Public Health

D

Sanitation and Pollution Control

Disease-causing organisms are often transmitted through contaminated drinking water. The single most effective way to limit water-borne diseases is to ensure that drinking water is clean and not contaminated by sewage. In many parts of the world, public health officials establish sewage disposal and solid waste disposal systems, and regularly test water supplies to ensure they are safe. These systems are expensive to develop and maintain, however, and many developing nations have poor or insufficient water sanitation systems. The United Nations estimates that between 5 and 10 million people die each year from water-borne diseases such as cholera.

Many diseases, such as hepatitis A and those caused by the Salmonella bacteria, are transmitted through food. When food is not washed or thoroughly cooked, or when food is stored at temperatures that are hospitable to disease-causing organisms, people who eat the food are subject to infection. Public health programs establish and enforce laws for safe food storage and preparation. For example, in most nations food-processing plants, restaurants, and grocery stores are legally required to follow strict food-safety guidelines established by public health officials.

Public health officials also establish and oversee programs to control flies, rats, and other animals that spread disease-causing microbes. For example, pesticide programs in parts of Africa significantly reduced rates of trypanosomiasis, a sometimes fatal disease commonly known as sleeping sickness that is transmitted by the African tsetse fly. Several often deadly diseases are transmitted by rodents. Hantaviruses transmitted by mice, for example, can cause a deadly type of severe respiratory disease. Humans are infected when they inhale dust containing virus-infected rodent feces. By preventing rodents from living in or near human dwellings, public health officials seek to reduce rates of these types of infections.

Environmental pollution is another preventable cause of disease and disability, and in most countries public health officials address the adverse health effects of air pollution and water pollution. Public health officials may work in conjunction with pollution control organizations to establish and enforce pollution limits and advise the general population when pollution levels exceed safe limits. For example, when air pollution reaches harmful levels in Los Angeles, California, public health and environmental officials warn the public of the potential dangers. When chemical contamination renders ponds or lakes unsafe for swimming, health officials post warning signs informing the public of the hazard. They may close down businesses that consistently put harmful pollutants into the environment, or prohibit distribution and sale of food harvested from contaminated regions.

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E

Medical Research

Another component of public health is scientific and medical research. A cadre of doctors and scientists work in laboratories around the world to establish new ways to prevent, diagnose, treat, and cure disease and disability. For example, over 30,000 different biomedical research projects are underway in the United States to investigate diseases such as AIDS, cancer, Alzheimer’s disease, and even the common cold. Other projects investigate the safety and effectiveness of existing pharmaceuticals and treatment programs, and test the safety of hundreds of the products that we use everyday, such as new food products, household cleaners, and nonpolluting forms of gasoline.

Scientists and doctors employed by the government conduct some biomedical research in public health facilities. In other cases, biomedical research projects beneficial to public health, but conducted by nongovernmental scientists, receive public health funding to help cover the expenses associated with the research. These research projects may be conducted by university professors, doctors and scientists at hospitals, and even private biomedical research firms, all working to find better ways to protect human health.

F

Public Education Campaigns

Many diseases are preventable through healthy living, and a primary public health goal is to educate the general public about how to prevent noninfectious diseases. Public health campaigns teach people about the value of avoiding smoking, getting treatment for high blood pressure, avoiding foods high in cholesterol and fat, and maintaining a healthy body weight. Other campaigns educate the public on ways to prevent birth defects, such as abstaining from alcohol during pregnancy to prevent fetal alcohol syndrome.

A broad area of public health education, called health promotion, places special emphasis on illness and disabilities that decrease the quality of life. Health promotion efforts in the 1990s, for instance, increased public awareness of osteoporosis, a condition that causes disabling bone fractures among older women. Programs educated women about how to maintain strong bones by including enough calcium in their diets, exercising, and to consider estrogen replacement therapy after menopause. Health promotion also encourages people to take advantage of early diagnostic tests that can make the outcome of disease more favorable. Regular mammograms encourage early detection of breast cancer, for instance, increasing the chances of a cure. Detection and proper treatment of high blood pressure reduces the risk of a stroke, the leading cause of permanent disability in older people.

Accidents, particularly automobile accidents, pose a major threat to public health, and officials have undertaken campaigns to reduce the number of automobile accidents by encouraging seat belt use and discouraging drinking and driving. Violence, especially domestic violence and handgun accidents, is often regarded as a public health problem and public health departments sponsor family violence prevention programs and handgun safety programs.

III

Public Health Agencies

On an international scale, public health is overseen by the World Health Organization (WHO). WHO manages international disease prevention and control efforts, and is involved in training medical personnel, educating world populations about public health issues including widespread diseases, nutrition, population control, and the benefits of environmental sanitation. WHO and all of its programs are funded by United Nations membership dues and contributions, and voluntary donations from public and private sources.

In the United States, the Department of Health and Human Services (HHS) oversees public health and welfare throughout the nation. It is funded by American citizens through taxes. The Public Health Service, which is part of HHS, is the main federal agency concerned with public health. The Public Health Service is divided into several individual agencies that specialize in different aspects of public health. The National Institutes of Health, the medical research arm of the Public Health Service, conducts biomedical research and maintains 25 institutes and centers of health and the National Library of Medicine. The Centers for Disease Control and Prevention (CDC) monitors and prevents outbreaks of diseases, maintains national health statistics, and administers many of the public immunization programs in the United States. The Food and Drug Administration (FDA) assures the safety of food, pharmaceuticals, cosmetics, and medical devices through legislation and licensing programs.

