West nile virus

(Redirected from West Nile Virus)
Jump to: navigation, search

West nile virus infection Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating West nile virus infection from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

Chest X Ray

CT

MRI

Echocardiography or Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

West nile virus On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of West nile virus

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on West nile virus

CDC on West nile virus

West nile virus in the news

Blogs on West nile virus

Directions to Hospitals Treating West nile virus infection

Risk calculators and risk factors for West nile virus

This page is about microbiologic aspects of the organism(s).  For clinical aspects of the disease, see West nile virus infection.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

WNV is an enveloped positive-sense ssRNA virus of 11000 base pairs (bp) that is considered a member of the Japanese encephalitis serocomplex. It belongs to the genus Flavivirus and family Flaviviridae. Its RNA encodes structural and non-structural proteins. Although 7 lineages of WNV have been described, only lineage 1 and 2 are clinically significant. The viral natural reservoir includes many species, such as humans, horses, dogs, and cats; but the main natural reservoir is birds.

Taxonomy

Viruses; ssRNA viruses; ssRNA positive-strand viruses, no DNA stage; Flaviviridae; Flavivirus; Japanese encephalitis virus group[1]

Biology

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 [2]

WNV is a member of Japanese encephalitis serocomplex and belongs to the genus Flavivirus, family Flaviviridae. Other species of the this serocomplex include the St Louis encephalitis virus and the Japanese encephalitis virus.[3]

The WNV 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 RNA of about 11000 bp.[5] It contains a single open reading frame (ORF), a 5' untranslated region (UTR), and another 3' region which is also not translated. The ORF contains a single polyprotein that produces 3 smaller types of structure proteins and 7 of non-structural proteins following processing and translation.

  • Structural proteins are responsible for the formation of the viral particle and include:
  • Envelope proteins
  • Membrane proteins
  • C proteins
  • Non-structural proteins are responsible for viral replication, evasion of the immune system, and assembly of virions. They include:
  • NS1
  • NS2A
  • NS2B
  • NS3
  • NS4A
  • NS4B
  • NS5

The WNV may be classified in 7 phylogenetic lineages. Of these, only 1 and 2 have been identified as causative agents of disease in humans and are considered clinically significant.[6][7][8][9][10][11][12][13]

  • Lineage 1: Widespread, isolates from Europe, America, Middle East, India, Africa, and Australia
  • Lingeage 2: Southern Africa, Madagascar, and Europe

Natural reservoir

Although WNV can infect humans and numerous animals, birds are its main natural reservoir.[3][5]

Gallery

References

  1. "West Nile Virus". 
  2. "http://phil.cdc.gov/phil/details.asp".  External link in |title= (help)
  3. 3.0 3.1 Petersen LR, Brault AC, Nasci RS (2013). "West Nile virus: review of the literature.". JAMA. 310 (3): 308–15. PMID 23860989. doi:10.1001/jama.2013.8042. 
  4. Mukhopadhyay, S. (2003). "Structure of West Nile Virus". Science. 302 (5643): 248–248. ISSN 0036-8075. doi:10.1126/science.1089316. 
  5. 5.0 5.1 Campbell, Grant L; Marfin, Anthony A; Lanciotti, Robert S; Gubler, Duane J (2002). "West Nile virus". The Lancet Infectious Diseases. 2 (9): 519–529. ISSN 1473-3099. doi:10.1016/S1473-3099(02)00368-7. 
  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. PMC 3023431Freely accessible. PMID 12890319. doi:10.3201/eid0907.030085. 
  8. Bakonyi T, Ivanics E, Erdélyi K, Ursu K, Ferenczi E, Weissenböck H; et al. (2006). "Lineage 1 and 2 strains of encephalitic West Nile virus, central Europe.". Emerg Infect Dis. 12 (4): 618–23. PMC 3294705Freely accessible. PMID 16704810. doi:10.3201/eid1204.051379. 
  9. Charrel RN, Brault AC, Gallian P, Lemasson JJ, Murgue B, Murri S; et al. (2003). "Evolutionary relationship between Old World West Nile virus strains. Evidence for viral gene flow between Africa, the Middle East, and Europe.". Virology. 315 (2): 381–8. PMID 14585341. 
  10. Lanciotti RS, Ebel GD, Deubel V, Kerst AJ, Murri S, Meyer R; et al. (2002). "Complete genome sequences and phylogenetic analysis of West Nile virus strains isolated from the United States, Europe, and the Middle East.". Virology. 298 (1): 96–105. PMID 12093177. 
  11. Papa A, Xanthopoulou K, Gewehr S, Mourelatos S (2011). "Detection of West Nile virus lineage 2 in mosquitoes during a human outbreak in Greece.". Clin Microbiol Infect. 17 (8): 1176–80. PMID 21781205. doi:10.1111/j.1469-0691.2010.03438.x. 
  12. Savini G, Capelli G, Monaco F, Polci A, Russo F, Di Gennaro A; et al. (2012). "Evidence of West Nile virus lineage 2 circulation in Northern Italy.". Vet Microbiol. 158 (3-4): 267–73. PMID 22406344. doi:10.1016/j.vetmic.2012.02.018. 
  13. Valiakos G, Touloudi A, Iacovakis C, Athanasiou L, Birtsas P, Spyrou V; et al. (2011). "Molecular detection and phylogenetic analysis of West Nile virus lineage 2 in sedentary wild birds (Eurasian magpie), Greece, 2010.". Euro Surveill. 16 (18). PMID 21586266. 
  14. 14.0 14.1 14.2 "Public Health Image Library (PHIL)". 

Linked-in.jpg