Enterovirus

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Enterovirus
Virus classification
Group:Group IV ((+)ssRNA)
Order:Picornavirales
Family:Picornaviridae
Genus:Enterovirus
Type species
Enterovirus C
Species

Enterovirus A
Enterovirus B
Enterovirus C
Enterovirus D
Enterovirus E
Enterovirus F
Enterovirus G
Enterovirus H
Enterovirus J
Rhinovirus A
Rhinovirus B
Rhinovirus C

 
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Enterovirus
Virus classification
Group:Group IV ((+)ssRNA)
Order:Picornavirales
Family:Picornaviridae
Genus:Enterovirus
Type species
Enterovirus C
Species

Enterovirus A
Enterovirus B
Enterovirus C
Enterovirus D
Enterovirus E
Enterovirus F
Enterovirus G
Enterovirus H
Enterovirus J
Rhinovirus A
Rhinovirus B
Rhinovirus C

Enteroviruses are a genus of positive-sense single-stranded RNA viruses associated with several human and mammalian diseases. Serologic studies have distinguished 66 human enterovirus serotypes on the basis of antibody neutralization tests. Additional antigenic variants have been defined within several of the serotypes on the basis of reduced or nonreciprocal cross-neutralization between variant strains. On the basis of their pathogenesis in humans and animals, the enteroviruses were originally classified into four groups, polioviruses, Coxsackie A viruses (CA), Coxsackie B viruses (CB), and echoviruses, but it was quickly realized that there were significant overlaps in the biological properties of viruses in the different groups. Enteroviruses isolated more recently are named with a system of consecutive numbers: EV68, EV69, EV70, and EV71, etc.[1]

Enteroviruses affect millions of people worldwide each year, and are often found in the respiratory secretions (e.g., saliva, sputum, or nasal mucus) and stool of an infected person. Historically, poliomyelitis was the most significant disease caused by an enterovirus, poliovirus. There are 62 non-polio enteroviruses that can cause disease in humans: 23 Coxsackie A viruses, 6 Coxsackie B viruses, 28 echoviruses, and 5 other enteroviruses.[2] Poliovirus, as well as coxsackie and echovirus are spread through the fecal-oral route. Infection can result in a wide variety of symptoms ranging from mild respiratory illness (common cold), hand, foot and mouth disease, acute hemorrhagic conjunctivitis, aseptic meningitis, myocarditis, severe neonatal sepsis-like disease, and acute flaccid paralysis.[2]

Species and genetics[edit]

Enteroviruses are members of the picornavirus family, a large and diverse group of small RNA viruses characterized by a single positive-strand genomic RNA. All enteroviruses contain a genome of approximately 7,500 bases and are known to have a high mutation rate due to low-fidelity replication and frequent recombination.[3] After infection of the host cell, the genome is translated in a cap-independent manner into a single polyprotein, which is subsequently processed by virus-encoded proteases into the structural capsid proteins and the nonstructural proteins, which are mainly involved in the replication of the virus.[4]

The enterovirus genus includes the following twelve species:[5]

Within these twelve species are the serotypes:

Coxsackie and echovirus[edit]

Coxsackie viruses are a non-phylogenetic group.[7] Coxsackie A viruses are mainly associated with human hand, foot and mouth disease. Coxsackie B viruses can cause signs and symptoms, similar to a "cold", but these viruses also can lead to more serious diseases, including myocarditis (inflammation of the heart); pericarditis (inflammation of the sac lining the heart); meningitis (inflammation of the membranes that line the brain and spinal cord); and pancreatitis (inflammation of the pancreas).

