Public health was defined by the American public health leader, Charles-Edward A. Winslow, in 1920 as, “the science and art of preventing disease, prolonging life, and promoting physical health and efficiency through organized community efforts for the individual in principles of personal hygiene, the organization of medical and nursing service fro the early diagnosis and preventive treatment of diseases, and the development of the social machinery which will ensure to every individual in the community a standard of living adequate for the maintenance of health.” Although a modern nosologist would add mental to physical aspects of health, Winslow’s definition has not been superseded. It provided the basis for the World Health Organization’s definition of health: “A state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity” (1948).
During the Dark ages (about 500-1000 C.E), Western Europe experienced a period of social and political disintegration. Large cities disappeared, replaced by small villages surrounding the castles of feudal chiefs. The only unifying force was Christianity, and it was in the monasteries that the learning and culture of the Greco-Roman world was preserved. Furthermore, in many of these institutions, piped water supplies, sanitary sewers, privies, bathing facilities, and heating and ventilation were provided. In addition, some monasteries constructed hospices to shelter travels and sick persons, though the medical care provided in them was primitive at best
The Renaissance and The Plague Centuries It was during the Renaissance, a period of great commercial, scientific, cultural, and political development, that the bubonic plague, or “Black Death,” swept over Europe and the Near East killing and estimated one-fourth to one-third of the population between 1347 and 1351. For the following two-and-a-half centuries, periodic epidemics of plague decimated these populations.
The Enlightenment (the period from 1750 until the mid-nineteenth century) was characterized by unprecedented industrial, social, and political developments, and the resulting societal impacts were immense, culmination in the Industrial Revolution. It was in Germany that the first major contribution of the period to public health occurred. Between 1779 and 1816, Johann Peter Frank, a leading clinician, medical educator, and hospital administrator, published a six-volume treatise, System of a Complete Medical Policy, in which he proposed a sweeping scheme of governmental regulations and programs to protect the population against disease and to promote health. His proposals covered the entire life span from birth to death. The actions that he advocated ranged from measures of personal hygiene and medical care to environmental regulation.
Edwin Chadwick documented the status of housing of the working population, the lack of sewerage and adequate supplies of water, the unhygienic circumstances of places of work, the life expectancy of various Social classes, the economic impact of unsanitary conditions, and the evidence for the beneficial health effects of preventive measures. As a result, sewerage, potable and plentiful water supplies, refuse disposal, proper ventilation of residence and places of work, supervision of public works by qualified professionals, and legislative authorization of measures to obtain these results were put forward.
Bacteriology: With the discoveries of pathogenic bacteria by Louis Pasteur in France and Robert Koch in Germany in the late 1870s and early 1880s, the science of microbiology was born. Consequent developments in immunology and parasitology provided epidemiologists and other public health workers with the tools to study and understand epidemic phenomena. Sanitation could become science based and the development of vaccines promised the prevention of many infectious diseases. A new era of rational public health was established.
Colonialism and Public Health: From the sixteenth through the nineteenth century, European countries had competitively colonized most of the tropical world. The contagious diseases they brought with them frequently ravaged indigenous populations. Conversely, the prevalent diseases of colonized areas threatened the invaders. Colonial sanitation and medical care was originally designed to serve the interests of the colonists. However, after the establishment of biomedical science, there was enhanced incentive to control the major tropical diseases that were interfering with the economic development of the colonies (e.g., malaria and yellow fever). In India, in 1897, Ronald Ross identified the mosquito vector of malaria, leading to the partial control of the world’s most prevalent endemic disease and vastly increasing the agricultural output and, incidentally, the population of the subcontinent.
