Public Health is the science of protecting and improving the health of communities through education, promotion of healthy lifestyles, and research for disease and injury prevention. Public health professionals analyze the effect on health of genetics, personal choice and the environment in order to develop programs that protect the health of your family and community.


Overall, public health is concerned with protecting the health of entire populations. These populations can be as small as a local neighborhood, or as big as an entire country.

Public health professionals try to prevent problems from happening or re-occurring through implementing educational programs, developing policies, administering services, and conducting research, in contrast to clinical professionals, such as doctors and nurses, who focus primarily on treating individuals after they become sick or injured. It is also a field that is concerned with limiting health disparities and a large part of public health is the fight for health care equity, quality, and accessibility.

The field of public health is highly varied and encompasses many academic disciplines. However, public health is mainly composed of the following core areas:

  • Environmental Health
  • Biostatistics
  • Behavioral Science/Health Education
  • Epidemiology
  • Health Services Administration/Management
  • Maternal and Child Health
  • Nutrition
  • International/Global Health
  • Public Health Laboratory Practice
  • Public Health Policy
  • Public Health Practice

Environmental Health

The air we breathe; the water we drink; the complex interactions between human genetics and our surroundings. How do the built and natural environments influence our health and how can we reduce risk factors? These environmental risk factors can cause diseases such as asthma, cancer, and food poisoning. Specialists from chemistry, toxicology, engineering, and other disciplines combine their expertise to answer these important questions. Environmental health studies the impact of our surroundings on our health.

Because environmental health is so broad in scope, it is often broken down in academic and professional settings in areas of contact and medians. These areas are:

  • air quality
  • food protection
  • radiation protection
  • solid waste management
  • hazardous waste management
  • water quality
  • noise control
  • environmental control of recreational areas
  • housing quality
  • vector control


Estimating the number of deaths from gun violence or looking at trends in drunk driving injuries by using math and science is the study of biostatistics. Using biostatistics, one can identify health trends that lead to life-saving measures through the application of statistical procedures, techniques, and methodology. Forecasting scenarios, identifying health trends within the community, explaining biological phenomena, as well as determining the causes of disease and injury, biostatistics are an integral part of public health. Biostatistics are often utilized in tandem with epidemiology.

Behavioral Science / Health Education

Stopping the spread of sexually transmitted diseases, such as herpes and HIV/AIDS; helping youth recognize the dangers of binge drinking; and promoting seatbelt use. Behavioral Science/Health Education focuses on ways that encourage people to make healthy choices. This includes the development of community-wide education programs that range from promoting healthy lifestyles in order to prevent disease and injury, to researching complex health issues.

Specialists encourage people to make healthy choices and develop educational programs that promote healthy lifestyles and prevent disease and injury. They also promote more efficient uses of health services, adopt self-care practices, and participate actively in the design and implementation of health programs. Some examples of concentrations include mental health, aging, health promotion and disease prevention, public health practice, health education and behavior change, disability and health, and social research.


When food poisoning or an influenza outbreak attacks a community, the "disease detectives" or epidemiologists are asked to investigate the cause of disease and control its spread. Epidemiologists do fieldwork to determine what causes disease or injury, what the risks are, who is at risk, and how to prevent further incidences. They spot and understand the demographic and social trends that influence disease and injury and evaluate new treatments. The initial discovery and containment of an outbreak, such as West Nile virus, often comes from epidemiologists. Some of the most important health-related discoveries in history are associated with epidemiology including the landmark 1964 Surgeon General's report on smoking tobacco stating its harmful effects. Biostatistics are often used in tandem with epidemiology.

Health Services Administration/Management

Managing the database at a school clinic; developing budgets for a health department; creating polices for health insurance companies; and directing hospital services all depend on health administrators. The field of health services administration combines politics, business, and science in managing the human and fiscal resources needed to deliver effective public health services. Specialization can be in planning, organization, policy formulation and analysis, finance, economics, or marketing.

Maternal and Child Health

Providing information and access to birth control; promoting the health of a pregnant woman and an unborn child; and dispensing vaccinations to children are part of maternal and child health. Professionals in maternal and child health improve the public health delivery systems specifically for women, children, and their families through advocacy, education, and research.


Promoting healthy eating and regular exercise; researching the effect of diet on the elderly; teaching the dangers of overeating and over dieting are the responsibility of public health nutritionists. In short supply in both public and private sectors, this field examines how food and nutrients affect the wellness and lifestyle of population. Nutrition encompasses the combination of education and science to promote health and disease prevention.

International / Global Health

Addressing health concerns from a global perspective and encompassing all areas of public health (e.g., biostatistics, epidemiology, nutrition, maternal and child health, etc.). International health professionals address health concerns among different cultures in countries worldwide.

Globalization has linked our health more closely to one another than ever before. The rapid movement of people and food across borders means that a disease can travel from a remote village to an urban hub at breakneck speed. Global public health meets the rising health challenges that transcend national boundaries. This international field encompasses virtually all specializations in public health.

