State of the World 2005 Trends and Facts - Containing Infectious Disease

... the biggest source of human insecurity, past and present, is the dreaded Fourth Horseman of the Apocalypse—infectious disease.”

fig 3-3 When measured by premature deaths and associated physical suffering, the greatest threat to human security is infectious disease. All of the wars of the twentieth century are estimated to have resulted in the deaths of an average of 1.1 million combatants and civilians per year. But at present, communicable diseases are killing fourteen times that number of people annually. Advances in medical research have led health officials to repeatedly claim victory in the campaign against infectious disease; yet over the last three decades, old maladies such as tuberculosis, malaria, and cholera have spread geographically and more than thirty previously unrecognized diseases such as Ebola, HIV, Hantavirus, and SARS have emerged as new threats to human well-being.

Why, after repeated declarations that the struggle against infectious disease was over, are experts now much more wary about the challenges presented by pathogenic microorganisms? Not only is the campaign to eradicate infectious disease an ongoing one, but pathogens have exhibited remarkable resilience and flexibility. And the acceleration of international travel and the growth of global commerce are making the rapid spread of infectious diseases a much more pressing security challenge. Yet although pathogens have claimed large numbers of human casualties, relatively few resources from public treasuries have been devoted to dealing with them, as the causes of and remedies for infectious diseases have remained poorly understood.

The Fourth Great Wave

“Occasionally, ... virulent and debilitating pathogens emerge for which immune systems have few defenses, and fatal diseases can then move quickly through human populations.”

Large-scale disease outbreaks, epidemics, and even pandemics occur when something happens to disturb an evolutionary equilibrium that normally exists between people and pathogens. Disequilibrium can result from changes in human behavior or circumstances, mutations in or movement of pathogens, or changes in shared environments, such as occurs with international travel. By the same token, reasonably benign viruses and bacteria can mutate into more destructive serotypes. And previously unknown pathogens can jump from animals to people, as is the case with avian flu today. Finally, environmental changes such as a warming climate can upset established equilibriums between people and pathogens, facilitating new disease outbreaks.

In at least three periods in history, significant changes in relationships between people and microbes have facilitated disease outbreaks or even epidemics. The first wave began about 10,000 years ago, when the domestication of wild animals during the early stages of the Agricultural Revolution brought people and animals closer together, providing more opportunity for disease organisms to move between them. The second wave began about 2,500 years ago as increasing contact among centers of civilization, such as the Roman Empire in the West and the Han Dynasty in the East, accelerated the spread of diseases among previously unexposed peoples. And the third wave began during the era of transoceanic exploration and trade expansion of the fourteenth and fifteenth centuries, when the bubonic plague arrived in Europe from Asia, and European explorers and settlers brought smallpox, measles, influenza, and other diseases to indigenous populations across the western hemisphere.

Today, there is considerable evidence that a fourth wave is building due to the dynamics of industrialization, globalization, population growth, and urbanization. The slow-moving HIV/AIDS pandemic already has killed more than 20 million people and sickened between 34 million and 46 million. Additionally, there is deep concern among health officials that an influenza virus, perhaps a communicable and lethal variant of the avian flu that has swept through Europe and Asia, could spread rapidly around the world leading to millions of human casualties before an effective vaccine could be developed. So despite all of the recent advances in medical care, “microsecurity”—freedom from various adverse health effects of microbial-scale agents—once again seems to be diminishing as new changes take place in people, pathogens, and their shared environments.

The Dynamics of Disease Outbreaks

“Today, the most obvious among destabilizing factors are changes in human circumstances and behavior.”

Demographic shifts, including population growth, rapid urbanization, and increasing migration, are now major contributors to insecurity—as well as to disease. As more people live in unsanitary conditions in more densely packed cities, it is easier for pathogens to spread rapidly. Population growth is also pressing people to settle on previously unoccupied land, often cleared forests, that is frequently shared with numerous potentially dangerous pathogens. Similarly, crowded refugee camps are ideal incubators for diseases, and the people who do get to leave them often bring diseases along to their new locations.

Persistent poverty is another factor increasing the potential for disease outbreaks, as the gaps between rich and poor both among and within countries increase. We live in an epidemiologically divided world: many people suffer from infectious diseases of the underfed at the same time that an increasing number are afflicted with chronic diseases of the overfed. Yet people living in highly impoverished conditions have little access to medical care. And the diseases that most commonly affect the poor attract scant research and development spending.

The Epidemiologic Divide

  • In Africa, infectious and parasitic diseases account for about half of all deaths, while in Europe they account for only two percent.
  • Each year more than 2.3 million people, primarily in poor countries, die from eight diseases that could easily be prevented by vaccinations.
  • Low- and middle-income countries carry more than 90 percent of the world’s disease burden but account for only 11 percent of health spending.
  • In the United States, total per capita health expenditures stood at $4,887 in 2001, compared with $6 in Niger, $7 in Sierra Leone, and $15 in Nigeria (at the average U.S. dollar exchange rate).
  • Between 1975 and 1997, only 13 out of the 1,233 drugs that reached the global market were applicable to the tropical diseases that are responsible for the greatest number of deaths from infectious disease.

