West nile virus causes: Difference between revisions
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The West Nile Virus may be classified in 5 phylogenetic lineages. Of these, only 1 and 2 have been identified as causative agents of disease in humans.<ref name=CDC>{{cite web | title = West Nile Virus | url = http://wwwnc.cdc.gov/eid/article/10/1/pdfs/02-0616.pdf }}</ref> | |||
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Lineage 1 can be further subdivided into 3 sublineages: iso- lates from the western hemisphere, Africa, the Middle East, and Europe constitute lineage 1a; Kunjin virus from Australasia repre- sents lineage 1b; and lineage 1c consists of viruses from India.16 The initial North American isolates (East Coast genotype) identi- fied in 1999 in New York City have been most closely related to a lineage 1a West Nile virus isolated from Israel in 1998.17 Since approximately 2002, the East Coast genotype has largely been displaced by a new genotype (WN02 genotype) encompassing several conserved amino acid substitutions that may have increased the efficiency and rapidity of viral transmission in North American mosquito vectors.7,18 | Lineage 1 can be further subdivided into 3 sublineages: iso- lates from the western hemisphere, Africa, the Middle East, and Europe constitute lineage 1a; Kunjin virus from Australasia repre- sents lineage 1b; and lineage 1c consists of viruses from India.16 The initial North American isolates (East Coast genotype) identi- fied in 1999 in New York City have been most closely related to a lineage 1a West Nile virus isolated from Israel in 1998.17 Since approximately 2002, the East Coast genotype has largely been displaced by a new genotype (WN02 genotype) encompassing several conserved amino acid substitutions that may have increased the efficiency and rapidity of viral transmission in North American mosquito vectors.7,18 | ||
Revision as of 14:36, 11 September 2014
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Taxonomy
Viruses; ssRNA viruses; ssRNA positive-strand viruses, no DNA stage; Flaviviridae; Flavivirus; Japanese encephalitis virus group[1]
Biology
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West Nile virus is a member of Japanese encephalitis serocomplex and belongs to the genus Flavivirus, family Flaviviridae. The virus has an icosahedral symmetry, with a smooth surface.[4] It is an enveloped virus with a nucleocapsid core built of RNA and capsid proteins. Its genome is contained in a single stranded mRNA virus of about 11000 bp.[5] It contains a single ORF, a 5' UTR, and a 3' region which is not translated. The ORF contains a single polyprotein, that after processed and translated produces 3 smaller types of structure proteins and 7 of non-strutural proteins.
- Structure proteins are responsible for the formation of the viral particle and include:
- Envelope proteins
- Membrane proteins
- C proteins
- Non-structure proteins are responsible for viral replication, evasion of the immune system and assembly of virions, and include:
- NS1
- NS2A
- NS2B
- NS3
- NS4A
- NS4B
- NS5
The West Nile Virus may be classified in 5 phylogenetic lineages. Of these, only 1 and 2 have been identified as causative agents of disease in humans.[6]
Structure
Tropism
Natural Reservoir
Natural reservoirs of the West Nile virus include:[7]
- Humans
- 65 different species of mosquitos
- 326 species of birds
References
- ↑ "West Nile Virus".
- ↑ "http://phil.cdc.gov/phil/details.asp". External link in
|title=(help) - ↑ "http://phil.cdc.gov/phil/details.asp". External link in
|title=(help) - ↑ Mukhopadhyay, S. (2003). "Structure of West Nile Virus". Science. 302 (5643): 248–248. doi:10.1126/science.1089316. ISSN 0036-8075.
- ↑ Campbell, Grant L; Marfin, Anthony A; Lanciotti, Robert S; Gubler, Duane J (2002). "West Nile virus". The Lancet Infectious Diseases. 2 (9): 519–529. doi:10.1016/S1473-3099(02)00368-7. ISSN 1473-3099.
- ↑ "West Nile Virus" (PDF).
- ↑ Petersen LR, Brault AC, Nasci RS (2013). "West Nile virus: review of the literature". JAMA. 310 (3): 308–15. doi:10.1001/jama.2013.8042. PMID 23860989.