Echoviruses are a cause of many of the nonspecific viral infections. It is mainly found in the intestine, and can cause nervous disorders.[citation needed] The usual symptoms of Coxsackie and echovirus are fever, mild rash, and mild upper respiratory tract (URT) illness.[citation needed]

Enterovirus 71[edit]

Main article: EV-71

Enterovirus 71 (EV-71) is notable as one of the major causative agents for hand, foot and mouth disease (HFMD), and is sometimes associated with severe central nervous system diseases.[8] EV71 was first isolated and characterized from cases of neurological disease in California in 1969.[9][10] To date, little is known about the molecular mechanisms of host response to EV71 infection, but increases in the level of mRNAs encoding chemokines, proteins involved in protein degradation, complement proteins, and proapoptotis proteins have been implicated.[11]

Poliovirus[edit]

Main article: Poliovirus

There are three serotypes of poliovirus, PV1, PV2, and PV3; each with a slightly different capsid protein. Capsid proteins define cellular receptor specificity and virus antigenicity. PV1 is the most common form encountered in nature; however, all three forms are extremely infectious.[12] Poliovirus can affect the spinal cord and cause poliomyelitis.

Polioviruses were formerly classified as a species belonging to the genus Enterovirus in the family Picornaviridae. The Poliovirus species has been eliminated from the genus Enterovirus. The following serotypes, Human poliovirus 1, Human poliovirus 2, and Human poliovirus 3, were assigned to the species Human enterovirus C, in the genus Enterovirus in the family Picornaviridae. The type species of the genus Enterovirus was changed from Poliovirus to Human enterovirus C. This has been ratified in April 2008.[13] The 39th Executive Committee (EC39) of the International Committee on Taxonomy of Viruses (ICTV) met in Canada during June 2007 with new taxonomic proposals.[14]
Two of the proposals with three changes were:

Proposals approved at the (EC39) meeting of 2007, were sent to members of ICTV via email for ratification and have become official taxonomy. There have been a total of 215 taxonomic proposals, which have been approved and ratified since the 8th ICTV Report of 2005.[17]
The ratification process was performed by email. The proposals were sent electronically via email on March 18, 2008 to ICTV members with a request to vote on whether to ratify the taxonomic proposals, with a 1-month deadline. The following are two of the taxonomic proposals with three changes that were ratified by ICTV members in April 2008:
Picornaviruses

The ICTVdb, International Committee on Taxonomy of Viruses data base, based on the ICTV Master Species List, 8th Report, June 2005 is obsolete.[18]

Rhinovirus[edit]

Main article: Rhinovirus

There are three species of Rhinoviruses: Human Rhinovirus A, Human Rhinovirus B, and Human Rhinovirus C which contain over 100 serotypes. Rhinoviruses are the most suspected causative agents of the common cold. This makes it difficult to develop a single vaccine against so many serotypes.

Diseases caused by enterovirus infection[edit]

Treatment[edit]

Treatment for enteroviral infection is mainly supportive. In cases of pleurodynia, treatment consists of analgesics to relieve the severe pain that occurs in patients with the disease; in some severe cases, opiates may be needed. Treatment for aseptic meningitis caused by enteroviruses is also mainly symptomatic. In patients with enteroviral carditis, treatment consists of the prevention and treatment of complications, such as arrhythmias, pericardial effusion, and cardiac failure. Other treatments that have been investigated for enteroviral carditis include intravenous immunoglobulin.[23]

References[edit]

