Introduction to public health
Definition, Scope, and Achievements of Public Health
According to the World Health Organization, public health “refers to all organized measures—whether public or private—to prevent disease, promote health, and prolong life among the population as a whole.” As this definition stipulates, the focus of public health activities is on the health of entire populations, not on individual patients. Dimensions of health accordingly encompass “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.” The domain of public health activities extends from local to national levels. Moreover, global public health responses involve cross-border health risks, including pandemics, climate change, famine, and displaced populations.
Public health has roots in ancient history; examples of such include initiatives by the Chinese and Romans. About 1000 bc , Chinese doctors developed the practice of variolation (inoculation of fluid from pustules as an attempt to immunize against disease), following a smallpox epidemic. Further, as early as 310 bc , the Romans exhibited a public health philosophy. They believed that cleanliness would lead to good health and thus made links between causes of disease and methods of prevention. For example, during this time, an association was made between the increased death rate of persons living near swamps and sewage. As a result, the Roman Empire began working on two major public health projects in sanitation control: the building of aqueducts to supply clean water to the city, and a sewage system to eliminate waste from the streets. Nowadays, programs promoting hand washing, breast-feeding, vaccinations, and distribution of condoms to control the spread of sexually transmitted diseases are examples of common public health measures.
Today, the benefits of public health infrastructure in the United States and abroad continue to strengthen the well-being of society. The effect of interventions has been great. In the twentieth century, the 10 greatest public health achievements have been documented, as follows :
Vaccination programs (i.e., eradication of smallpox, elimination of poliomyelitis in the Americas, and control of measles, rubella, tetanus, diphtheria, and other diseases around the world)
Motor vehicle safety
Control of infectious diseases
Decline in deaths from coronary heart disease and stroke
Safer and healthier foods
Healthier mothers and babies
Fluoridation of drinking water
Recognition of tobacco use as a health hazard
Public Health System and Infrastructure
A public health system is defined as “all public, private, and voluntary entities that contribute to the delivery of essential public health services within a jurisdiction.” Hospitals, clinics, and primary health care centers are the frontline of public health service delivery; however, the public health system goes beyond the health facilities alone. In fact, it encompasses all of the sectors that have effects on the health of populations. These include housing, agriculture, the economy, etc. The term social determinants of health (SDH) addresses the conditions in which people are born, grow, live, work, and age. To work in such a multidisciplinary context, contemporary public health practice requires multidisciplinary education, training, and participation of scientists and professionals from other disciplines, such as sociology, community development, communications, geography, climatology, ethics, and law.
Many efforts have been made to institutionalize public health policies and practices. Public health legislation began to be consolidated in the mid-eighteenth century in Europe and North America. The American Public Health Association (APHA), founded in 1872, is recognized as the oldest organization of public health professionals worldwide. However, the World Health Organization (WHO), established in 1948, is the lead agency on global public health issues.
Although the private sector, along with the charities and nongovernmental organizations (NGOs), plays a significant role in provision of health care to communities, the ultimate responsibility for the overall performance of a country’s health system lies with the government. Most countries have their own governmental public health agencies, sometimes known as ministries of health (MoH) or ministries of public health (MoPH). Other examples are the Ministry of Health & Family Welfare in India and the Ministry of Health and Medical Education (MoHME) in Iran that resulted from integration of the MoH and higher education system of health sciences. In Canada, the Public Health Agency (PHA) of Canada, reporting to the Minister of Health, is the national agency responsible for public health. This responsibility lies with the National Health Services (NHS) in England, under the Department of Health.
Formal public health programs in the United States have existed for well over 200 years. For example, the origins of the U.S. Public Health Service (USPHS) (initially known as the Marine Hospital Service) may be traced to the passage of an act in 1798 that provided for the care and relief of sick and injured merchant seamen. After its inception, and over the next 200 years, the Marine Hospital Service was restructured to provide a wider variety of essential services. Now the USPHS is recognized worldwide and is working alongside its other federal partners and state agencies, including the Department of Health and Human Services (DHHS) and its agencies, such as the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the U.S. Department of Agriculture (USDA). The USPHS encompasses a broad integration of commercial, public, government, and nongovernment entities. It is as diverse as the very population it serves. It includes government public health agencies operating on federal, regional, state, and local levels; health care delivery infrastructure, such as hospitals and clinics; public health and health science academic institutions; community entities, such as schools, organizations, and religious congregations; commercial businesses; and the media. Public health is also augmented by its partnerships and increasing collaboration with expert military health institutions, such as the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) and other defense agencies; national institutions such as the National Institute for Allergy and Infectious Diseases (NIAID) under the National Institutes of Health (NIH); law enforcement and emergency responder communities on federal (Federal Bureau of Investigation) and local levels; and the medical-legal community, which is composed of national medical examiners offices and forensic scientists.
Public Health Essential Services
The mission of public health is to fulfill society’s desire to create conditions such that people can be healthy. The public health—at any level of operations—relies on the following main interdependent and cyclical pillars: (1) assessment of the population’s health, (2) formulation of public policies, and (3) assurance of the population’s access to appropriate and cost-effective care. These pillars have been extended by the U.S. National Public Health Performance Standards (NPHPS). They are described as the 10 essential public health services, which include the following :
Monitoring health status to identify and solve community health problems
Diagnosing and investigating health problems and health hazards in the community
Informing, educating, and empowering people about health issues
Mobilizing community partnerships and action to identify and solve health problems
Developing policies and plans that support individual and community health efforts
Enforcing laws and regulations that protect health and ensure safety
Link people to needed personal health services and assure the provision of health care when otherwise unavailable
Assuring a competent public and personal health care workforce
Evaluating the effectiveness, accessibility, and quality of personal and population-based health services
Researching for new insights and innovative solutions to health problems
Similar to traditional programs in public health, ranging from maternal and reproductive health to injury control and prevention, the public health relation with disaster management also fulfills the above-mentioned essential services. This introductory chapter explains why disasters are important to public health and how the public health system interacts with the disaster-management cycle. In the subsequent chapters of this textbook, the reader may find elaborative information on applications of the public health functions in disasters, including needs assessment, surveillance, public information management, safety of health workers, etc.
Public health consequences of disasters
Each year millions of people worldwide suffer from disasters, both in developed and less-developed countries. Disasters affect the health of populations not only directly but also indirectly, via damages to health care systems, infrastructures, and disruption of social and living conditions. The effects vary disaster by disaster and depend on the type and intensity of the hazard, population density, extent of damage, and response operations. The effects of disasters on public health can be classified in the following four categories, as summarized in Table 2-1 .
|Ppopulation’s health||Health care system|
Direct Effect on the Health of Population
Death and physical injury are the most significant effects of disasters on health. From 2000 to 2013, natural disasters killed about 1.2 million people worldwide. Different disasters result in different levels of mortality. The highest rate of mortality usually occurs following earthquakes, flash floods, and tsunamis.
Mechanisms and patterns of injury vary by disaster. Some natural disasters have predictable injury patterns, as described in more detail elsewhere in this book. Earthquakes and high-wind events can lead to severe blunt- and penetrating-trauma injuries requiring intensive care. Further, crush syndrome occurs commonly following earthquakes, requiring responders to provide robust dialysis capabilities. Building collapse is the most common cause of injury and death from earthquakes. In tropical cyclones, drowning from storm surges occurs frequently. Flooding and mudflows are also expected causes of death following the storms. In high-wind events, flying debris causes blunt trauma and the structural collapse of buildings, which can kill people. Blasts caused by terrorism activities or other types of human-made disasters also are capable of producing high fatality rates and severe injuries.
Disasters can also generate acute illnesses in an exposed population. Examples include coccidioidomycosis caused by exposure to soil containing spores, pulmonary alveolar proteinosis caused by exposure to dust following an earthquake, asthma attack following dust storms, and respiratory and ocular problems caused by exposure to ash and smoke from volcanoes and wildfires. Climate extremes can cause hypothermia or heat-related illness. Asthma and allergic problems including rhinitis, dermatitis, and conjunctivitis have been reported as consequences of human-made disasters such as oil spills.
In addition to acute illnesses, chronic problems also have been reported as consequences of disasters: a well-studied example is the thyroid cancer and leukemia in children resulting from the Chernobyl nuclear accident. Moreover, long-term disabilities from severe physical injuries are also consequences of both natural and human-made disasters.
Stress caused by disasters is a risk factor for some chronic diseases. People with heart disease, hypertension, and diabetes are at risk of higher morbidity and/or mortality after natural disasters. Increased risk of hospitalization for heart disease was also observed following the World Trade Center disaster.
Disasters can potentially increase the risk of communicable diseases, particularly in developing countries. This happens because of damage to sanitation services, poor hygiene, overcrowding in shelters, exposure to extreme weather conditions, damage to the health sector, and difficult access to the health facilities. However, the occurrence of outbreaks after natural disasters has been relatively rare. The association of dead bodies and outbreaks is also a myth. In fact, occurrences of outbreaks after disasters depend on the existence of the disease in the community before the event. Nevertheless, complex emergencies accompanied by large population displacement in chaotic situations and a lack of public health infrastructure have the potential for outbreaks to occur.
Disasters can provoke specific emotional reactions that take on a variety of different psychological responses, affecting both the primary victims (those directly involved in the disaster) and the secondary victims (such as relatives, coworkers, and schoolmates). In addition, relief workers can also experience mental health issues. The mental health ramifications are possibly greater for those who witness or are involved with certain experiences from a disaster. Some examples include loss of loved ones, life-threatening danger or physical harm, exposure to gruesome death, extreme environmental or human violence, and the loss of a home.
Direct Effect on the Health Care System
Health facilities and their personnel may become victims of disasters when their services are in highest demand. , It is important to preserve the ability of the health care system to continue its essential functions after disasters.
Disasters are capable of damaging the physical components and functions of hospitals, clinics, and primary health care centers. , Although structural damage significantly affects the health system, many health facilities fail to continue their operations because of damage to nonstructural components, such as electricity, water, heating and ventilation systems, and medical equipment. , , Overload of hospitals with trauma cases can also hinder appropriate service delivery.
Similar to the general population, health personnel can be killed or injured during disasters. In addition, acute illnesses, such as respiratory problems following dust storms, may lead to absence from work. Moreover, health personnel might not be able to report to work because of the severe weather conditions, destruction of roads, transportation stoppage, or security concerns around a disaster. Disruption of the medical staff hinders the functions of a health care system during disasters.
Indirect Effect on the Health of the Population
Indirect effects of disasters on a population’s health are associated with disruption of normal societal functions, living conditions, and routine health care. Disasters cause damage to neighborhoods, homes, and property and thus often expose the affected population to stressors related to living in temporary settlements. The death of family members and friends causes additional stress. Further, disasters may change or destroy the social network and support systems that existed before the event. Damage to the economy and livelihoods has adverse effects on society, families, and individuals, as well as the quality of life of the survivors. The recovery of those affected depends on the community resilience and the assistance they may receive. Vulnerable people, such as the elderly, disabled, and those with low socioeconomic status, are at higher risk of late or incomplete recovery.
Destruction or overload of the health facilities beyond their surge capacities adversely affects the health of populations. In addition, inadequate preparedness by providers and patients for disastrous situations increases the adverse effects of disasters. These conditions hinder delivery of primary health services, such as vaccination, maternal and childcare, and management of chronic diseases: for instance, increased hospitalization rates were observed among dialysis patients following Hurricane Katrina because of disruption of planned care.
Other examples of indirect disaster effects on a population’s overall health include problems with contaminated water from damage to water pipelines, malnutrition and famine because of damage to agriculture, and food insecurity following droughts or complex emergencies. Further, carbon monoxide poisoning caused by fuel-burning equipment and toxicity from gasoline exposure were reported following Hurricane Sandy. ,
Indirect Effect on the Health Care System
Even when a health facility is not directly affected by a disaster, damage to other infrastructure systems hampers its functionality. The systems that are essential to the operations of health facilities include roads and transportation, water supply, electrical power, telecommunications, natural gas, and steam energy. Further, interdependencies among the infrastructure systems should be considered because systems do not operate in isolation of one another. For instance, telecommunications depends on electricity. Health facilities are among the most dependent systems on other infrastructures, so their functions are affected by damage to other systems.