West nile virus causes: Difference between revisions

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* 65 different species of mosquitos
* 65 different species of mosquitos
* 326 [[species]] of birds
* 326 [[species]] of birds
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*West Nile virus was first identified in 1937 in Uganda in eastern Africa. It was first discovered in the United States in the summer of 1999 in New York. Since then, the virus has spread throughout the United States.
*The West Nile virus is a type of virus known as a [[flavivirus]]. Researchers believe West Nile virus is spread when a mosquito bites an infected bird and then bites a person.
*Mosquitos carry the highest amounts of virus in the early fall, which is why the rate of the disease increases in late August to early September. The risk of disease decreases as the weather becomes colder and mosquitos die off.
*Although many people are bitten by mosquitos that carry West Nile virus, most do not know they've been exposed. Few people develop severe disease or even notice any symptoms at all.
*West Nile virus may also be spread through [[blood transfusions]] and [[organ transplants]]. It is possible for an infected mother to spread the [[virus]] to her child through [[breast milk]].
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==References==
==References==
{{Reflist|2}}
{{Reflist|2}}

Revision as of 14:47, 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

Digitally-colorized transmission electron micrograph (TEM) of the West Nile virus (WNV). Image provided by the CDC Centers for Disease Control and Prevention [2]
Presence of West Nile virus virions, in an isolate that was grown in a cell culture. Image provided by the CDC Centers for Disease Control and Prevention [3]

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] Lineage 1 may be subclassified into 3 other lineages, which predominate in certain parts of the world:[7]

  • Lineage 1a - western hemisphere, Africa, the Middle East, and Europe
  • Lineage 1b - Kunjin virus from Australasia
  • Lineage 1c - virus in India

Tropism

Natural Reservoir

Natural reservoirs of the West Nile virus include:[8]

  • Humans
  • 65 different species of mosquitos
  • 326 species of birds

References

  1. ↑ "West Nile Virus".
  2. ↑ "http://phil.cdc.gov/phil/details.asp". External link in |title= (help)
  3. ↑ "http://phil.cdc.gov/phil/details.asp". External link in |title= (help)
  4. ↑ Mukhopadhyay, S. (2003). "Structure of West Nile Virus". Science. 302 (5643): 248–248. doi:10.1126/science.1089316. ISSN 0036-8075.
  5. ↑ 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.
  6. ↑ "West Nile Virus" (PDF).
  7. ↑ Miller DL, Mauel MJ, Baldwin C, Burtle G, Ingram D, Hines ME; et al. (2003). "West Nile virus in farmed alligators". Emerg Infect Dis. 9 (7): 794–9. doi:10.3201/eid0907.030085. PMC 3023431. PMID 12890319.
  8. ↑ 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.
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