The Togaviridae are a family of viruses, including the following genera: This article is about biological infectious particles. ...

• 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
• Genus Rubivirus; type species: Rubella virus

The Togaviridae family belong to group IV of the Baltimore classification of viruses. The genome is linear, single-stranded, positive sense RNA that is 10,000-12,000 nucleotides long. The 5'-terminus carries a methylated nucleotide cap and the 3'-terminus has a polyadenylated tail, therefore resembling cellular mRNA. The virus is enveloped and forms spherical particles (65-70nm diameter), the capsid within is icosahedral, constructed of 240 monomers, having a triangulation number of 4. The receptors for binding are unknown, however the tropism is varied and it is known that the glycoprotein spikes act as attachment proteins. After virus attachment and entry into the cell, gene expression and replication takes place within the cytoplasm. In biology and immunology, an alphavirus (pronounced alph-AV-ir-rus) belongs to the group IV Togaviridae family of viruses, according to the system of classification based on viral genome composition introduced by David Baltimore in 1971. ... Sindbis Virus (SINV) is a member of the Togaviridae family, in the alphavirus subfamily. ... Eastern equine encephalomyelitis virus (EEE), commonly called sleeping sickness or Triple E, is a zoonotic alphavirus and arbovirus present in North, Central and South America and the Caribbean. ... Western equine encephalitis (WEE) is a relatively uncommon viral infection caused by the WEE virus, an Alphavirus of the family Togaviridae. ... Venezuelan equine encephalitis virus is a mosquito-borne viral pathogen that causes Venezuelan equine encephalitis or encephalomyelitis (VEE). ... Ross River virus (RRV) is an arbovirus of the genus Alphavirus. ... Onyongnyong virus was first isolated by the Uganda Virus Research Institute in Entebbe, Uganda. ... Warning: Wikipedia does not give medical advice. ... Rubella, commonly known as German measles, is a disease caused by the rubella virus. ... Look up Family in Wiktionary, the free dictionary. ... The Baltimore classification is a classification system which groups viruses into families depending on their type of genome (DNA, RNA, single-stranded (ss), double-stranded (ds) etc. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... Left: An RNA strand, with its nitrogenous bases. ... A nucleotide is an organic molecule consisting of a heterocyclic nucleobase (a purine or a pyrimidine), a pentose sugar (deoxyribose in DNA or ribose in RNA), and a phosphate or polyphosphate group. ... Methylation refers to the replacement of a hydrogen atom (H) with a methyl group (CH3), regardless of the substrate. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... The interaction of mRNA in a eukaryote cell. ... There are very few or no other articles that link to this one. ... For other uses, see sphere (disambiguation). ... A capsid is the outer shell of a virus. ... An icosahedron [ˌaıkəsəhiːdrən] noun (plural: -drons, -dra [-drə]) is a polyhedron having 20 faces. ... In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ... In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ... It has been suggested that chemotropism be merged into this article or section. ... N-linked protein glycosylation (N-glycosylation of N-glycans) at Asn residues (Asn-x-Ser/Thr motifs) in glycoproteins[1]. Glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbones. ... Cross section of cell with cytoplasm labeled at center right. ...

Genome replication

The non-structural proteins are encoded at the 5’ end, formed during the first of two characteristic rounds of translation. These proteins are originally translated as a polyprotein, which consequently undergo self cleavage, forming four non-structural proteins responsible for gene expression and replication. The formation of a sub-genomic fragment, encoding the structural proteins and a negative sense fragment, a template for further synthesis of positive sense RNA are the characteristic second phase of translation. Assembly takes place at the cell surface, where the virus buds from the cell, acquiring the envelope. The replication cycle is very fast, taking around 4 hours. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Look up translate in Wiktionary, the free dictionary. ... Look up cleavage in Wiktionary, the free dictionary. ... Gene expression, or simply expression, is the process by which the inheritable information which comprises a gene, such as the DNA sequence, is made manifest as a physical and biologically functional gene product, such as protein or RNA. Several steps in the gene expression process may be modulated, including the... DNA replication. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... High magnification view of a budding yeast Budding is the formation of a new organism by the protrusion of part of another organism. ... Replication may mean: In biology: Self-replication, when a molecule (or any other pattern) makes a copy of itself DNA replication, the act of copying the genetic material of a cell (DNA) to a daughter cell Semiconservative replication, mechanism of DNA replication Other: replication (computer science), the provision of redundant...

History

Initially the Togavirus family included what are now called the Flaviviruses, within the Alphavirus genus. The Flaviviruses were formed into their own family when sufficient differences with the Alphaviruses were noted. Genera Flavivirus Pestivirus Hepacivirus The Flaviviridae are a family of viruses that infect mammals. ... In biology and immunology, an alphavirus (pronounced alph-AV-ir-rus) belongs to the group IV Togaviridae family of viruses, according to the system of classification based on viral genome composition introduced by David Baltimore in 1971. ...

Early 1800s-Rubella is identified as a distinct disease

1930-Western Equine Encephalitis virus is first isolated in the United States (1st alphavirus ever isolated)

1933-Eastern Equine Encephalitis virus is first isolated in the United States.

1938-Venezuelan Equine Encephalitis is isolated.

1941-Western Equine Encephalitis epidemic is seen in the United States. It affects 300,000 horses and 3,336 humans.

1941-Normann Gregg notices large number of children with cataracts following a rubella outbreak. This and other defects are then categorized under the congenital rubella syndrome.

1942-Semliki Forest virus is isolated in Buliyama, Bwamba County, Uganda.

1952-Sindbis virus is isolated in the Sindbis health district, 40 miles north of Cairo, Egypt.

1959-Ross River virus is isolated from Aedes vigilax mosquitoes which were trapped at the Ross River in Australia.

1962-Rubella virus is isolated in culture.

1963-Ross River virus, which causes epidemic polyarthritis (mostly seen in Australia), is isolated by Doherty and colleagues.

1964-The last major epidemic of Rubella in the United States is seen. Approximately 20,000 infants are left with permanent damage following in-utero rubella exposure.

1969-Rubella vaccine is licensed

1971- Last epidemic of Venezuelan equine encephalitis is seen in horses in southern Texas.

1972- The rubella vaccine is combined with the measles and mumps vaccines to form the Measles/Mumps/Rubella (MMR) vaccine.

1986- Barmah Forest virus is identified as causing human disease in Australia.

1991-92- Most recent worldwide epidemic of rubella. Probably due to vaccine failures and missed vaccinations.

References

• University of Leicester, Microbiology
• Stanford University
• Murray, et al, Medical Microbiology, 5th Edition, Philadelphia, Elsevier Mosby 2005 ISBN 0-323-03325-3