Pathogenesis and ecology: the case of cholera.

The way in which the results of various studies of cholera have influenced the understanding of the disease are discussed. Attention is given to the outcomes of medical research, targeted on problems of cholera and biological research focused on understanding Vibrio cholerae. The contrast between these approaches has produced a new understanding of the ecological nature of disease. The importance of the environmental reservoir of V. cholerae as the engine for the generation of diversity is highlighted.