title: Phylogenetic analysis of North American West Nile virus isolates, 2001-2004: evidence for the emergence of a dominant genotype.
abstract: The distribution of West Nile virus has expanded in the past 6 years to include the 48 contiguous United States and seven Canadian provinces, as well as Mexico, the Caribbean islands, and Colombia. The suggestion of the emergence of a dominant genetic variant has led to an intensive analysis of isolates made across North America. We have sequenced the pre-membrane and envelope genes of 74 isolates and the complete genomes of 25 isolates in order to determine if a dominant genotype has arisen and to better understand how the virus has evolved as its distribution has expanded. Phylogenetic analyses revealed the continued presence of genetic variants that group in a temporally and geographically dependent manner and provide evidence that a dominant variant has emerged across much of North America. The implications of these findings are discussed as they relate to transmission and spread of the virus in the Western Hemisphere.
authors.affiliation: Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, and Sealy Center for Vaccine Development, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77550-0609, USA.
authors.forename: C Todd
authors.initials: CT
authors.lastname: Davis
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Ebel
authors.forename: Robert S
authors.initials: RS
authors.lastname: Lanciotti
authors.forename: Aaron C
authors.initials: AC
authors.lastname: Brault
authors.forename: Hilda
authors.initials: H
authors.lastname: Guzman
authors.forename: Marina
authors.initials: M
authors.lastname: Siirin
authors.forename: Amy
authors.initials: A
authors.lastname: Lambert
authors.forename: Ray E
authors.initials: RE
authors.lastname: Parsons
authors.forename: David W C
authors.initials: DW
authors.lastname: Beasley
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Novak
authors.forename: Darwin
authors.initials: D
authors.lastname: Elizondo-Quiroga
authors.forename: Emily N
authors.initials: EN
authors.lastname: Green
authors.forename: David S
authors.initials: DS
authors.lastname: Young
authors.forename: Lillian M
authors.initials: LM
authors.lastname: Stark
authors.forename: Michael A
authors.initials: MA
authors.lastname: Drebot
authors.forename: Harvey
authors.initials: H
authors.lastname: Artsob
authors.forename: Robert B
authors.initials: RB
authors.lastname: Tesh
authors.forename: Laura D
authors.initials: LD
authors.lastname: Kramer
authors.forename: Alan D T
authors.initials: AD
authors.lastname: Barrett
mesh_terms: D005814:Genes, Viral; D014644:Genetic Variation; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009656:North America; D013045:Species Specificity; D014759:Viral Envelope Proteins / Q000235:genetics; D014902:West Nile virus / Q000235:genetics*
chemical_list: D014759:Viral Envelope Proteins