title: Genetic determinants of differential oral infection phenotypes of West Nile and St. Louis encephalitis viruses in Culex spp. mosquitoes.
abstract: St. Louis encephalitis virus (SLEV) has shown greater susceptibility to oral infectivity than West Nile virus (WNV) in Culex mosquitoes. To identify the viral genetic elements that modulate these disparate phenotypes, structural chimeras (WNV-pre-membrane [prM] and envelope [E] proteins [prME]/SLEV.IC (infectious clone) and SLEV-prME/WNV.IC) were constructed in which two of the structural proteins, the prM and E, were interchanged between viruses. Oral dose-response assessment with the chimeric/parental WNV and SLEV was performed to characterize the infection phenotypes in Culex mosquitoes by artificial blood meals. The median infectious dose required to infect 50% of Cx. quinquefasciatus with WNV was indistinguishable from that of the SLEV-prME/WNV.IC chimeric virus. Similarly, SLEV and WNV-prME/SLEV.IC virus exhibited an indistinguishable oral dose-response relationship in Cx. quinquefasciatus. Infection rates for WNV.IC and SLEV-prME/WNV.IC were significantly lower than SLEV.IC and WNV-prME/SLEV.IC infection rates. These results indicated that WNV and SLEV oral infectivities are not mediated by genetic differences within the prM and E proteins.
authors.affiliation: Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California.
authors.forename: Payal D
authors.initials: PD
authors.lastname: Maharaj
authors.affiliation: Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California.
authors.forename: Bethany G
authors.initials: BG
authors.lastname: Bolling
authors.affiliation: Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California.
authors.forename: Michael
authors.initials: M
authors.lastname: Anishchenko
authors.affiliation: Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California.
authors.forename: William K
authors.initials: WK
authors.lastname: Reisen
authors.affiliation: Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado; Center for Vectorborne Diseases and Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California abrault@cdc.gov.
authors.forename: Aaron C
authors.initials: AC
authors.lastname: Brault
mesh_terms: D000818:Animals; D003465:Culex / Q000821:virology*; D009033:Culicidae / Q000821:virology*; D004665:Encephalitis Virus, St. Louis / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D010641:Phenotype; D014764:Viral Proteins / Q000235:genetics* / Q000302:isolation & purification; D014902:West Nile virus / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D014764:Viral Proteins