Parechovirus | |
---|---|
Virus classification | |
(unranked): | Virus |
Realm: | Riboviria |
Kingdom: | Orthornavirae |
Phylum: | Pisuviricota |
Class: | Pisoniviricetes |
Order: | Picornavirales |
Family: | Picornaviridae |
Genus: | Parechovirus |
Species | |
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Parechovirus is a genus of viruses in the family Picornaviridae . Humans, ferrets, and various rodents serve as natural hosts. The genus currently consists of six accepted species. Human parechoviruses may cause gastrointestinal or respiratory illness in infants, and they have been implicated in cases of myocarditis and encephalitis. [1]
Eighteen types of human parechovirus have been identified: human parechovirus 1 (HPeV1, formerly echovirus 22), human parechovirus 2 (formerly echovirus 23), and HPeV3 to HPeV18. [2] [3] [4] [5] A total of 15 genotypes are currently recognised. [6]
The ICTV recognises the following six species: [1] [7]
An additional two species are recognised by Picornaviridae.com but not by the ICTV: [7]
Parechoviruses 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 7.3kb in length. [9]
Genus | Structure | Symmetry | Capsid | Genomic arrangement | Genomic segmentation |
---|---|---|---|---|---|
Parechovirus | Icosahedral [9] | Pseudo T=3 | Non-enveloped | Linear | Monopartite |
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. The virus exits the host cell by lysis, and viroporins. [10]
Genus | Host details | Tissue tropism | Entry details | Release details | Replication site | Assembly site | Transmission |
---|---|---|---|---|---|---|---|
Parechovirus | Humans | Respiratory tract; gastrointestinal tract | Cell receptor endocytosis | Lysis | Cytoplasm | Cytoplasm | Unknown |
Human parechoviruses cause mild, gastrointestinal or respiratory illness, but have been implicated in cases of myocarditis and encephalitis. Human parechoviruses are commonly spread and more than 95% of human cases are infected early in life, within two to five years of age. [11] [12] Parechovirus B has been proposed as a zoonotic virus, associated with diabetes and intrauterine fetal death in humans. [13] [14] However, the data regarding these features are currently limited and need to be confirmed. Parechovirus is a Biosafety Level 2 organism.[ citation needed ]
The first parechoviruses (E22 and E23) were isolated in 1956, and recognized as a new genus in 1996. [15] [16] Parechovirus B was first isolated from bank voles (Myodes glareolus, formerly Clethrionomys glareolus) in the mid-1990s. [17] Human parechovirus type 3 (HPeV3) was found in at least 20 U.S. young infants in 2014. Those numbers include a set of identical triplets from central Wisconsin, who contracted the virus and were diagnosed nearly two months later after a flurry of tests, as this was the first known case in those health systems. [18] The 2014 outbreak is a higher number than expected, and is thought to be linked to maternal-fetal transmission. [19]
The rhinovirus is a positive-sense, single-stranded RNA virus belonging to the genus Enterovirus in the family Picornaviridae. Rhinovirus is the most common viral infectious agent in humans and is the predominant cause of the common cold.
Coxsackieviruses are a few related enteroviruses that belong to the Picornaviridae family of nonenveloped, linear, positive-sense single-stranded RNA viruses, as well as its genus Enterovirus, which also includes poliovirus and echovirus. Enteroviruses are among the most common and important human pathogens, and ordinarily its members are transmitted by the fecal–oral route. Coxsackieviruses share many characteristics with poliovirus. With control of poliovirus infections in much of the world, more attention has been focused on understanding the nonpolio enteroviruses such as coxsackievirus.
Orthohantavirus is a genus of single-stranded, enveloped, negative-sense RNA viruses in the family Hantaviridae within the order Bunyavirales. Members of this genus may be called orthohantaviruses or simply hantaviruses.
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.
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Rubella virus (RuV) is the pathogenic agent of the disease rubella, transmitted only between humans via the respiratory route, and is the main cause of congenital rubella syndrome when infection occurs during the first weeks of pregnancy.
Enterovirus is a genus of positive-sense single-stranded RNA viruses associated with several human and mammalian diseases. Enteroviruses are named by their transmission-route through the intestine.
Bunyavirales is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class Ellioviricetes. The name Bunyavirales derives from Bunyamwera, where the original type species Bunyamwera orthobunyavirus was first discovered. Ellioviricetes is named in honor of late virologist Richard M. Elliott for his early work on bunyaviruses.
