Tuesday, November 17, 2009

Public Health

Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals." (1920, C.E.A. Winslow) It is concerned with threats to the overall health of a community based on population health analysis. The population in question can be as small as a handful of people or as large as all the inhabitants of several continents (for instance, in the case of a pandemic). Public health is typically divided into epidemiology, biostatistics and health services. Environmental, social, behavioral, and occupational health are also important subfields.

There are 2 distinct characteristics of public health:

1. It deals with preventive rather than curative aspects of health
2. It deals with population-level, rather than individual-level health issues

The focus of public health intervention is to prevent rather than treat a disease through surveillance of cases and the promotion of healthy behaviors. In addition to these activities, in many cases treating a disease may be vital to preventing it in others, such as during an outbreak of an infectious disease. Hand washing, vaccination programs and distribution of condoms are examples of public health measures.

The goal of public health is to improve lives through the prevention and treatment of disease. The United Nations' World Health Organization defines health as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity."

The focus of a public health intervention is to prevent rather than treat a disease through surveillance of cases and the promotion of healthy behaviors. In addition to these activities, in many cases treating a disease can be vital to preventing its spread to others, such as during an outbreak of infectious disease or contamination of food or water supplies. Vaccination programs and distribution of condoms are examples of public health measures.

Most countries have their own government public health agencies, sometimes known as ministries of health, to respond to domestic health issues. In the United States, the front line of public health initiatives are state and local health departments. The United States Public Health Service (PHS), led by the Surgeon General of the United States, and the Centers for Disease Control and Prevention, headquartered in Atlanta, are involved with several international health activities, in addition to their national duties.

There is a vast discrepancy in access to health care and public health initiatives between developed nations and developing nations. In the developing world, public health infrastructures are still forming. There may not be enough trained health workers or monetary resources to provide even a basic level of medical care and disease prevention. As a result, a large majority of disease and mortality in the developing world results from and contributes to extreme poverty. For example, many African governments spend less than USD$10 per person per year on health care, while, in the United States, the federal government spent approximately USD$4,500 per capita in 2000.

Many diseases are preventable through simple, non-medical methods. For example, research has shown that the simple act of hand washing can prevent many contagious diseases.

Public health plays an important role in disease prevention efforts in both the developing world and in developed countries, through local health systems and through international non-governmental organizations.

The two major postgraduate professional degrees related to this field are the Master of Public Health (MPH) or the (much rarer) Doctor of Public Health (DrPH). Many public health researchers hold PhDs in their fields of speciality, while some public health programs confer the equivalent Doctor of Science degree instead.

History of public health

In some ways, public health is a modern concept, although it has roots in antiquity. From the beginnings of human civilization, it was recognized that polluted water and lack of proper waste disposal spread communicable diseases (theory of miasma). Early religions attempted to regulate behavior that specifically related to health, from types of food eaten, to regulating certain indulgent behaviors, such as drinking alcohol or sexual relations. The establishment of governments placed responsibility on leaders to develop public health policies and programs in order to gain some understanding of the causes of disease and thus ensure social stability prosperity, and maintain order.

Early public health interventions

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 1000 BC. 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. Also, children were protected by inoculating 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 to treat smallpox.

During the 14th century Black Death in Europe, it was believed that removing bodies of the dead would further prevent the spread of the bacterial infection. This did little to stem the plague, however, which was most likely spread by rodent-borne fleas. Burning parts of cities resulted in much greater benefit, since it destroyed the rodent infestations. The development of quarantine in the medieval period helped mitigate the effects of other infectious diseases. However, according to Michel Foucault, the plague model of governmentality was later controverted by the cholera model. A Cholera pandemic devastated Europe between 1829 and 1851, and was first fought by the use of what Foucault called "social medicine", which focused on flux, circulation of air, location of cemeteries, etc. All those concerns, born of the miasma theory of disease, were mixed with urbanistic concerns for the management of populations, which Foucault designated as the concept of "biopower". The German conceptualized this in the Polizeiwissenschaft ("Science of police").

The science of epidemiology was founded by John Snow's identification of a polluted public water well as the source of an 1854 cholera outbreak in London. Dr. Snow believed in the germ theory of disease as opposed to the prevailing miasma theory. Although miasma theory correctly teaches that disease is a result of poor sanitation, it was based upon the prevailing theory of spontaneous generation. Germ theory developed slowly: despite Anton van Leeuwenhoek's observations of Microorganisms, (which are now known to cause many of the most common infectious diseases) in the year 1680, the modern era of public health did not begin until the 1880s, with Louis Pasteur's germ theory and production of artificial vaccines.

Public health nursing made available through child welfare services in U.S.Other public health interventions include latrinization, the building of sewers, the regular collection of garbage followed by incineration or disposal in a landfill, providing clean water and draining standing water to prevent the breeding of mosquitos. This contribution was made by Edwin Chadwick in 1843 who published a report on the sanitation of the working class population in Great Britain at the time. So began the inception of the modern public health. The industrial revolution had initially caused the spread of disease through large conurbations around workhouses and factories. These settlements were cramped and primitive and there was no organised sanitation. Disease was innevitable and its incubation in these areas was encouraged by the poor lifestyle of the inhabitants.

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