The treatise on "Airs, Waters, and Places", written about 400 B.C. and part of the Corpus Hippocraticum, represents a first attempt to find natural causes for the health and diseases of whole populations of different regions. The author tries to investigate the impact of the winds, the changes of the seasons with their shift from warm to cold and vice versa, and the qualities of food and drinking water. The reasons given in the tract appear to our mind sometimes awkward and farfetched. Galen of Pergamon (129-46 A.D.) wrote six hundred years later a commentary where he endevoured to reconcile the statements of his venerated predecessor with his own doctrines of humoral pathology. But he also does not spare him some criticism, e.g when the Hippocratic author erroneously maintained that an artificially deformed shape of the skull may be imparted from fathers to their offspring.
The author of the Hippocratic treatise "Airs, Waters, Places" associates seasons, prevailing winds, and the quality of the air and water with the physical condition of people and the occurrence of disease. He advises the physician coming upon a city that is new to him to take note of the environmental factors that determine the kinds of diseases endemic to that location. He characterizes the properties of water, soil, and human behaviors and relates them to epidemiology and the maintenance of human health. In his opening chapter, for example, he advises the physician to consider what effects each season of the year can produce because each season and each change of season differ from the others. As the year passes, physicians will be able to tell what epidemic diseases will arise in the summer and what in the winter, and they will be able to distinguish seasonal diseases from those arising out of an individual's mode of life. Today the principles advocated in this early description of environmental influences on epidemiology and disease are routinely applied.
Epidemiology today uses the principles of risk assessment (hazard identification, dose/response assessment, exposure assessment, and risk characterization) to estimate health risks and develop an appropriate scientific response to protect public health . The modern use of sophisticated quantitative methodologies and epidemiological determinants has, nevertheless, validated the Hippocratic observations that seasonal variations influence the incidence of disease.
The clinical spectrum of foodborne disease, with limited exceptions, supports the seasonal concept. In industrial countries with temperate climates, it is a commonplace that respiratory infections, colds, and influenza are associated with the winter months. Most food-associated cases occur in the warm months. In the United States, outbreaks of foodborne illness are reported most frequently during the warm months, from May through September. Salmonella is most frequently cited as the causative organism . Even in the tropics, where foodborne infections appear endemic, many of the acute diarrheal episodes are distributed seasonally, with the highest frequency during the early rains or at the beginning or height of the monsoon.
Relevance of Water to Disease Causation
The Hippocratic author also noted the influence ...