title: Origins of dengue type 2 viruses associated with increased pathogenicity in the Americas.
abstract: The recent emergence and spread of dengue hemorrhagic fever in the Americas have been a major source of concern. Efforts to control this disease are dependent on understanding the pathogenicity of dengue viruses and their transmission dynamics. Pathogenicity studies have been hampered by the lack of in vitro or in vivo models of severe dengue disease. Alternatively, molecular epidemiologic studies which associate certain dengue virus genetic types with severe dengue outbreaks may point to strains with increased pathogenicity. The comparison of nucleotide sequences (240 bp) from the E/NS1 gene region of the dengue virus genome has been shown to reflect evolutionary relationships and geographic origins of dengue virus strains. This approach was used to demonstrate an association between the introduction of two distinct genotypes of dengue type 2 virus and the appearance of dengue hemorrhagic fever in the Americas. Phylogenetic analyses suggest that these genotypes originated in Southeast Asia and that they displaced the native, American genotype in at least four countries. Vaccination and other control efforts should therefore be directed at decreasing the transmission of these "virulent" genotypes.
authors.affiliation: Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: R
authors.initials: R
authors.lastname: Rico-Hesse
authors.forename: L M
authors.initials: LM
authors.lastname: Harrison
authors.forename: R A
authors.initials: RA
authors.lastname: Salas
authors.forename: D
authors.initials: D
authors.lastname: Tovar
authors.forename: A
authors.initials: A
authors.lastname: Nisalak
authors.forename: C
authors.initials: C
authors.lastname: Ramos
authors.forename: J
authors.initials: J
authors.lastname: Boshell
authors.forename: M T
authors.initials: MT
authors.lastname: de Mesa
authors.forename: R M
authors.initials: RM
authors.lastname: Nogueira
authors.forename: A T
authors.initials: AT
authors.lastname: da Rosa
mesh_terms: D001483:Base Sequence; D001938:Brazil; D003105:Colombia; D004279:DNA, Viral; D003715:Dengue / Q000821:virology*; D003716:Dengue Virus / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity*; D005838:Genotype; D006801:Humans; D008800:Mexico; D008969:Molecular Sequence Data; D010802:Phylogeny; D014687:Venezuela; D014759:Viral Envelope Proteins / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; C051821:E-glycoprotein, Dengue virus type 2; C079340:NS1 protein, Dengue virus type 2; D014759:Viral Envelope Proteins; D017361:Viral Nonstructural Proteins