title: Expansion of the dengue transmission area in Brazil: the role of climate and cities.
abstract: OBJECTIVE
  To examine the spatial and temporal patterns of the recent expansion of dengue transmission area in Brazil (2001-2012) with the aim to identify pathways and constraints to dengue diffusion.
  
  
  METHODS
  Synthetic indicators were calculated to characterise timing (year of first dengue outbreak), permanence (number of years with dengue outbreaks) and intensity (outbreak occurrence). The indicators were used to map dengue diffusion and compare cities within different climatic zones, with varying population densities.
  
  
  RESULTS
  Currently, a large portion of the country comprises a dengue transmission area, but cities situated in the mesothermal zone, in the south, and remote areas, in the north, are relatively exempt. Diffusion waves are spread from metropolitan areas towards medium and small cities generating outbreaks in their influence region. However, long-term permanence of transmission depends on the existence of a favourable climate, abundant population and connectivity.
  
  
  CONCLUSIONS
  Large and warm cities sustain and spread dengue viruses, for which specific dengue control measures must be developed. The concentration of outbreaks along climate transition fringes indicates a boundary between two transmission regimes and raises awareness to the effects of ongoing climatic and socio-economic changes.
authors.affiliation: Instituto de Comunicação e Informação Científica e Tecnológica, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: Christovam
authors.initials: C
authors.lastname: Barcellos
authors.forename: Rachel
authors.initials: R
authors.lastname: Lowe
mesh_terms: D001938:Brazil / Q000453:epidemiology; D002947:Cities; D002980:Climate; D003715:Dengue / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D003716:Dengue Virus; D004196:Disease Outbreaks; D006801:Humans
keywords: climate change; dengue epidemics; disease diffusion; urban health