title: Regional-scale climate-variability synchrony of cholera epidemics in West Africa.
abstract: BACKGROUND
  The relationship between cholera and climate was explored in Africa, the continent with the most reported cases, by analyzing monthly 20-year cholera time series for five coastal adjoining West African countries: Côte d'Ivoire, Ghana, Togo, Benin and Nigeria.
  
  
  METHODS
  We used wavelet analyses and derived methods because these are useful mathematical tools to provide information on the evolution of the periodic component over time and allow quantification of non-stationary associations between time series.
  
  
  RESULTS
  The temporal variability of cholera incidence exhibits an interannual component, and a significant synchrony in cholera epidemics is highlighted at the end of the 1980's. This observed synchrony across countries, even if transient through time, is also coherent with both the local variability of rainfall and the global climate variability quantified by the Indian Oscillation Index.
  
  
  CONCLUSIONS
  Results of this study suggest that large and regional scale climate variability influence both the temporal dynamics and the spatial synchrony of cholera epidemics in human populations in the Gulf of Guinea, as has been described for two other tropical regions of the world, western South America and Bangladesh.
authors: Génétique et Evolution des Maladies Infectieuses, UMR CNRS/IRD 2724, 911 avenue Agropolis, BP 64501, 34394 Montpellier cedex 05, France. g.demagny@gmail.com
authors: Guillaume
authors: G
authors: Constantin de Magny
authors: Jean-François
authors: JF
authors: Guégan
authors: Michel
authors: M
authors: Petit
authors: Bernard
authors: B
authors: Cazelles
mesh_terms: D000354:Africa, Western / Q000453:epidemiology; D002771:Cholera / Q000453:epidemiology*; D002980:Climate; D004196:Disease Outbreaks; D004812:Epidemiologic Methods; D006801:Humans; D015994:Incidence; D011891:Rain; D012621:Seasons; D014887:Weather