Birnaviridae is a family of double-stranded RNA viruses. Salmonid fish, birds and insects serve as natural hosts. There are currently 11 species in this family, divided among seven genera. Diseases associated with this family include infectious pancreatic necrosis in salmonid fish, which causes significant losses to the aquaculture industry, with chronic infection in adult salmonid fish and acute viral disease in young salmonid fish.
An arenavirus is a bi- or trisegmented ambisense RNA virus that is a member of the family Arenaviridae. These viruses infect rodents and occasionally humans. A class of novel, highly divergent arenaviruses, properly known as reptarenaviruses, have also been discovered which infect snakes to produce inclusion body disease. At least eight arenaviruses are known to cause human disease. The diseases derived from arenaviruses range in severity. Aseptic meningitis, a severe human disease that causes inflammation covering the brain and spinal cord, can arise from the lymphocytic choriomeningitis virus. Hemorrhagic fever syndromes, including Lassa fever, are derived from infections such as Guanarito virus, Junin virus, Lassa virus, Lujo virus, Machupo virus, Sabia virus, or Whitewater Arroyo virus. Because of the epidemiological association with rodents, some arenaviruses and bunyaviruses are designated as roboviruses.
The bank vole is a small vole with red-brown fur and some grey patches, with a tail about half as long as its body. A rodent, it lives in woodland areas and is around 100 millimetres (3.9 in) in length. The bank vole is found in much of Europe and in northwestern Asia. It is native to Great Britain but not to Ireland, where it has been accidentally introduced, and has now colonised much of the south and southwest.
Hepacivirus is a genus of positive-strand RNA viruses in the family Flaviviridae. The hepatitis C virus (HCV), in species Hepacivirus C, infects humans and is associated with hepatitis and hepatocellular carcinoma. There are fourteen species in the genus which infect a range of other vertebrate.
Cardiovirus are a group of viruses within order Picornavirales, family Picornaviridae. Vertebrates serve as natural hosts for these viruses.
Murine coronavirus (M-CoV) is a virus in the genus Betacoronavirus that infects mice. Belonging to the subgenus Embecovirus, murine coronavirus strains are enterotropic or polytropic. Enterotropic strains include mouse hepatitis virus (MHV) strains D, Y, RI, and DVIM, whereas polytropic strains, such as JHM and A59, primarily cause hepatitis, enteritis, and encephalitis. Murine coronavirus is an important pathogen in the laboratory mouse and the laboratory rat. It is the most studied coronavirus in animals other than humans, and has been used as an animal disease model for many virological and clinical studies.
Parechovirus B, formerly called the Ljungan virus, was first discovered in the mid-1990s after being isolated from a bank vole near the Ljungan river in Medelpad county, Sweden. It has since been established that Parechovirus B, which is also found in several places in Europe and America, causes serious illness in wild as well as laboratory animals. Several scientific articles have recently reported findings indicating that Parechovirus B is associated with malformations, intrauterine fetal death, and sudden infant death syndrome in humans. In addition, studies are being conducted worldwide to investigate the possible connection of the virus to diabetes, neurological and other illnesses in humans.
Kobuvirus is a genus of viruses in the order Picornavirales, in the family Picornaviridae. Humans and cattle serve as natural hosts. There are six species in this genus. Diseases associated with this genus include: gastroenteritis. The genus was named because of the virus particles' lumpy appearance by electron microscopy; "kobu" means "knob" in Japanese.
The Human Parechovirus 1 cis regulatory element is an RNA element which is located in the 5'-terminal 112 nucleotides of the genome of human parechovirus 1 (HPeV1). The element consists of two stem-loop structures together with a pseudoknot. Disruption of any of these elements impairs both viral replication and growth.
Gyrovirus is a genus of viruses, in the family Anelloviridae. Until 2011, chicken anemia virus was the only Gyrovirus identified, but since then gyroviruses have also been identified in humans. Diseases associated with this genus include: chicken infectious anemia, which is associated with depletion of cortical thymocytes and erythroblastoid cells.
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Echovirus 9 is a serotype of echovirus. When first discovered, it was labelled as a coxsackie A virus, A23. It was later discovered that A23 was an echovirus antigenically identical to the already-known echovirus 9.