title: Potential effect of population and climate changes on global distribution of dengue fever: an empirical model.
abstract: BACKGROUND
  Existing theoretical models of the potential effects of climate change on vector-borne diseases do not account for social factors such as population increase, or interactions between climate variables. Our aim was to investigate the potential effects of global climate change on human health, and in particular, on the transmission of vector-borne diseases.
  
  
  METHODS
  We modelled the reported global distribution of dengue fever on the basis of vapour pressure, which is a measure of humidity. We assessed changes in the geographical limits of dengue fever transmission, and in the number of people at risk of dengue by incorporating future climate change and human population projections into our model.
  
  
  RESULTS
  We showed that the current geographical limits of dengue fever transmission can be modelled with 89% accuracy on the basis of long-term average vapour pressure. In 1990, almost 30% of the world population, 1.5 billion people, lived in regions where the estimated risk of dengue transmission was greater than 50%. With population and climate change projections for 2085, we estimate that about 5-6 billion people (50-60% of the projected global population) would be at risk of dengue transmission, compared with 3.5 billion people, or 35% of the population, if climate change did not happen.
  
  
  CONCLUSIONS
  We conclude that climate change is likely to increase the area of land with a climate suitable for dengue fever transmission, and that if no other contributing factors were to change, a large proportion of the human population would then be put at risk.
authors.affiliation: Department of Public Health, Wellington School of Medicine and Health Sciences, PO box 7343, Mein Street, Wellington, New Zealand. shales@wnmeds.ac.nz
authors.forename: Simon
authors.initials: S
authors.lastname: Hales
authors.forename: Neil
authors.initials: N
authors.lastname: de Wet
authors.forename: John
authors.initials: J
authors.lastname: Maindonald
authors.forename: Alistair
authors.initials: A
authors.lastname: Woodward
mesh_terms: D000330:Aedes / Q000254:growth & development / Q000821:virology; D000818:Animals; D003715:Dengue / Q000635:transmission*; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D005544:Forecasting; D017752:Greenhouse Effect; D006801:Humans; D006813:Humidity; D016015:Logistic Models; D011157:Population Dynamics; D012306:Risk; D019371:Topography, Medical