[Climatic changes and transmissible diseases]

Transmissible disease geography can be defined as the study of the spatial expression of pathogenic processes. The three main elements implicated in this study are environmental conditions affecting biophysical dynamics, political, economic, social, and cultural events, and evolution of pathogenic agents under the influence of the first two factors. A number of pathogenic areas or regions can be delimited in function of different combinations of these factors. These territories are subject to rapid change and variation. Meteorological changes and cycles are contributing factors. However the underlying mechanisms appear to be increasingly affected by human activity. Several disturbing signs have been attributed to man including desertification, drought, and global warming, but the cause-and-effect relationship is unsure. Much research is in progress but resulting data remains contradictory except insofar as to confirm the complexity of atmospheric phenomena. The natural geography of transmissible diseases is affected by these variations but it is mainly the expression of the dialogue between man and nature.