title: Genetic characterization of St. Louis encephalitis virus isolated from human in São Paulo, Brazil.
abstract: The molecular characterization of SPH253157, a new strain of St. Louis encephalitis virus (SLEV), isolated in 2004 from the first case of human infection recognized in the state of São Paulo, Brazil, is reported. The patient, presenting a febrile illness without neurological involvement, was hospitalized as a probable case of dengue fever. Genomic RNA was isolated from the supernatant of C6/36 cells infected with acute phase-serum specimen of the patient and the envelope gene was amplified by reverse-transcription-polymerase chain reaction. The complete nucleotide sequence of the envelope gene of this isolate was directly sequenced from the amplified products and compared with other Brazilian and American SLEV strains. Phylogenetic analyses were carried out under maximum likelihood criterion with outgroups both included and excluded. Outgroups comprised four flavivirus of the Japanese encephalitis group. Phylogeny also included Bayesian analysis. The results indicated that the new SLEV isolate belongs to lineage III, being closely related to an Argentinean strain recovered from Culex sp. in 1979. It is concluded that there are at least 3 lineages of SLEV in Brazil.
authors.affiliation: Serviço de Virologia, Instituto Adolfo Lutz, 01246-902 São Paulo, SP, Brazil. simoes.santos@uol.com.br
authors.forename: Cecília Luiza Simões dos
authors.initials: CL
authors.lastname: Santos
authors.forename: Maria Anice Mureb
authors.initials: MA
authors.lastname: Sallum
authors.forename: Heitor Moreira
authors.initials: HM
authors.lastname: Franco
authors.forename: Fabíola Maiumi
authors.initials: FM
authors.lastname: Oshiro
authors.forename: Iray Maria
authors.initials: IM
authors.lastname: Rocco
mesh_terms: D001938:Brazil; D004665:Encephalitis Virus, St. Louis / Q000235:genetics*; D016679:Genome, Viral; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000235:genetics*
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins