title: Differential virulence and pathogenesis of West Nile viruses.
abstract: West Nile virus (WNV) is a neurotropic flavivirus that cycles between mosquitoes and birds but that can also infect humans, horses, and other vertebrate animals. In most humans, WNV infection remains subclinical. However, 20%-40% of those infected may develop WNV disease, with symptoms ranging from fever to meningoencephalitis. A large variety of WNV strains have been described worldwide. Based on their genetic differences, they have been classified into eight lineages; the pathogenic strains belong to lineages 1 and 2. Ten years ago, Beasley et al. (2002) found that dramatic differences exist in the virulence and neuroinvasion properties of lineage 1 and lineage 2 WNV strains. Further insights on how WNV interacts with its hosts have recently been gained; the virus acts either at the periphery or on the central nervous system (CNS), and these observed differences could help explain the differential virulence and neurovirulence of WNV strains. This review aims to summarize the current state of knowledge on factors that trigger WNV dissemination and CNS invasion as well as on the inflammatory response and CNS damage induced by WNV. Moreover, we will discuss how WNV strains differentially interact with the innate immune system and CNS cells, thus influencing WNV pathogenesis.
authors.affiliation: Université Paris Est Créteil (UPEC), UMR 1161 Virologie, Institut National de la Recherche Agronomique (INRA), Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (ANSES) , Ecole Nationale Vétérinaire d'Alfort (ENVA), 7 avenue du Général De Gaulle, Maisons-Alfort 94700, France. sylvie.lecollinet@anses.fr.
authors.forename: Emilie
authors.initials: E
authors.lastname: Donadieu
authors.forename: Céline
authors.initials: C
authors.lastname: Bahuon
authors.forename: Steeve
authors.initials: S
authors.lastname: Lowenski
authors.forename: Stéphan
authors.initials: S
authors.lastname: Zientara
authors.forename: Muriel
authors.initials: M
authors.lastname: Coulpier
authors.forename: Sylvie
authors.initials: S
authors.lastname: Lecollinet
mesh_terms: D000818:Animals; D002493:Central Nervous System Diseases / Q000276:immunology / Q000821:virology*; D006801:Humans; D014774:Virulence; D014901:West Nile Fever / Q000276:immunology / Q000821:virology*; D014902:West Nile virus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*