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Avihepatovirus A
''Avihepatovirus'' is a genus of viruses in the order ''Picornavirales'', in the family ''Picornaviridae''. Ducks and geese serve as natural hosts. There is only one species in this genus: ''Avihepatovirus A''. Diseases associated with this genus include: fatal hepatitis. Structure Viruses in ''Avihepatovirus'' are non-enveloped, with icosahedral, spherical, and round geometries, and T=pseudo3 symmetry. The diameter is around 30 nm. Genomes are linear and non-segmented, around 7.7kb in length. Life cycle Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment of the virus to host receptors, which mediates endocytosis. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. Translation takes place by ribosomal skipping. The virus exits the host cell by lysis, and viroporins. Ducks and geese serve as the natural host. Transmission routes are fecal-oral. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. 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,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i.e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picornavirales
''Picornavirales'' is an order of viruses with vertebrate, invertebrate, protist and plant hosts. The name has a dual etymology. First, ''picorna-'' is an acronym for poliovirus, insensitivity to ether, coxsackievirus, orphan virus, rhinovirus, and ribonucleic acid. Secondly, pico-, meaning extremely small, combines with RNA to describe these very small RNA viruses. The order comprises viruses that historically are referred to as picorna-like viruses. Characteristics The families within this order share a number of common features: * The virions are non- enveloped, icosahedral, and about 30 nanometers in diameter. * The capsid has a "pseudo T=3" structure, and is composed of 60 protomers each made of three similar-sized but nonidentical beta barrels. * The genome is made of one or a few single-stranded RNA(s) serving directly as mRNA, without overlapping open reading frames. * The genome has a small protein, VPg, covalently attached to its 5' end, and usually a poly-adenylat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picornaviridae
Picornaviruses are a group of related nonenveloped RNA viruses which infect vertebrates including fish, mammals, and birds. They are viruses that represent a large family of small, positive-sense, single-stranded RNA viruses with a 30 nm icosahedral capsid. The viruses in this family can cause a range of diseases including the common cold, poliomyelitis, meningitis, hepatitis, and paralysis. Picornaviruses constitute the family ''Picornaviridae'', order ''Picornavirales'', and realm '' Riboviria''. There are 158 species in this family, assigned to 68 genera. Notable examples are genera ''Enterovirus'' (including ''Rhinovirus'' and ''Poliovirus''), ''Aphthovirus'', ''Cardiovirus'', and ''Hepatovirus''. Etymology The name "picornavirus" has a dual etymology. Firstly, the name derives from ''picorna''- which is an acronym for "''p''oliovirus, ''i''nsensitivity to ether, ''c''oxsackievirus, ''o''rphan virus, ''r''hinovirus, and ribo''n''ucleic ''a''cid". Secondly, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turkey Viral Hepatitis
The aetiological agent of turkey viral hepatitis is a virus from the ''Picornaviridae'' family. The disease is restricted to turkeys and is highly contagious but usually subclinical. It is usually present in young birds under the age of 6 weeks. It has been seen in Canada, Italy, the US and the UK. Transmission is thought to be via the faeces and vertical transmission may also occur. __TOC__ Clinical signs and diagnosis Affected turkeys may show systemic signs such as anorexia, lethargy and death. Hepatic encephalopathy occurs secondary to liver involvement. Egg hatching and production can be affected. Diagnosis relies on the isolation of the virus from samples of internal organs or the faeces inoculated into embryonated chicken eggs. The main necropsy findings are multiple necrotic lesions on the liver and sometimes the spleen The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
