title: Genotype-specific variation in West Nile virus dispersal in California.
abstract: West Nile virus (WNV) is an arbovirus that was first reported in North America in New York in 1999 and, by 2003, had spread more than 4000 km to California. However, variation in viral genetics associated with spread is not well understood. Herein, we report sequences for more than 100 WNV isolates made from mosquito pools that were collected from 2003 to 2011 as part of routine surveillance by the California Mosquito-borne Virus Surveillance System. We performed phylogeographic analyses and demonstrated that 5 independent introductions of WNV (1 WN02 genotype strain and 4 SW03 genotype strains) occurred in California. The SW03 genotype of WNV was constrained to the southwestern U.S. and had a more rapid rate of spread. In addition, geographic constraint of WNV strains within a single region for up to 6 years suggest viral maintenance has been driven by resident, rather than migratory, birds and overwintering in mosquitoes.
authors.affiliation: Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
authors.forename: Nisha K
authors.initials: NK
authors.lastname: Duggal
authors.affiliation: Center for Vectorborne Diseases, University of California, Davis, CA, USA.
authors.forename: William K
authors.initials: WK
authors.lastname: Reisen
authors.affiliation: Center for Vectorborne Diseases, University of California, Davis, CA, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA.
authors.forename: Ruchi M
authors.initials: RM
authors.lastname: Newman
authors.affiliation: Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Ebel
authors.affiliation: Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA. Electronic address: abrault@cdc.gov.
authors.forename: Aaron C
authors.initials: AC
authors.lastname: Brault
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D001717:Birds / Q000821:virology; D002140:California / Q000453:epidemiology; D003465:Culex / Q000821:virology*; D062665:Epidemiological Monitoring; D016679:Genome, Viral; D005838:Genotype; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D019476:Insect Proteins / Q000235:genetics*; D007303:Insect Vectors / Q000821:virology*; D016366:Open Reading Frames; D010641:Phenotype; D010802:Phylogeny; D058974:Phylogeography; D012621:Seasons; D014901:West Nile Fever / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D014902:West Nile virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D019476:Insect Proteins
keywords: Arbovirus; Evolution; Phylogenetics; West Nile virus