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Parechovirus
Virus classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Orthornavirae
Phylum:	Pisuviricota
Class:	Pisoniviricetes
Order:	Picornavirales
Family:	Picornaviridae
Genus:	Parechovirus
Species
Parechovirus A Parechovirus B Parechovirus C Parechovirus D Parechovirus E Parechovirus F And see text

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.

Taxonomy

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. A total of 15 genotypes are currently recognised.

Species

The ICTV recognises the following six species:

• Parechovirus A (formerly Human parechovirus; human host)
• Parechovirus B (formerly Ljungan virus; rodent host)
• Parechovirus C (formerly Sebokele virus 1; rodent host)
• Parechovirus D (formerly Ferret parechovirus; carnivoran host)
• Parechovirus E
• Parechovirus F

An additional two species are recognised by Picornaviridae.com but not by the ICTV:

• Ljungan/Sebokele-like parechovirus (LCLPV) (falcon host, Hungary)
• Manhattan parechovirus (MPeV) (rodent host, United States)

Structure

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.

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. The virus exits the host cell by lysis, and viroporins.

Clinical information

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. Parechovirus B has been proposed as a zoonotic virus, associated with diabetes and intrauterine fetal death in humans. However, the data regarding these features are currently limited and need to be confirmed. Parechovirus is a Biosafety Level 2 organism.

History

The first parechoviruses (E22 and E23) were isolated in 1956, and recognized as a new genus in 1996. Parechovirus B was first isolated from bank voles (Myodes glareolus, formerly Clethrionomys glareolus) in the mid-1990s. 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. The 2014 outbreak is a higher number than expected, and is thought to be linked to maternal-fetal transmission.

References

1. ^ "ICTV Master Species List 2018a v1". International Committee on Taxonomy of Viruses. Archived from the original on March 14, 2019. Retrieved 15 December 2018.
2. Bissel, SJ; Auer, RN; Chiang, CH; Kofler, J; Murdoch, GH; Nix, WA; Painter, M; Richer, M; Sartelet, H; Wang, G; Wiley, CA (2015). "Human Parechovirus 3 Meningitis and Fatal Leukoencephalopathy". Journal of Neuropathology and Experimental Neurology. 74 (8): 767–777. doi:10.1097/NEN.0000000000000215. PMID 26115191.
3. Ito M, Yamashita T, Tsuzuki H, Takeda N, Sakae K (2004). "Isolation and identification of a novel human parechovirus". J. Gen. Virol. 85 (2): 391–398. doi:10.1099/vir.0.19456-0. PMID 14769896.
4. Al-Sunaidi M, Williams CH, Hughes PJ, Schnurr DP, Stanway G (2007). "Analysis of a new human parechovirus allows the definition of parechovirus types and the identification of RNA structural domains". J. Virol. 81 (2): 1013–21. doi:10.1128/JVI.00584-06. PMC 1797470. PMID 17005640.
5. Watanabe K, Oie M, Higuchi M, Nishikawa M, Fujii M (June 2007). "Isolation and characterization of novel human parechovirus from clinical samples". Emerg Infect Dis. 13 (6): 889–95. doi:10.3201/eid1306.060896. PMC 2792847. PMID 17553229.
6. "Virus Taxonomy: 2019 Release". talk.ictvonline.org. International Committee on Taxonomy of Viruses. Retrieved 7 May 2020.
7. Chieochansin T, Vichiwattana P, Korkong S, Theamboonlers A, Poovorawan Y (2011) Molecular epidemiology, genome characterization, and recombination event of human parechovirus. Virology
8. ^ "Parechovirus". Picornaviridae.com. Archived from the original on 12 March 2019. Retrieved 15 February 2019.
9. "Picornaviridae.com: Manhattan PeV gene sequences". Archived from the original on 2019-02-16. Retrieved 2019-02-15.
10. ^ Shakeel, Shabih; Westerhuis, Brenda M.; Ora, Ari; Koen, Gerrit; Bakker, Arjen Q.; Claassen, Yvonne; Wagner, Koen; Beaumont, Tim; Wolthers, Katja C.; Butcher, Sarah J. (2015). "Structural Basis of Human Parechovirus Neutralization by Human Monoclonal Antibodies". Journal of Virology. 89 (18): 9571–9580. doi:10.1128/JVI.01429-15. PMC 4542383. PMID 26157123.
11. "Viral Zone". ExPASy. Retrieved 15 June 2015.
12. Stanway G, Joki-Korpela P, Hyypiä T (2000). "Human parechoviruses--biology and clinical significance". Rev. Med. Virol. 10 (1): 57–69. doi:10.1002/(SICI)1099-1654(200001/02)10:1<57::AID-RMV266>3.0.CO;2-H. PMID 10654005. S2CID 1284023.
13. Joki-Korpela P, Hyypiä T (2001). "Parechoviruses, a novel group of human picornaviruses". Ann. Med. 33 (7): 466–71. doi:10.3109/07853890109002095. PMID 11680794. S2CID 37499760.
14. Niklasson B, Samsioe A, Papadogiannakis N, Kawecki A, Hörnfeldt B, Saade GR, Klitz W (2007). "Association of zoonotic Ljungan virus with intrauterine fetal deaths". Birth Defects Research Part A: Clinical and Molecular Teratology. 79 (6): 488–93. doi:10.1002/bdra.20359. PMID 17335057.
15. Niklasson B, Heller KE, Schonecker B, Bildsoe M, Daniels T, Hampe CS, Widlund P, Simonson WT, Schaefer JB, Rutledge E, Bekris L, Lindberg AM, Johansson S, Örtqvist E, Persson B, Lernmark Å (2003). "Development of type 1 diabetes in wild bank voles associated with islet autoantibodies and the novel ljungan virus". Int. J. Exp. Diabesity. Res. 4 (1): 35–44. doi:10.1080/15438600303733. PMC 2480497. PMID 12745669.
16. Stanway, G. & Hyypiä, T. (1999). "Parechoviruses". Journal of Virology. 73 (7): 5249–5254. doi:10.1128/JVI.73.7.5249-5254.1999. PMC 112579. PMID 10364270.
17. Pringle, C.R. (1996). "Virus Taxonomy 1996". Archives of Virology. 141 (11): 2251–2256. doi:10.1007/BF01718231. PMC 7086844. PMID 8992952.
18. Niklasson B, Kinnunen L, Hörnfeldt B, Hörling J, Benemar C, Hedlund KO, Matskova L, Hyypiä T, Winberg G (1999). "A new picornavirus isolated from bank voles (Clethrionomys glareolus)". Virology. 255 (1): 86–93. doi:10.1006/viro.1998.9557. PMID 10049824.
19. "Parechovirus.com". Parechovirus Research. Retrieved 2016-01-15.
20. "Viral meningitis in Kansas City-area babies probed". The Kansas City Star. The Associated Press. August 13, 2014.

External links

• 3D macromolecular structures of Parechoviruses from the EM Data Bank(EMDB)

• Picornaviridae
• Virus genera