Public Health

I

Introduction

Public Health, protection and improvement of the health of entire populations through community-wide action, primarily by governmental agencies. The goals of public health are to prevent human disease, injury, and disability; protect people from environmental health hazards; promote behaviors that lead to good physical and mental health; educate the public about health; and assure availability of high-quality health services.

Public health systems vary in different parts of the world, depending upon the prevalent health problems. In the developing world, where sanitation problems and limited medical resources persist, infectious diseases are the most significant threat to public health. Public health officials devote resources to establish sanitation systems and immunization programs to curb the spread of infectious diseases, and provide routine medical care to rural and isolated populations. In industrialized nations, sanitary food and water supplies and excellent medical resources have reduced rates of infectious disease. Instead, accidents and diseases such as lung cancer, heart attacks, and strokes are among the leading causes of death. In these areas, public health goals include education programs to teach people how to prevent accidents and lessen their risk for disease, and the maintenance of the excellent disease prevention systems already established.

Public health workers may engage in activities outside the scope of ordinary medical practice. These include inspecting and licensing restaurants; conducting rodent and insect control programs; and checking the safety of housing, water, and food supplies. In assuring overall community health, public health officials also act as advocates for laws and regulations—such as drug licensing or product labeling requirements. Some public health officials are epidemiologists, who use sophisticated computer and mathematical models to track the incidence of communicable diseases and to identify new diseases and health trends. Others conduct state-of-the-art medical research to find new prevention and treatment methods.

Most people think of public health workers as physicians and nurses, but a wide variety of other professionals work in public health, including veterinarians, sanitary engineers, microbiologists, laboratory technicians, statisticians, economists, administrators, attorneys, industrial safety and hygiene specialists, psychologists, sociologists, and educators.

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II

Public Health Programs

A

Immunization

One of public health’s greatest success stories, immunization is one of the most effective weapons available to combat the spread of infectious disease. Immunization is the process of making the body resistant to a specific disease by using a vaccine, a chemical that stimulates the body to create antibodies to fight a specific infectious organism. In industrialized nations, vaccination programs protect children against measles, mumps, diphtheria, and other childhood infectious diseases. In the United States, public health agencies provide these immunizations free of charge to children from low-income families. When small outbreaks of infectious disease threaten to grow into epidemics, public health officials may initiate new vaccination programs. For example, in the late 1980s outbreaks of measles erupted in young adults who had been immunized once as infants. Public health officials recognized that these people may have lost their immunity and established a new vaccination program requiring a measles vaccination at 15 months and also at 4 to 6 years of age to boost immunity.

Several infectious diseases have been virtually eradicated by immunization programs. By 1979 a worldwide vaccination program had eliminated smallpox, a viral disease once responsible for more than 2 million deaths a year. Poliomyelitis, commonly known as polio, has been virtually eliminated from most developed nations of the world, and the incidence of tetanus, whooping cough, and diphtheria has been drastically reduced worldwide.

Global vaccination programs require extensive financial support and an army of health care professionals over long periods of time. Prohibitive costs prevent millions of children in developing countries from being immunized against measles, mumps, and other easily preventable childhood diseases. Even when resources are available, poor road and distribution systems and regional political upheavals may limit the success of vaccination programs. For example, immunization efforts to eradicate Guinea worm, a parasite that causes painful and often debilitating skin infections, have reduced annual incidence from 1 million cases in 1981 to 80,000 cases in 1997. But momentum toward complete eradication has slowed significantly because the remaining cases are primarily in western and central Africa, especially in the Republic of the Sudan, where civil war interferes with national and international public health efforts to eliminate the disease. The United Nations estimates that up to 4 million lives could be saved annually if existing, but under-used vaccinations were fully implemented.

B

Rural and Urban Health Clinics

Public health agencies operate local clinics that provide free or reduced-cost medical services to individuals, especially infants and children, pregnant and nursing women, migrant farm workers, and people with drug abuse problems, physical disabilities, and other conditions. These clinics provide prenatal and pediatric care for children who have no regular access to medical care. The clinics may provide visiting nurse and other home health care services for the elderly. Public health clinics may also offer rehabilitation programs for people addicted to drugs or alcohol.

In developing countries and in rural and low-income communities in industrialized nations, public health clinics may be the only source of routine medical care. Members of the community go to clinics for regular exams or for treatment when they are injured or ill, as well as for immunizations and other public health services. Clinics may provide free or low-cost medications, such as antibiotics or birth control pills. Often, community members may obtain counseling on health matters, such as proper infant nutrition, safe food handling procedures, or family planning advice.

Public health clinics routinely screen patients for a number of infectious diseases, such as sexually transmitted infections, and may provide free treatment if patients test positive. Each clinic tracks the incidence of certain communicable diseases in its area, and reports this information to national and international public health offices. Public health clinics may also track down past sexual partners of STI patients, inform them that they may have been infected with an STI, and urge them to come in to a clinic to be tested.

C

Disease Tracking and Epidemiology

One branch of public health, epidemiology, studies the incidence of disease in large populations. Epidemiologists study data from public health clinics and private physicians who are required by law to report cases of certain diseases and deaths to public health officials. Using clues about the patterns in which deaths and diseases occur, epidemiologists are able to identify emerging disease patterns that may indicate environmental health hazards, potential outbreaks of existing diseases, or emergence of new infectious diseases. For example, in the early 1980s a few doctors in New York and California reported an unusually high number of deaths from opportunistic infections—infections by organisms that usually only cause disease in people with weakened immune systems. These early reports prompted epidemiologists and medical researchers to investigate this new vulnerability to opportunistic infections, which they called acquired immunodeficiency syndrome (AIDS). These efforts led to the identification of the previously unknown human immunodeficiency virus (HIV), the virus that causes AIDS.

Threats to public health concerns change over time and epidemiologists and other officials continuously evaluate epidemiological trends to determine how best to meet future public health needs. For example, recent epidemiological reports show that tuberculosis, an infectious disease believed to be under control just 30 years ago, is now responsible for more deaths worldwide than any other infectious disease, killing more people per year than AIDS and malaria combined. This resurgence is due to new drug-resistant strains of the bacteria that cause tuberculosis. The tuberculosis epidemic, or pandemic, has been declared a global public health emergency, prompting intensive international public health efforts to curb its spread.

Epidemiologists and other public health officials attempt to break the chain of disease transmission by notifying people who may be at risk for contracting an infectious disease. When epidemiologists learn that a restaurant worker has infectious hepatitis, they place announcements in local media, such as radio and newspapers, urging people who ate at the restaurant in recent weeks to be checked for the disease and to seek treatment so that they will no longer risk infecting others.

Organizations such as the World Health Organization (WHO), an agency of the United Nations, monitor infectious diseases and try to prevent outbreaks from spreading worldwide. In early 2003 WHO epidemiologists learned that a deadly type of pneumonia of unknown cause that originated in China was quickly spreading to other countries. The disease, known as severe acute respiratory syndrome (SARS), begins with a fever, chills, headache, and malaise. Two to seven days later some people develop a dry cough and difficulty breathing and, in some cases, die. In March 2003 WHO issued an international alert, designating SARS as a worldwide health threat. The alert triggered public health officials from nations around the world to establish procedures to identify and isolate SARS cases and possibly prevent the illness from reaching epidemic proportions.

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