title: Molecular epidemiology of Saint Louis encephalitis virus in the Brazilian Amazon: genetic divergence and dispersal.
abstract: Saint Louis encephalitis virus (SLEV), a member of the genus Flavivirus (family Flaviviridae), is an encephalitogenic arbovirus broadly distributed in the Americas. Phylogenetic analysis based on the full-length E gene sequences obtained for 30 Brazilian SLEV strains was performed using different methods including Bayesian and relaxed molecular clock approaches. A new genetic lineage was suggested, hereafter named genotype VIII, which co-circulates with the previously described genotype V in the Brazilian Amazon region. Genotypes II and III were restricted to São Paulo state (South-east Atlantic rainforest ecosystem). The analysis also suggested the emergence of an SLEV common ancestor between 1875 and 1973 (mean of 107 years ago), giving rise to two major genetic groups: genotype II, more prevalent in the North America, and a second group comprising the other genotypes (I and III-VIII), broadly dispersed throughout the Americas, suggesting that SLEV initially emerged in South America and spread to North America. In conclusion, the current study demonstrates the high genetic variability of SLEV and its geographical dispersion in Brazil and other New World countries.
authors.affiliation: Seção de Arbovirologia e Febres Hemorrágicas, Instituto Evandro Chagas, Secretaria de Vigilância em Saúde, Ministério da Saúde, Ananindeua, Brazil.
authors.forename: Sueli G
authors.initials: SG
authors.lastname: Rodrigues
authors.forename: Márcio R T
authors.initials: MR
authors.lastname: Nunes
authors.forename: Samir M M
authors.initials: SM
authors.lastname: Casseb
authors.forename: Assis S C
authors.initials: AS
authors.lastname: Prazeres
authors.forename: Daniela S G
authors.initials: DS
authors.lastname: Rodrigues
authors.forename: Mayra O
authors.initials: MO
authors.lastname: Silva
authors.forename: Ana C R
authors.initials: AC
authors.lastname: Cruz
authors.forename: José C
authors.initials: JC
authors.lastname: Tavares-Neto
authors.forename: Pedro F C
authors.initials: PF
authors.lastname: Vasconcelos
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D016000:Cluster Analysis; D004665:Encephalitis Virus, St. Louis / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D004674:Encephalitis, St. Louis / Q000453:epidemiology* / Q000662:veterinary* / Q000821:virology; D019143:Evolution, Molecular; D005838:Genotype; D007313:Insecta / Q000821:virology; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000235:genetics
chemical_list: D014764:Viral Proteins