Iridoviridae is a family of viruses with double-stranded DNA genomes.Amphibia, fish, invertebrates, lepidoptera, and orthoptera insects serve as natural hosts. There are currently 12 species in this family, divided among two subfamilies and 5 genera.
A virus is a small infectious agent that replicates only inside the living cells of an organism. Viruses can infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.
Deoxyribonucleic acid is a molecule composed of two chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.
Lepidoptera is an order of insects that includes butterflies and moths. About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 per cent of the total described species of living organisms. It is one of the most widespread and widely recognizable insect orders in the world. The Lepidoptera show many variations of the basic body structure that have evolved to gain advantages in lifestyle and distribution. Recent estimates suggest the order may have more species than earlier thought, and is among the four most speciose orders, along with the Hymenoptera, Diptera, and Coleoptera.
The name is derived from Iris the Greek goddess of the rainbow. This name was chosen because of the "rainbow-like" iridescence observed in heavily infected insects and pelleted samples of invertebrate iridoviruses. It may refer to any member of the Iridoviridae family or a particular genus within Iridoviridae.
In Greek mythology, Iris is the personification and goddess of the rainbow and messenger of the gods.
Greece, officially the Hellenic Republic, also known as Hellas, is a country located in Southern and Southeast Europe. Its population is approximately 10.7 million as of 2018; Athens is the nation's capital and largest city, followed by Thessaloniki.
A goddess is a female deity. Goddesses have been linked with virtues such as beauty, love, motherhood and fertility. They have also been associated with ideas such as war, creation, and death.
Other species include the shrimp haemocyte iridescent virus.
The virions are icosahedral with triangulation number (T) = 189–217, 120–350 nm in diameter and made up of three domains: an outer proteinaceous capsid, an intermediate lipid membrane, and a central core containing DNA-protein complexes. Some of the viruses also have an outer envelope. The presence or absence of an envelope depends on whether they budded from the cell membrane (enveloped viruses) or were arranged in paracrystalline arrays within the host cell cytoplasm and then were released by cell lysis (unenveloped viruses).
The linear genome varies between 150 and 303 kilobases in length. It contains terminal and redundant sequences and is circularly permuted.
Members of this family differ in their degree of genome methylation. The genera Chloriridovirus and Iridovirus lack a highly methylated genome. Members of the Lymphocystivirus, Megalocytivirus, and Ranavirus genera have genomes with about 25% of their cytosine residues methylated by a virally encoded DNA methyltransferase.
|Genus||Structure||Symmetry||Capsid||Genomic arrangement||Genomic segmentation|
|Ranavirus||Polyhedral||T=133 or 147||Linear||Monopartite|
Similar to the herpes viruses, transcription occurs in three stages: immediate-early, delayed-early, and late. Positive induction and negative feedback mechanisms exist in each stage, mediated by products of the other stages.
Virus particles enter the cell and uncoating occurs. The viral DNA is transported to the host cell nucleus, where it is transcribed by host RNA polymerase II modified by the virus. Meanwhile, host macromolecular synthesis is stopped.
Parental DNA produces a genome which is then the template for replication in the cytoplasm. Large concatemers of viral DNA are formed by recombination in the cytoplasm. Packaging of the new genomes into virions occurs in the cytoplasm and the virus is released either by budding from the cell membrane or cell lysis.
|Genus||Host details||Tissue tropism||Entry details||Release details||Replication site||Assembly site||Transmission|
|Lymphocystivirus||Fish||None||Cell receptor endocytosis||Lysis; budding||Nucleus||Cytoplasm||Unknown|
|Megalocytivirus||Fish||None||Cell receptor endocytosis||Lysis; budding||Nucleus||Cytoplasm||Unknown|
|Ranavirus||Frogs; snakes||None||Cell receptor endocytosis||Lysis; budding||Nucleus||Cytoplasm||Contact|
|Iridovirus||Insects||None||Cell receptor endocytosis||Lysis; budding||Nucleus||Cytoplasm||Contact|
|Chloriridovirus||Diptera with aquatic larval stage, mainly mosquitoes||None||Cell receptor endocytosis||Budding||Nucleus||Cytoplasm||Unknown|
Little is known about the pathogenesis of iridoviruses. The pathogenesis is, however, temperature dependent and iridoviruses are thus confined to poikilothermic hosts.
