title: Dynamic behavior of sylvatic yellow fever in Brazil (1954-2008).
abstract: BACKGROUND
  Sylvatic yellow fever (SYF) is enzootic in Brazil, causing periodic outbreaks in humans living near forest borders or in rural areas. In this study, the cycling patterns of this arbovirosis were analyzed.
  
  
  METHODS
  Spectral Fourier analysis was used to capture the periodicity patterns of SYF in time series.
  
  
  RESULTS
  SYF outbreaks have not increased in frequency, only in the number of cases. There are two dominant cycles in SYF outbreaks, a seven year cycle for the central-western region and a 14 year cycle for the northern region. Most of the variance was concentrated in the central-western region and dominated the entire endemic region.
  
  
  CONCLUSIONS
  The seven year cycle is predominant in the endemic region of the disease due the greater contribution of variance in the central-western region; however, it was possible identify a 14 cycle that governs SYF outbreaks in the northern region. No periodicities were identified for the remaining geographical regions.
authors.affiliation: Setor de Epidemiologia de Doenças Infecto-Contagiosas, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ. portela@micro.ufrj.br
authors.forename: Fernando Portela
authors.initials: FP
authors.lastname: Câmara
authors.forename: Ana Luisa Bessa Bacellar
authors.initials: AL
authors.lastname: Gomes
authors.forename: Luiz Max Fagundes de
authors.initials: LM
authors.lastname: Carvalho
authors.forename: Luiz Gustavo Veloso
authors.initials: LG
authors.lastname: Castello
mesh_terms: D001938:Brazil / Q000453:epidemiology; D004196:Disease Outbreaks; D006801:Humans; D010507:Periodicity; D015004:Yellow Fever / Q000453:epidemiology*