Each state in the United States has its own department of health and most local communities have a city or county health department as well. State and regional public health departments work with national agencies to administer public health programs. Other government agencies, such as environmental protection departments, also may have some responsibilities for public health. Hundreds of private or voluntary health organizations contribute to overall community health by educating the public about good health practices and prevention of heart disease, cancer, and other conditions.

Although most industrialized countries follow this general pattern for administration of public health services, there are individual variations. In the United States, for instance, social welfare programs, such as financial aid to poor families, are separate from public health, while in the United Kingdom, health and welfare services are combined. Differences also exist in public health financing. The United Kingdom, Canada, Switzerland, Japan, and most other industrialized countries have national health systems that provide free individualized medical care as well as public health services. In the United States, most public health services are provided by the government without charge, but individual medical care is primarily paid for by individuals or by health insurance.

Developing countries usually have small, poorly financed public health services. In many of the world's poorest countries, especially in sub-Saharan Africa, there is less distinction between public health and routine individual medical care. A national ministry of health usually provides all health services through a system of regional health centers. Regional medical officers administer medical programs in each region, overseeing populations of about 100,000 people. Health centers, staffed by nonphysicians with medical training, often serve populations of 10,000 to 20,000 people dispersed throughout many villages. Some villages have health outposts called dispensaries, where villagers can go for medicine, vaccinations, and other basic medical services. But many medical services readily available in the industrialized world, such as high-tech diagnostic tests or expensive medicines, are not available in developing countries.

IV

History of Public Health

People in ancient societies were concerned about personal hygiene and sanitation for religious reasons. The Bible contains many rules for cleanliness, and describes public health measures still important today. These include quarantining the sick to prevent the spread of disease and avoiding contact with objects used by sick people.

The Greek physician Hippocrates first made the connection between disease and natural environmental factors in the 4th century bc. His treatise Airs, Waters, and Places described how diseases can result from way of life, climate, impure water, and other environmental factors. For the next 2000 years, it was the most widely used text on public health and epidemiology.

Ancient Romans adopted Greek ideas about public health after colonizing Greece in the 1st century bc. Rome's greatest contributions to public health involved sanitary engineering. They built aqueducts to supply Rome with pure water and a public sewer system to carry away wastes, as well as public baths and hospitals. The Roman government also hired physicians and assigned them to villages to care for the poor.

After the Roman Empire collapsed in ad 476 public health efforts were forgotten and unsanitary conditions returned. Millions of people died when great epidemics of smallpox, leprosy, bubonic plague, tuberculosis, and other diseases swept across Europe in the Middle Ages (5th to 15th centuries ad). The first modern advances in public health occurred as officials tried to cope with disease epidemics. They used tactics including quarantining sick people to prevent the spread of disease; disinfecting objects that came into contact with the sick; and establishing observation stations to monitor outbreaks of disease. City officials also realized the importance of disposing of human wastes and garbage, which previously were thrown into the street where they attracted flies and rats; and providing clean drinking water.

In the 19th and 20th centuries, efforts to improve sanitation, especially in big cities, have had a major impact in improving human health and increasing life expectancy. Many medical advances, including the introduction of antibiotics and vaccines, became important tools of public health. The first health departments were established in cities and rural areas. In the United States, public health measures to prevent the spread of infectious disease were so effective that by the late 1970s, U.S. health experts expected to eradicate infectious disease by the end of the 20th century.

In the 1980s, however, public health officials realized that infectious diseases remained a major international threat. Tuberculosis and other infections, once regarded as under control, appeared in forms resistant to conventional antibiotics. New infectious diseases, such as AIDS and new forms of hepatitis, took the world by storm. A global epidemic of AIDS began in 1981, and intensive, multibillion dollar global efforts to curb the spread of AIDS continue to dominate the public health front. International education campaigns have significantly reduced the spread of AIDS in many regions of the world. Although medical research has produced promising drugs (though often prohibitively expensive), no cure has been found and intensive multinational efforts to find a cure or a vaccine for AIDS continue.

Experts predict that viruses yet undiscovered may pose the greatest challenges to public health yet. Global population levels are increasing at exponential levels, and the pressing need for food and housing results in the clearing of previously uninhabited tropical forests at equally alarming rates. In this process, humans are exposed to disease-causing viruses previously confined deep within tropical rain forests. Because humans have never before been exposed to these viruses, experts predict that we will have no natural immunity to them, and they may have devastating health effects.

New viruses will spread faster and more efficiently than ever before. In the past, geographic barriers confined outbreaks to particular regions because those infected were not able to make the often arduous trips across mountain ranges, deserts, or oceans. But efficient and affordable airplane travel has virtually eliminated these barriers to transmission–it is now possible for someone to be exposed to a deadly virus and travel across the globe before showing signs of infection. Future public health efforts will have to address ways to manage global outbreaks of new diseases in a world more densely populated than ever before.

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