order Mononegavirales is the taxonomic home of numerous related viruses. Members of the order that are commonly known are, for instance, Ebola virus, human respiratory syncytial virus, measles virus, mumps virus, Nipah virus, and rabies virus. All of these viruses cause significant disease in...
- Family BornaviridaeBorna diseaseBorna disease is an infectious neurological syndrome of warm-blooded animals, caused by Borna disease virus, which causes abnormal behaviour and fatality....
- Borna disease virus - Family FiloviridaeFiloviridaeThe family Filoviridae is the taxonomic home of several related viruses that form filamentous virions. Two members of the family that are commonly known are Ebola virus and Marburg virus. Both viruses, and some of their lesser known relatives, cause severe disease in humans and nonhuman primates in...
- includes EbolaEbolaEbola virus disease is the name for the human disease which may be caused by any of the four known ebolaviruses. These four viruses are: Bundibugyo virus , Ebola virus , Sudan virus , and Taï Forest virus...
virus, Marburg virusMarburg virusMarburg virus disease is the name for the human disease caused by any of the two marburgviruses Marburg virus and Ravn virus... - Family Paramyxoviridae - includes MeaslesMeaslesMeasles, also known as rubeola or morbilli, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses...
virus, Mumps virusMumps virusMumps virus is the causative agent of mumps, a well-known common childhood disease characterised by swelling of the parotid glands and other epithelial tissues, causing high morbidity and in some cases more serious complications such as deafness...
, Nipah virus, Hendra virus - Family RhabdoviridaeRhabdoviridaeRhabdoviruses are viruses belonging to the family Rhabdoviridae, which is in the order Mononegavirales. The name is derived from the Greek rhabdos meaning rod referring to the shape of the viral particles. Rhabdoviruses infect a broad range of hosts throughout the animal and plant kingdoms...
- includes RabiesRabiesRabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...
virus
- Family Bornaviridae
- Unassigned families:
- Family Arenaviridae - includes Lassa virus
- Family BunyaviridaeBunyaviridaeBunyaviridae is a family of negative-stranded RNA viruses. Though generally found in arthropods or rodents, certain viruses in this family occasionally infect humans. Some of them also infect plants....
- includes HantavirusHantavirusHantaviruses are negative sense RNA viruses in the Bunyaviridae family. Humans may be infected with hantaviruses through rodent bites, urine, saliva or contact with rodent waste products...
, Crimean-Congo hemorrhagic feverCrimean-Congo hemorrhagic feverCrimean–Congo hemorrhagic fever is a widespread tick-borne viral disease, a zoonosis of domestic animals and wild animals, that may affect humans. The pathogenic virus, especially common in East and West Africa, is a member of the Bunyaviridae family of RNA viruses. Clinical disease is rare in... - Family Ophioviridae
- Family OrthomyxoviridaeOrthomyxoviridaeThe Orthomyxoviridae are a family of RNA viruses that includes five genera: Influenzavirus A, Influenzavirus B, Influenzavirus C, Isavirus and Thogotovirus. A sixth has recently been described...
- includes InfluenzaInfluenzaInfluenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...
viruses
- Unassigned genera:
- Genus Deltavirus
- Genus NyavirusNyavirusThe creation of a genus Nyavirus was suggested in 2009 for two viruses, Nyamanini virus and Midway virus . According to the suggestion, both viruses would be assigned to species of the same name that would constitute the genus....
- includes Nyamanini and Midway viruses - Genus TenuivirusTenuivirusTenuivirus ls a name of genera of plant viruses. The type member is "Rice Stripe Virus." Other members of this genera include "Maize Stripe Virus," "Rice Hoja Blanca Virus'," and "Iranian Wheat Strip Virus." These plant viruses cause diseases in their host plants...
- Unassigned species:
- Taastrup virus
Source:
See also
- Virus classificationVirus classificationVirus classification is the process of naming viruses and placing them into a taxonomic system. Similar to the classification systems used for cellular organisms, virus classification is the subject of ongoing debate and proposals. This is mainly due to the pseudo-living nature of viruses, which...
- Viral replication
- Positive/negative-senseSense (molecular biology)In molecular biology and genetics, sense is a concept used to compare the polarity of nucleic acid molecules, such as DNA or RNA, to other nucleic acid molecules...
- Animal virusesAnimal virologyThe study of animal viruses is important from a veterinary viewpoint and many of these viruses cause diseases that are economically devastating. Many animal viruses are also important from a human medical perspective...
- Double-stranded RNA virusesDouble-stranded RNA virusesDouble-stranded RNA viruses are a diverse group of viruses that vary widely in host range , genome segment number , and virion organization...
- RetrovirusRetrovirusA retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA...
- DNA viruses