Phylogenetic analysis of North American West Nile virus isolates, 2001-2004: evidence for the emergence of a dominant genotype.
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.
Davis
C Todd
CT
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.
Ebel
Gregory D
GD
Lanciotti
Robert S
RS
Brault
Aaron C
AC
Guzman
Hilda
H
Siirin
Marina
M
Lambert
Amy
A
Parsons
Ray E
RE
Beasley
David W C
DW
Novak
Robert J
RJ
Elizondo-Quiroga
Darwin
D
Green
Emily N
EN
Young
David S
DS
Stark
Lillian M
LM
Drebot
Michael A
MA
Artsob
Harvey
H
Tesh
Robert B
RB
Kramer
Laura D
LD
Barrett
Alan D T
AD
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*
D014759:Viral Envelope Proteins