Members of the Iridoviridae family infect mainly invertebrates, but also some vertebrate species such as fish, amphibians and reptiles.
Poxviridae is a family of viruses. Humans, vertebrates, and arthropods serve as natural hosts. There are currently 69 species in this family, divided among 28 genera, which are divided into two subfamilies. Diseases associated with this family include smallpox.
Parapoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Like all members of the family Poxviridae, they are oval, relatively large, double-stranded DNA viruses. Parapoxviruses have a unique spiral coat that distinguishes them from other poxviruses. Parapoxviruses infect vertebrates, including a wide selection of mammals, and humans.
Tectiviridae is a family of viruses with three genera. Gram-negative bacteria serve as natural hosts. There are currently four species in this genus including the type species Enterobacteria phage PRD1. Tectiviruses have no head-tail structure, but are capable of producing tail-like tubes of ~ 60×10 nm upon adsorption or after chloroform treatment. The name is derived from Latin tectus.
Ascoviridae is a family of double strand DNA viruses that infect primarily invertebrates, mainly noctuids and spodoptera species; it contains two genera, Ascovirus, which contains three species, and Toursvirus with a single species Diadromus pulchellus toursvirus. The type species of Ascovirus is Spodoptera frugiperda ascovirus 1a, which infects the army worm.
Yatapoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Monkeys and baboons serve as natural hosts. There are currently only two species in this genus including the type species Yaba monkey tumor virus. Diseases associated with this genus include: histiocytomas, tumor-like mass of mononuclear cells.
The Chordopoxvirinae are a subfamily of viruses in the family Poxviridae. Humans, vertebrates, and arthropods serve as natural hosts. Currently, 38 species are placed in this subfamily, divided among 10 genera. Diseases associated with this subfamily include smallpox.
Entomopoxvirinae is a subfamily of viruses, in the family Poxviridae. Insects, human, vertebrates, and arthropods serve as natural hosts. There are currently 31 species in this subfamily, divided among 3 genera. Diseases associated with this subfamily include: impairment of motility and development.
Yualikevirus is a genus of viruses in the family Siphoviridae, unassigned to a sub-family. Bacteria serve as the natural host, with transmission achieved through passive diffusion. There are currently three species in this genus, including the type species Pseudomonas phage Yua.
Alphaentomopoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Entomopoxvirinae. Coleoptera insects serve as natural hosts. There are currently seven species in this genus including the type species Melolontha melolontha entomopoxvirus.
Betaentomopoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Entomopoxvirinae. Lepidoptera and orthoptera insects serve as natural hosts. There are currently 16 species in this genus including the type species Amsacta moorei entomopoxvirus.
Cervidpoxvirus is a genus of viruses in the family Poxviridae in the subfamily Chordopoxvirinae. Deer serve as natural hosts. Currently only one species is placed in this genus: the type species Mule deerpox virus.
Gammaentomopoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Entomopoxvirinae. Lepidoptera and orthoptera insects serve as natural hosts. There are currently six species in this genus including the type species Chironomus luridus entomopoxvirus.
Leporipoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Lagomorphs and squirrels serve as natural hosts. There are currently four species in this genus including the type species Myxoma virus. Diseases associated with this genus include: myxomatosis.
Suipoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Swine serve as natural hosts. There is currently only one species in this genus: the type species Swinepox virus. Diseases associated with this genus include: asymptomatic skin disease.
Crocodylidpoxvirus is a genus of viruses, in the family Poxviridae, in the subfamily Chordopoxvirinae. Crocodiles serve as natural hosts. There is currently only one species in this genus: the type species Nile crocodilepox virus. Diseases associated with this genus include: nodular skin lesions in young animals. Symptoms vary from a nonfatal dermatitis to more severe disease characterized by ophthalmia, rhinitis resulting in asphyxia, and debilitating illness with stunting and high mortality.
MicrobiologyBytes: Iridoviruses, archived from the original on February 24, 2007, retrieved 2007-03-06
Viral Bioinformatics Resource Center & Viral Bioinformatics – Canada, University of Victoria, archived from the original on August 17, 2007, retrieved 2007-03-06