Every school offers slightly different tracks or areas of interest. Here are examples from various schools:

  • Health-Care Finance and Economics
  • Population Policy and Demography
  • Maternal and Child Health/Primary Health Care/Health Services
  • Communication and Behavioral Science
  • Coping with Complex Emergencies
  • Mental Health and Medical Anthropology
  • Program Evaluation/Information Systems
  • Public Nutrition and Food Security
  • International Health Policy and Management
  • Infectious Disease Epidemiology and Control
  • Research and Evaluation Methods
  • Health Promotion


Public Health Laboratory Practice

Public health laboratory professionals such as bacteriologists, microbiologists, and biochemists test biological and environmental samples in order to diagnose, prevent, treat, and control infectious diseases in communities. In order to ensure the safety of our food and water, to screen for the presence of certain diseases within communities, and to respond to public health emergencies, such as bioterrorism, public health laboratory practice is essential.

Public Health Policy

Analyzing the impact of seat belt laws on traffic deaths; monitoring legislative activity on a bill that limits malpractice settlements; advocating for funding for a teen anti-smoking campaign. Professionals in public health policy work to improve the public's health through legislative action at the local, state, and federal levels.

Public Health Practice

Public health is an interdisciplinary field and professionals in many disciplines such as nursing, medicine, veterinary medicine, dentistry, and pharmacy routinely deal with public health issues. A degree in public health practice enables clinicians to apply public health principles to improve their practice.

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Another good description of public health follows:

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).

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.

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 and a part of the PHS, 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.[2]

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 specialty, while some public health programs confer the equivalent Doctor of Science degree instead. The United States medical residency specialty is General Preventive Medicine and Public Health.

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 mosquitoes.

Modern public health

As the prevalence of infectious diseases in the developed world decreased through the 20th century, public health began to put more focus on chronic diseases such as cancer and heart disease. An emphasis on physical exercise was reintroduced.

In America, public health worker Dr. Sara Josephine Baker lowered the infant mortality rate using preventative methods. She established many programs to help the poor in New York City keep their infants healthy. Dr. Baker led teams of nurses into the crowded neighborhoods of Hell's Kitchen and taught mothers how to dress, feed, and bathe their babies. After World War I many states and countries followed her example in order to lower infant mortality rates.

During the 20th century, the dramatic increase in average life span is widely credited to public health achievements, such as vaccination programs and control of infectious diseases, effective safety policies such as motor-vehicle and occupational safety, improved family planning, fluoridation of drinking water, anti-smoking measures, and programs designed to decrease chronic disease.

Meanwhile, the developing world remained plagued by largely preventable infectious diseases, exacerbated by malnutrition and poverty. Front-page headlines continue to present society with public health issues on a daily basis: emerging infectious diseases such as SARS, making its way from China (see Public health in China) to Canada and the United States; prescription drug benefits under public programs such as Medicare; the increase of HIV-AIDS among young heterosexual women and its spread in South Africa; the increase of childhood obesity and the concomitant increase in type II diabetes among children; the impact of adolescent pregnancy; and the ongoing social, economic and health disasters related to the 2004 Tsunami and Hurricane Katrina in 2005. These are all ongoing public health challenges.

Since the 1980s, the growing field of population health has broadened the focus of public health from individual behaviors and risk factors to population-level issues such as inequality, poverty, and education. Modern public health is often concerned with addressing determinants of health across a population, rather than advocating for individual behavior change. There is a recognition that our health is affected by many factors including where we live, genetics, our income, our educational status and our social relationships - these are known as "social determinants of health." A social gradient in health runs through society, with those that are poorest generally suffering the worst health. However even those in the middle classes will generally have worse health outcomes than those of a higher social stratum.[3] The new public health seeks to address these health inequalities by advocating for population-based policies that improve the health of the whole population in an equitable fashion.

The burden of treating conditions caused by unemployment, poverty, unfit housing and environmental pollution have been calculated to account for between 16-22% of the clinical budget of the British National Health Service.

Public health programs

Today, most governments recognize the importance of public health programs in reducing the incidence of disease, disability, and the effects of aging, although public health generally receives significantly less government funding compared with medicine. In recent years, public health programs providing vaccinations have made incredible strides in promoting health, including the eradication of smallpox, a disease that plagued humanity for thousands of years.

An important public health issue facing the world currently is HIV/AIDS[5]. Antibiotic resistance is another major concern, leading to the reemergence of diseases such as Tuberculosis.

Another major public health concern is diabetes. In 2006, according to the World Health Organization, at least 171 million people worldwide suffered from diabetes. Its incidence is increasing rapidly, and it is estimated that by the year 2030, this number will double.

A controversial aspect of public health is the control of smoking. Many nations have implemented major initiatives to cut smoking, such as increased taxation and bans on smoking in some or all public places. Proponents argue by presenting evidence that smoking is one of the major killers in all developed countries, and that therefore governments have a duty to reduce the death rate, both through limiting passive (second-hand) smoking and by providing fewer opportunities for smokers to smoke. Opponents say that this undermines individual freedom and personal responsibility (often using the phrase nanny state in the UK), and worry that the state may be emboldened to remove more and more choice in the name of better population health overall. However, proponents counter that inflicting disease on other people via passive smoking is not a human right, and in fact smokers are still free to smoke in their own homes.

There is also a link between public health and veterinary public health which deals with zoonotic diseases, diseases that can be transmitted from animals to humans.

The above info has been extracted from