Although the Sanitary movement of the nineteenth century and the development of bacteriology substantially lowered death rates from enteric diseases, other serious health problems still existed. One was the appalling and ubiquitous rate of infant mortality. First in Europe, then in Britain and in the United States, maternal and child health programs were initiated with an emphasis on nutrition, medical care, and, eventually, health inspection in schools. High rates of occupational diseases and industrial injuries led to programs for industrial hygiene and occupational health. Mental health was identified as a public health issue, and specific nutritional deficiencies were recognized as risk factors for a spectrum of diseases. Furthermore, pioneering studies of pellagra, a vitamin-deficiency disease, by Joseph Goldberger and Edgar Sydenstricker, revealed the complex environmental, social, and biological interactions responsible for the occurrence and distribution of such diseases. Voluntary health agencies evolved in the late nineteenth and early twentieth centuries in Europe and North America, growing out of the failure of public health organizations to fully apply knowledge created by the new biomedical sciences, and by the continuing deplorable condition of the urban poor.
The Late Twentirth Century
In the last half of the twentieth century, public health continued to expand its established roles. However, new forces were at work to further broaden its purview. Among these were the aging of the populations in industrialized regions, recognition of the importance of behavioral factors in determining the health of populations, exacerbation of social inequalities in health, increasing violence (at the domestic level as well as at the civil and international level), and globalization.
As infant and child mortality declined in the industrialized countries, life expectancy and the proportion of the elderly in populations increased. Consequently, diseases such as heart diseases and cancer became more importanct. Other behavioural factors, such as diet, exercise, and obesity, were found to be causally associated with several other diseases. Ameliorating adverse behavioral risk factors has become a major function of public health agencies.
Since the mid-nineteenth century, the relationship between socioeconomic status and health has been widely recognized. However, in the late twentieth century epidemiological research has pointed out additional differences in health status between gender, ethnic, and occupational groups. Such inequalities appear to be increasing and are being recognized as a major challenge for modern public health. Increased globalization and technological advances have resulted in worlwide economic, political, and social interdependence. However, recognition of the interdependence of regions and nations with respect to health and disease was institutionalized in 1902, when the Pan American Health Organization was estblished to coordinate communicable disease surveillance and quarantine in the western hemisphere. By the end of the century, the major global public health problems included the manifold consequences of atmospheric warming.
Epidemic smallpox was one of the deadliest scourges ever to afflict humankind. It killed ancient Egyptian Pharaohs, villagers in teeming Asian villages, aristocrats in Paris and St. Petersburg, and children in colonial New England. It contributed substantially to the collapse of the Aztec empire in Mexico, where it was introduced by the Spanish conquistadors. It was an ever-present threat, always lurking, occasionally breaking out in large epidemics. Smallpox occurred in two forms, variola major and variola minor. Variola major was the fulminant, often epidemic, variety, with a mortality rate of 40 percent or more and severe complications among survivors. Variola minor was milder, with a mortality rate of less than 5 percent.
In 1798, Edward Jenner, a Gloucestershire doctor, vaccinated a boy with secretions from a cowpox blister, and soon reported successful vaccination of over twenty others. This was the prelude to the twentieth-century eradication of smallpox in a worldwide vaccination campaign coordinated by the World Health Organization. The last naturally occurring case was a girl in Somalia in 1977 (two further laboratory cases occurred in England in 1978).
Smallpox was an acute illness with high fever, a widespread skin rash with blebs and blisters, generalized prostration, collapse, and, commonly, death. Survivors often carried disfiguring scars for the rest of their lives, and were usually blind if lesions affected their eyes. The cause was a brick shaped virus in the orthopox virus family. Humans were its only natural host. The virus survives now only in tissue cultures in two or three high-security microbiology research institutes. Total eradication was made possible by unique epidemiological features-i.e., there is no non-human host and vaccination was rapidly efficacious, so those who had been exposed to a case were protected from infection if they were immediately vaccinated. This was the basis for the containment strategy that was ultimately the key to global eradication.
The WHO estimates that 10% of the child and adult populations worldwide suffer from mental disorders at any one time, with mental disorders accounting for four of the ten leading causes of life lived with disability. The Lancet medical journal recently published a major series of articles-11 commentaries and 6 reviews-on global mental health, with a focus on mental disorders in low and middle income countries. In summary, the evidence collated in this Series, points to these facts: