[Impact of global climate changes on arboviruses transmitted to humans by mosquitoes and ticks]

Global warming [+0.5-0.6 degree C during the second half of the 20th century] seems a reality although climatologists did not reach a common agreement on its actual origin, and this phenomenon may still increase along the 21st century [+1.5 to 6 degrees C]. Epidemiologists are anxious at the eventual effects of the resulting climate change on the evolution of arbovirus infections transmitted to human beings by hematophagous vectors such as mosquitoes and ticks. Analysis of the literature devoted to this problem did not lead to precise conclusions and the mathematical models used seems insufficient for they take into account mainly the climatic factors and not enough the human ones. Examples of dengue, european tick-borne encephalitis and other arbovirus infections are discussed. Peculiar attention is devoted to the eventual effects of climatic changes on the hibernation process in some small mammals and the timing of bird's migrations, involved in enzootic cycles of arboviruses. It is likely that arbovirus diseases may locally extend, both in latitude and altitude, leading to outbreaks, but regressions may also occur.