title: Epidemiological history and phylogeography of West Nile virus lineage 2.
abstract: West Nile virus (WNV) was first isolated in Uganda. In Europe WNV was sporadically detected until 1996, since then the virus has been regularly isolated from birds and mosquitoes and caused several outbreaks in horses and humans. Phylogenetic analysis showed two main different WNV lineages. The lineage 1 is widespread and segregates into different subclades (1a-c). WNV-1a includes numerous strains from Africa, America, and Eurasia. The spatio-temporal history of WNV-1a in Europe was recently described, identifying two main routes of dispersion, one in Eastern and the second in Western Europe. The West Nile lineage 2 (WNV-2) is mainly present in sub-Saharan Africa but has been recently emerged in Eastern and Western European countries. In this study we reconstruct the phylogeny of WNV-2 on a spatio-temporal scale in order to estimate the time of origin and patterns of geographical dispersal of the different isolates, particularly in Europe. Phylogeography findings obtained from E and NS5 gene analyses suggest that there were at least two separate introductions of WNV-2 from the African continent dated back approximately to the year 1999 (Central Europe) and 2000 (Russia), respectively. The epidemiological implications and clinical consequences of lineage 1 and 2 cocirculation deserve further investigations.
authors.affiliation: Department of Infectious, National Institute of Health, Rome, Italy. massimo.ciccozzi@iss.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Ciccozzi
authors.forename: Simone
authors.initials: S
authors.lastname: Peletto
authors.forename: Eleonora
authors.initials: E
authors.lastname: Cella
authors.forename: Marta
authors.initials: M
authors.lastname: Giovanetti
authors.forename: Alessia
authors.initials: A
authors.lastname: Lai
authors.forename: Elena
authors.initials: E
authors.lastname: Gabanelli
authors.forename: Pier Luigi
authors.initials: PL
authors.lastname: Acutis
authors.forename: Paola
authors.initials: P
authors.lastname: Modesto
authors.forename: Giovanni
authors.initials: G
authors.lastname: Rezza
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Platonov
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lo Presti
authors.forename: Gianguglielmo
authors.initials: G
authors.lastname: Zehender
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005060:Europe / Q000453:epidemiology; D019143:Evolution, Molecular; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D010802:Phylogeny; D058974:Phylogeography; D014759:Viral Envelope Proteins / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics; D014901:West Nile Fever / Q000453:epidemiology* / Q000266:history; D014902:West Nile virus / Q000145:classification* / Q000235:genetics*
chemical_list: C096041:NS5 protein, flavivirus; D014759:Viral Envelope Proteins; D017361:Viral Nonstructural Proteins