Epidemiology is the course and analysis of the patterns, source and effects of health and epidemic conditions in specified populations. It is the keystone of civic health and shapes management decisions and data-based practice by identifying exposure factors for disorder and mark for precautionary healthcare. Epidemiologist’s assisted with study method, selection, and statistical analysis of evidence; alter interpretation and propagation of results. Epidemiology has helped evolve technique used in clinical research, civic health course and to a lesser intensity, basic research in the biological system.