title: Serological evidence of West Nile virus infection in the horse population of northern Serbia.
abstract: BACKGROUND
  This study was conducted to evaluate the seroprevalence of West Nile virus (WNV) in the horse population of northern Serbia. Furthermore, it aimed to provide insight and an updated overview on the circulation of this re-emerging pathogen in this part of southeastern Europe. At the time of manuscript preparation, no clinical cases of WNV infection in horses were reported in this area.
  
  
  METHODS
  Between 2007 and 2011, a total of 252 equine serum samples were collected from seven different locations in northern Serbia. The presence of WNV-reactive IgG antibodies was examined by using commercial and in-house ELISAs. Selected ELISA-positive samples were re-tested by a WNV lineage 2 plaque reduction neutralization test 90% (PRNT-90).
  
  
  RESULTS
  In 28.6% of the 252 tested equine serum samples antibodies against WNV were detected. The results obtained with the in-house ELISA corresponded to the outcome of the commercial kit in 90% of the samples. All selected WNV antibody ELISA-positive samples were confirmed by PRNT-90 with neutralizing antibody titers of 1:23 to > 1:512.
  
  
  CONCLUSIONS
  This study confirms the circulation of WNV in northern Serbia. No striking regional differences in seroprevalences were identified suggesting WNV circulation also in other parts of Serbia. Distances between wetlands or forests and stud farms do not appear to have an influence on WNV seroprevalence.
authors.affiliation: University of Veterinary Medicine Vienna, Vienna, Austria. strmbg@gmail.com.
authors.forename: Strahinja
authors.initials: S
authors.lastname: Medić
authors.forename: Rene
authors.initials: R
authors.lastname: van den Hoven
authors.forename: Tamaš
authors.initials: T
authors.lastname: Petrović
authors.forename: Diana
authors.initials: D
authors.lastname: Lupulović
authors.forename: Norbert
authors.initials: N
authors.lastname: Nowotny
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D058345:Asymptomatic Infections; D004797:Enzyme-Linked Immunosorbent Assay; D006734:Horse Diseases / Q000821:virology; D006736:Horses / Q000821:virology*; D009500:Neutralization Tests; D055771:Serbia; D016036:Seroepidemiologic Studies; D011795:Surveys and Questionnaires; D014901:West Nile Fever / Q000662:veterinary / Q000821:virology; D014902:West Nile virus / Q000302:isolation & purification*
chemical_list: D000914:Antibodies, Viral