Public health is an aspect of health services concerned with threats to the overall health of a community based on population health analysis. It generally includes surveillance and control of infectious disease and promotion of healthy behaviors among members of the community. Prevention is another important principle: both vaccination programs and free distribution of condoms are public health measures. Public health promotes not simply the absence of disease but mental, physical, and emotional well-being. The WHO sets standards and provides global surveillance, but national bodies such as the Centers for Disease Control and Prevention in Atlanta, Georgia in the U.S.A. and their local affiliated Medical Officer of Health are usually the lead in responding to public health threats. The frontline on public health initiatives are state and local health departments.The major degree in Medicine related to this is The Master in Public Health (M.P.H.), while the Residency specialty is Community or Public Health Medicine.
History of public health
In many ways, public health is largely a modern concept, although it has roots in antiquity. The development of public health policies and programs required governments to gain some understanding of the causes of disease. Early on in human civilization, it was recognized that polluted water and lack of proper waste disposal may spread vector-borne diseases. By Roman times, it was well understood that proper diversion of human waste was a necessary tenet of public health in urban areas.
The Chinese developed the practice of variolation following a smallpox epidemic around 1,000 B.C.. An individual without the disease could gain some measure of immunity against it by inhaling the dried crusts that formed around lesions of infected individuals. Similarly, children were protected by innoculating a scratch on their forearms with the pus from a lesion. This practice was not documented in the West until the early 1700s and was used on a very limited basis. The practice of vaccination did not become prevalent until the 1820s, following the work of Edward Jenner.
During the 14th century Black Death in Europe, it was believed that removing bodies would prevent further spread of the disease. Unfortunately, this did little to stem the plague, which was spread by rodent-borne fleas. Burning areas of cities resulted in much greater benefit, since it removed the rodent infestations. The development of quarantine in the medieval period helped mitigate the effects of other infectious diseases.
The science of epidemiology was founded by John Snow's identification of a polluted public water well as the cause of an 1854 cholera outbreak in London. John believed in the germ theory of disease as opposed to the prevailing miasma theory, which taught correctly that disease was a result of poor sanitation, but was based only upon the prevailing theory of spontaneous generation. This was the case, even though Redi showed in the 17th century that fly eggs were required for maggots to be generated in dung heaps and Lazzaro Spallanzani, in 1768, proved that microbes came from the air, and that regeneration could be prevented by boiling in a hermetically sealed container.
Microorganisms were first observed around 1680 by Anton van Leeuwenhoek, but it was not until the 1880s that the culmination of the germ theory of Robert Koch and Louis Pasteur and the production of artificial vaccines revolutionized the study of infectious disease and introduced the modern era of public health.
Public health programs
Nowadays, most governments recognize the importance of public health programs in reducing the incidence of disease, disability, and the effects of aging. Public health programs providing vaccinations have in recent years have all but eradicated smallpox. Certainly, one of the most important public health issues of the present is that of AIDS.
A controversial aspect of public health is that related to the control of smoking, which is often described as "the most important public health issue". Many states are planning or implementing major initiatives to cut smoking, such as increased taxation and bans on smoking in some or all public places. Proponents argue that smoking is one of the major killers in all developed countries, and that they have a duty to reduce the death rate, both through limiting passive smoking and by providing less opportunities for smokers to smoke. Opponents say that this undermines individual freedom and personal responsibility, in the UK often using the phrase nanny state, and worrying that the state may take power to remove more and more choice in the name of statistically averaged good health. It is likely that public health initiatives throughout history were attended by similar controversies that history has forgotten.
Economics of public health
The application of health economics to the realm of public health has been rising in importance since the 1980s. Health economics studies can show, for example, where limited public resources might best be spent to save lives or cause the greatest increase in quality of life.