Human concern with health dates back to the earliest writings and civilizations. Excavations of Mohenjo Daro and Harappa in the Indian subcontinent reveal bathrooms and drainage systems more than 4,000 years old. Hygiene is a vital component of many religions, governing the cultural and culinary traditions of numerous societies. In addition, people throughout history have considered illness, especially plagues, a judgment or punishment from god(s).

The great writers, philosophers, and physicians of ancient Greece tell us of the beginnings of public health. Hippocrates in ‘Airs, Waters and Places’ distinguished between endemic and epidemic diseases and the factors affecting them, including climate, soil, water, mode of life, and nutrition. He also discussed the link between health and the environment, suggesting conditions to avoid and others to seek ...