Omran (1971) explained the three stages of epidemiological transition starting from 1) the era of pestilence and famine to 3) the degenerative and man-made diseases via 2) the era of receding pandemics. Studies on demographic and health transition after Omran focused mainly on 1) acute infectious diseases in the era of high mortality and high fertility and on 3) non-communicable diseases (NCDs) in the era of low mortality and low fertility, while largely ignoring 2) the social hygiene and health problems during the era of receding pandemics in the midst of transition. The germ theory of Pasteur and Koch provided the scientific basis for study and control of infectious diseases. The modern risk factor epidemiology provides the scientific basis for study and control of NCDs. Then, what is the scientific basis for health problems during the demographic and health transition? In this paper the author discusses the set of genetics, racial hygiene/eugenics, euthenics and social Darwinism as the basis for study and control of variety of social hygiene problems during the era of receding pandemics. Today and in the near future of the highly aged society of post demographic and health transition with longevity, a rigorous scientific basis to support the new era is required.