  1. ^ Oberste MS, Maher K, Kilpatrick DR, Pallansch MA (1999). "Molecular Evolution of the Human Enteroviruses: Correlation of Serotype with VP1 Sequence and Application to Picornavirus Classification". J. Virol. 73 (3): 1941–8. PMC 104435. PMID 9971773. 
  2. ^ a b c CDC article Non-Polio Enterovirus Infections
  3. ^ Li L, He Y, Yang H, et al. (2005). "Genetic Characteristics of Human Enterovirus 71 and Coxsackievirus A16 Circulating from 1999 to 2004 in Shenzhen, People's Republic of China". J. Clin. Microbiol. 43 (8): 3835–9. doi:10.1128/JCM.43.8.3835-3839.2005. PMC 1233905. PMID 16081920. 
  4. ^ Merkle I, van Ooij MJ, van Kuppeveld FJ, et al. (2002). "Biological Significance of a Human Enterovirus B-Specific RNA Element in the 3′ Nontranslated Region". J. Virol. 76 (19): 9900–9. doi:10.1128/JVI.76.19.9900-9909.2002. PMC 136489. PMID 12208967. 
  5. ^ INTERNATIONAL COMMITTEE ON TAXONOMY OF VIRUSES (March 2010). ICTV 2009 MASTER SPECIES LIST VERSION 4. [dead link]
  6. ^ ICTV (March 2010). International Committee on Taxonomy of Viruses 2009 MASTER SPECIES LIST VERSION 4 Download. 
  7. ^ Santti, Juhana; Heli Harvala; Leena Kinnunen; Timo Hyypia (2000). "Molecular epidemiology and evolution of coxsackievirus A9" (PDF). Journal of General Virology 81 (Pt 5): 1361–1372. PMID 10769080. Retrieved 2009-08-09. 
  8. ^ Lin TY, Chu C, Chiu CH (2002). "Lactoferrin inhibits enterovirus 71 infection of human embryonal rhabdomyosarcoma cells in vitro". J. Infect. Dis. 186 (8): 1161–4. doi:10.1086/343809. PMID 12355368. 
  9. ^ Wang JR, Tuan YC, Tsai HP, Yan JJ, Liu CC, Su IJ (2002). "Change of Major Genotype of Enterovirus 71 in Outbreaks of Hand-Foot-and-Mouth Disease in Taiwan between 1998 and 2000". J. Clin. Microbiol. 40 (1): 10–5. doi:10.1128/JCM.40.1.10-15.2002. PMC 120096. PMID 11773085. 
  10. ^ Laboratory Investigation of a Suspected Enterovirus 71 Outbreak
  11. ^ Shih SR, Stollar V, Lin JY, Chang SC, Chen GW, Li ML (2004). "Identification of genes involved in the host response to enterovirus 71 infection". J. Neurovirol. 10 (5): 293–304. doi:10.1080/13550280490499551. PMID 15385252. 
  12. ^ Paul JR (1971). A History of Poliomyelitis. (Yale studies in the history of science and medicine). New Haven, Conn: Yale University Press. ISBN 0-300-01324-8. 
  13. ^ "ICTV Newsletter #6 2008". ICTV. February 2008. p. 1. 
  14. ^ Stanway, Glyn. "Template for Taxonomic Proposal to the ICTV Executive Committee To merge two existing Species". In Knowles, Nick. 2005.261-262V.04.Polio. ICTV. pp. 1–4. 
  15. ^ Stanway, Glyn. "Template for Taxonomic Proposal to the ICTV Executive Committee To merge two existing Species". In Knowles, Nick. 2005.263V.04.TypeSpEntero. ICTV. pp. 1–2. 
  16. ^ "ICTV Newsletter #7 2009". ICTV. October 2009. p. 1. 
  17. ^ INTERNATIONAL COMMITTEE ON TAXONOMY OF VIRUSES (20 March 2010). "ICTV 2009 MASTER SPECIES LIST VERSION 4". [dead link]
  18. ^ Seroka, Rachel (23 February 2014). "Mysterious polio-like illness found in 5 California children". American Academy of Neurology. Retrieved 24 February 2014. 
  19. ^ "Mysterious Polio-Like Illness Found in California Children". Voice of America. February 24, 2014. Retrieved 24 February 2014. 
  20. ^ Chia JKS et al. "Chronic fatigue syndrome is associated with chronic enterovirus infection of the stomach" J Clin Pathol 2007; doi:10.1136/jcp.2007.050054.
  21. ^ http://yle.fi/uutiset/finnish_team_makes_diabetes_vaccine_breakthrough/6893356
  22. ^ Schwartz, R.A. "Enteroviruses Treatment & Management". Medscape. 

External links[edit]