Copyright ©2012 Baishideng. All rights reserved.
World J Virol. Apr 12, 2012; 1(2): 51-70
Published online Apr 12, 2012. doi: 10.5501/wjv.v1.i2.51
West Nile virus: A re-emerging pathogen revisited
Miguel A Martín-Acebes, Juan-Carlos Saiz
Miguel A Martín-Acebes, Juan-Carlos Saiz, Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain
Author contributions: Martín-Acebes MA and Saiz JC equally contributed to this paper.
Supported by Grants No. RTA2011-00036, SAF2008-04232 and FAU2008-00006 from the Spanish Ministerio de Ciencia e Innovación; and the European Community’s Seventh Framework Programme (No. FP/2007-2013) under Grant Agreement 28394
Correspondence to: Juan-Carlos Saiz, Research Leader, Director of the Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28040 Madrid, Spain.
Telephone: +34-91-3471497 Fax: +34-91-3478771
Received: August 19, 2011
Revised: February 16, 2012
Accepted: March 5, 2012
Published online: April 12, 2012

West Nile virus (WNV), a flavivirus of the Flaviviridae family, is maintained in nature in an enzootic transmission cycle between avian hosts and ornithophilic mosquito vectors, although the virus occasionally infects other vertebrates. WNV causes sporadic disease outbreaks in horses and humans, which may result in febrile illness, meningitis, encephalitis and flaccid paralysis. Until recently, its medical and veterinary health concern was relatively low; however, the number, frequency and severity of outbreaks with neurological consequences in humans and horses have lately increased in Europe and the Mediterranean basin. Since its introduction in the Americas, the virus spread across the continent with worrisome consequences in bird mortality and a considerable number of outbreaks among humans and horses, which have resulted in the largest epidemics of neuroinvasive WNV disease ever documented. Surprisingly, its incidence in human and animal health is very different in Central and South America, and the reasons for it are not yet understood. Even though great advances have been obtained lately regarding WNV infection, and although efficient equine vaccines are available, no specific treatments or vaccines for human use are on the market. This review updates the most recent investigations in different aspects of WNV life cycle: molecular virology, transmission dynamics, host range, clinical presentations, epidemiology, ecology, diagnosis, control, and prevention, and highlights some aspects that certainly require further research.

Keywords: West Nile virus, Emerging pathogen, Molecular biology, Diagnosis, Pathology, Epidemiology, Vaccines, Antivirals