title: West Nile virus surveillance, Brazil, 2008-2010.
abstract: BACKGROUND
  West Nile virus (WNV) is an emergent pathogen that is widely distributed in North and Central America. The recent introduction in South America has focused attention on the spread of WNV across Southern American countries. The transmission network involves mosquitoes, birds, horses and humans.
  
  
  METHODS
  The serological evaluation of sera from 678 equids and 478 birds was performed using a WNV-specific blocking ELISA, and only the positive results were confirmed by plaque reduction neutralisation tests (PRNTs). Molecular analysis was performed on sera from 992 healthy equids and on 63 macerates of brains from equids that died of encephalitis and had previously tested negative for other pathogens. We also tested swabs from 928 birds. The samples analysed were collected in different biomes of Brazil.
  
  
  RESULTS
  We identified WNV antibodies by ELISA in thirteen equids and five birds, and PRNT90 confirmed WNV positivity in four equid samples collected in 2009 in an area between the Amazon and the Pantanal. None of the ELISA positive bird samples were confirmed by PRNT90, and all samples tested by RT-PCR were negative.
  
  
  CONCLUSIONS
  WNV circulation is confirmed by this large scale survey even in the absence of detection of clinical cases.
authors.affiliation: BSL3 Laboratório de Virologia Clínica e Molecular Instituto de Ciências Biomédicas (ICB), Universidade de São Paulo (USP), 05508-900 São Paulo, Brasil.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Ometto
authors.forename: Edison Luiz
authors.initials: EL
authors.lastname: Durigon
authors.forename: Jansen
authors.initials: J
authors.lastname: de Araujo
authors.forename: Rosalie
authors.initials: R
authors.lastname: Aprelon
authors.forename: Daniel Moura
authors.initials: DM
authors.lastname: de Aguiar
authors.forename: Guacyara Tenorio
authors.initials: GT
authors.lastname: Cavalcante
authors.forename: Rosane Marini
authors.initials: RM
authors.lastname: Melo
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: Levi
authors.forename: Severino Mendes
authors.initials: SM
authors.lastname: de Azevedo Júnior
authors.forename: Maria Virgínia
authors.initials: MV
authors.lastname: Petry
authors.forename: Isaac Simão
authors.initials: IS
authors.lastname: Neto
authors.forename: Patrícia
authors.initials: P
authors.lastname: Serafini
authors.forename: Eliana
authors.initials: E
authors.lastname: Villalobos
authors.forename: Elenice Maria Sequetin
authors.initials: EM
authors.lastname: Cunha
authors.forename: Maria do Carmo Custódio S H
authors.initials: Mdo C
authors.lastname: Lara
authors.forename: Alessandra Ferreira Dales
authors.initials: AF
authors.lastname: Nava
authors.forename: Marcello Schiavo
authors.initials: MS
authors.lastname: Nardi
authors.forename: Renata
authors.initials: R
authors.lastname: Hurtado
authors.forename: Roberta
authors.initials: R
authors.lastname: Rodrigues
authors.forename: Angelo Luís
authors.initials: AL
authors.lastname: Sherer
authors.forename: Janete de Fátima Martins
authors.initials: Jde F
authors.lastname: Sherer
authors.forename: Marcelo Plaisant
authors.initials: MP
authors.lastname: Geraldi
authors.forename: Marina Maria Moraes
authors.initials: MM
authors.lastname: de Seixas
authors.forename: Cassio
authors.initials: C
authors.lastname: Peterka
authors.forename: Debora de Souza
authors.initials: Dde S
authors.lastname: Bandeira
authors.forename: Jennifer
authors.initials: J
authors.lastname: Pradel
authors.forename: Nathalie
authors.initials: N
authors.lastname: Vachiery
authors.forename: Marcelo Bahia
authors.initials: MB
authors.lastname: Labruna
authors.forename: Luiz Marcelo Aranha
authors.initials: LM
authors.lastname: de Camargo
authors.forename: Robert
authors.initials: R
authors.lastname: Lanciotti
authors.forename: Thierry
authors.initials: T
authors.lastname: Lefrançois
mesh_terms: D000818:Animals; D000835:Animals, Wild / Q000276:immunology; D000914:Antibodies, Viral / Q000097:blood*; D001717:Birds / Q000276:immunology; D001938:Brazil / Q000453:epidemiology; D009033:Culicidae / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006736:Horses / Q000276:immunology; D006801:Humans; D016036:Seroepidemiologic Studies; D014901:West Nile Fever / Q000175:diagnosis* / Q000453:epidemiology*; D014902:West Nile virus / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral
keywords: Brazil; Equids; Migratory birds; Molecular biology; Serology; West Nile virus