title: Neutralising antibodies for West Nile virus in horses from Brazilian Pantanal.
abstract: Despite evidence of West Nile virus (WNV) activity in Colombia, Venezuela and Argentina, this virus has not been reported in most South American countries. In February 2009, we commenced an investigation for WNV in mosquitoes, horses and caimans from the Pantanal, Central-West Brazil. The sera of 168 horses and 30 caimans were initially tested using a flaviviruses-specific epitope-blocking enzyme-linked immunosorbent assay (blocking ELISA) for the detection of flavivirus-reactive antibodies. The seropositive samples were further tested using a plaque-reduction neutralisation test (PRNT90) for WNV and its most closely-related flaviviruses that circulate in Brazil to confirm the detection of specific virus-neutralising antibodies. Of the 93 (55.4%) blocking ELISA-seropositive horse serum samples, five (3%) were seropositive for WNV, nine (5.4%) were seropositive for St. Louis encephalitis virus, 18 (10.7%) were seropositive for Ilheus virus, three (1.8%) were seropositive for Cacipacore virus and none were seropositive for Rocio virus using PRNT90, with a criteria of ≥ four-fold antibody titre difference. All caimans were negative for flaviviruses-specific antibodies using the blocking ELISA. No virus genome was detected from caiman blood or mosquito samples. The present study is the first report of confirmed serological evidence of WNV activity in Brazil.
authors: Laboratório de Flavivírus, Instituto Oswaldo Cruz-Fiocruz, Ministério da Saúde, Avenida Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brasil. pauvolid@ioc.fiocruz.br
authors: Alex
authors: A
authors: Pauvolid-Corrêa
authors: Maria Alejandra
authors: MA
authors: Morales
authors: Silvana
authors: S
authors: Levis
authors: Luis Tadeu Moraes
authors: LT
authors: Figueiredo
authors: Dinair
authors: D
authors: Couto-Lima
authors: Zilca
authors: Z
authors: Campos
authors: Marcia Furlan
authors: MF
authors: Nogueira
authors: Edson Elias
authors: EE
authors: da Silva
authors: Rita Maria Ribeiro
authors: RM
authors: Nogueira
authors: Hermann Gonçalves
authors: HG
authors: Schatzmayr
mesh_terms: D000489:Alligators and Crocodiles / Q000276:immunology / Q000821:virology*; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood* / Q000276:immunology; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D001938:Brazil; D009033:Culicidae / Q000276:immunology / Q000821:virology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006734:Horse Diseases / Q000175:diagnosis / Q000276:immunology / Q000821:virology*; D006736:Horses / Q000276:immunology / Q000821:virology*; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014901:West Nile Fever / Q000175:diagnosis / Q000662:veterinary*; D014902:West Nile virus / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral