Globalization & Public Health Research
BY KATHRYN H. JACOBSEN
In 2003 several individuals who ate at a chain restaurant near Pittsburgh died from hepatitis A virus. The outbreak was eventually linked to green onions imported from Mexico. Oddly enough, people who live in the United States are in some ways at greater risk of death from hepatitis A than populations in most other countries simply because most of us have not been exposed to the infection during childhood, when the symptoms of the disease tend to be milder. For one of my research projects, I developed mathematical models that predict how hepatitis A risks are likely to increase in populations around the world in coming years. Other epidemiologists are developing models for a variety of other diseases in the hope of contributing to improving health both close to home and around the world.
Regardless of our cultural, social, economic and other differences, all people know what it is like to be sick, to care for an ill or injured family member or friend, and to mourn the loss of a loved one. Because of those universal experiences we have compassion for those whose health is more precarious than our own. More than 70 percent of the 10 million children under the age of five who die each year succumb to preventable and treatable conditions such as pneumonia, diarrhea, malaria, and measles. Malnutrition contributes to about half of these deaths. Millions of people around the world do not have access to even basic levels of health care because of where they were born, how much their families earn, or a whole host of other circumstances that are often beyond their control. Our common humanity requires us to urgently seek ways to drastically reduce the world-wide number of preventable deaths. Global health research is essential for developing and testing new methods for improving health and health care. It also plays a key role in tracking infectious disease outbreaks and preventing them from spreading.
EMERGING INFECTIOUS DISEASES
The field of global health combines traditional concerns about the health of people living in low-income regions – infectious diseases, poor nutrition, environmental hazards, child health, and pregnancy risks – with a growing awareness that infectious diseases do not recognize national borders. An outbreak anywhere in the world can quickly become an international crisis.
Modern transportation allows for a new infectious agent that emerges in any part of the world to be transported by aircraft to any other part of the world within hours. The original case of SARS (severe acute respiratory syndrome), which emerged in 2003, was probably acquired in an animal market. The infection was then transmitted from person to person across parts of Asia, and within months cases were found in Canada, the United States, South Africa, Brazil, and many European nations. If a strain of highly pathogenic avian influenza develops the ability to spread easily from human to human, an even faster and more widespread dissemination of the infection across the globe is expected.
Globalization is creating new infectious disease risks as economic development and integration leads to changes in land use patterns, human behavior, and human demographics. Urbanization increases the number of people that one contagious person is likely to infect. Alterations of the natural environment create new habitats for disease vectors such as mosquitoes. Even the advances in medical technology that allow us to treat and cure diseases that used to be fatal can contribute to the emergence of dangerous new strains of infectious agents that do not respond to current antibiotic therapies, such as MDR-TB (multidrug-resistant tuberculosis) and MRSA (methicillin-resistant Staphylococcus aureus).
In today’s interconnected world, our individual health and well-being is inseparable from everyone else’s. Personal health practices such as eating nutritious food, exercising, frequent hand-washing, and getting vaccinated might help keep you, your family, your neighbors, and your colleagues healthy. But we cannot prevent the birds that may carry influenza, West Nile virus, and other infectious agents from flying over our national borders or being carried to new locations by ships or planes, nor is it feasible to inspect every imported banana or lettuce leaf for possible contaminants. The complexities of the spread of disease require us all to think beyond our households and communities to regional, national and global levels.
HEALTH AND SECURITY
The general public is now aware of threats such as influenza pandemics and possible acts of bioterrorism that demand the coordination of public health planning and emergency response by many nations. Dramatic portrayals in the movies and on TV that show how quickly societies might descend into chaos if faced with a widespread epidemic or if a new exotic disease emerges have alerted us to the prospect that any major outbreak might lead to increased conflict and insecurity.
The AIDS pandemic provides a drastic example of just how significantly disease can impact a population. HIV/AIDS has changed the entire social structure in some parts of sub-Saharan Africa. Because nearly all infections and deaths occur in young- and middle-aged adults (ages 15 to 49), older adults have been forced to take on the care of their sick adult children and young grandchildren. If the grandparents are deceased or unable to care for children, AIDS orphans may end up homeless and living on the street.
But it is not only the dramatic, news-making cases that affect security. The unremitting cycle of disease and poverty – in which a poor person is at increased risk of illness, and any illness creates greater economic hardship – also leads to vulnerability. It is not just infectious diseases that contribute to this cycle of poverty. A growing number of chronic conditions such as heart disease, stroke, diabetes, various types of cancer, mental health disorders, injuries, and disabilities affect people living in low income areas.
Globalization is introducing new chronic diseases into developing nations. “Lifestyle diseases” related to obesity, physical inactivity, and increased tobacco and alcohol use are now found even in countries where the burden of infectious diseases remains high. This means that rather than experiencing a health transition – which historically occurred when economic development shifted a population’s health profile from one characterized by high fertility, short life expectancy, and deaths from infectious diseases and undernutrition to a profile characterized by low fertility, long life expectancy, and deaths from non-communicable diseases – these countries are simultaneously burdened by infectious and chronic diseases.
This dual burden will become even heavier as the global population ages. The number of people aged 60 and over worldwide is expected to increase from 600 million in 2000 to 1.2 billion in 2025 and 2 billion in 2050. More than two-thirds of older adults live in the developing world, and this is expected to increase to 75 percent by 2025. In addition to the costs of health care associated with treating long-term conditions, an increase in chronic disease prevalence can lead to decreased economic growth and productivity, and, potentially, an increased risk of political instability.
Public health professionals and other experts in global health are searching for ways to address these challenges. One of my current projects compares the protocols used by epidemiologists to gather health information from people living in various world regions. It is essential that epidemiologists understand local cultural and research practices. This information will help public health professionals to work together to study diverse populations, to strengthen international communication networks, and to build trust with other health professionals and with the communities in which we work.
Meanwhile, all of us – whether health professionals or not – make decisions on a daily basis that, at least peripherally, have an effect on human and environmental health both close to home and, potentially, in the far corners of the globe. Educated and informed citizens can respond to globalization by advocating for the health of others around the world, protecting our own health, and responding responsibly to new disease threats and safety hazards.
Kathryn H. Jacobsen (kjacobse@gmu.edu) is an assistant professor of epidemiology in the department of Global & Community Health in the College of Health and Human Services (http://www.gmu.edu/depts/chhs/gch) and is the author of Introduction to Global Health (Jones & Bartlett Publishers, 2008).