Changes in the ways that people behave (or misbehave) are also among the factors upsetting the balance between people and pathogens. Ecologically unsound practices, such as grinding up dead animal parts to feed to living ones, can only improve the position of pathogens. Changing patterns of sexual behavior, including unprotected sex with multiple partners, have dramatically increased the incidence of sexually transmitted diseases such as herpes, syphilis, and gonorrhea. And intravenous drug use accompanied by needle sharing has greatly accelerated the spread of hepatitis, HIV/AIDS, and other diseases.

Meanwhile, technology is transforming the nature of the environment in which people and pathogens interact. The growing speed and pervasiveness of international travel means that more people, produce, and pathogens are moving swiftly across borders. Technology has also spurred environmental changes that are helping new diseases emerge and old ones resurface and spread. With climate change, for example, serious diseases such as cholera, malaria, and yellow fever could spread to presently temperate areas as warming takes place. And paradoxically, antibiotics and other pharmaceuticals that are intended to control pathogens often rebound with detrimental effects—including creating families of drug-resistant microbes.

The Current State of “Microsecurity”

As these and many other factors significantly change relationships among people and pathogens, it is clear why the campaign against infectious diseases is far from over. Over the last three decades, 20 previously well-known diseases have reemerged or spread geographically and at least 30 diseases not previously known to be infectious have been identified. Unfortunately, accurately assessing the current state of biosecurity in various regions of the world is a complex undertaking.

In 2002, an estimated 57 million people died of all causes worldwide. The bulk of these deaths, 33.5 million, were due to noncommunicable and chronic diseases, including cardiovascular disease, cancer, noninfectious respiratory diseases, and digestive diseases.

The remaining 18.3 million deaths were caused by maternal and perinatal conditions, nutritional deficiencies, and communicable diseases—with the foremost among these being respiratory infections like influenza and pneumonia, HIV/AIDS, diarrhea, tuberculosis, and malaria. Most of these deaths were avoidable and thus are appropriate security concerns.

Looking to the near future, the most pressing issue will remain HIV/AIDS. Between 34 million and 46 million people are now living with HIV/AIDS worldwide, and there have been more than 20 million HIV/AIDS fatalities to date. India, China, Nigeria, Ethiopia, and Russia are likely to see a rapid growth in HIV/AIDS over the next few years, according to the CIA's National Intelligence Council. The most worrisome near-term threat from traditional disease, however, is posed by influenza, which periodically shifts to new, more deadly forms that may spread rapidly from person to person. The World Health Organization has estimated that, even under today’s conditions, a pandemic flu outbreak could kill 650,000 and hospitalize 2.3 million people in industrial countries alone.

Healthy Life Expectancy

In Japan, the healthy life expectancy (HALE)—the number of healthy years that a newborn can expect to live based on current rates of ill health and mortality—is 75, meaning that the average Japanese child born today can expect to experience 75 healthy years and 6.9 years of disability due to infectious or chronic diseases. In Sierra Leone, in stark contrast, a child born today has a healthy life expectancy of only 28.6 years.

People in Japan, Sweden, and Switzerland can count on at least 73 years of healthy life, while the United States only ranks twenty-eighth, with a healthy life expectancy of 69.3 years. At the lower end of the distribution, seven sub-Saharan African countries have HALEs of less than 35 years, a result of both poverty and the rampage of HIV/AIDS.

Economic Consequences of Infectious Diseases

“It is obvious that history’s great epidemics and pandemics have had tremendous impacts on economic performance.”

In the fourteenth-century, the bubonic plague spread throughout much of Europe, devastating such a large portion of the population that it set the stage for the labor-saving innovations that shaped the Industrial Revolution. Today, contemporary disease outbreaks, such as the recent outbreak of SARS in Asia and the ongoing HIV/AIDS pandemic in Africa, are also having significant economic consequences.

The 2003 SARS outbreak had a devastating impact on East Asia, a densely populated and economically dynamic area. It took only a few weeks for the first SARS-related death to put the economies of China, Taiwan, and Singapore into a tailspin. In China, the tourism industry lost an estimated $7.6 billion and 2.8 million jobs. The loss to China’s overall travel economy in 2003 was thought to be around $20.4 billion.

Meanwhile, the HIV/AIDS pandemic has exacted enormous direct and indirect economic costs since it began its slow worldwide spread a quarter of a century ago. In developed countries, where HIV prevalence among adults generally is much less than 1 percent, the main economic impact has been on escalating health expenditures. But in many of the poorest countries most affected by the disease, HIV prevalence among working-age adults tops 20 percent. Sub-Saharan Africa is the area hit hardest: overall, growth in the gross domestic product of the 33 African countries that show a measurable economic impact from HIV/AIDS declined by an average of 1.1 percent a year between 1992 and 2002; by 2020, this will translate into a collective loss in economic growth of 18 percent—or roughly $144 billion.

Managing Future Disease Outbreaks

“The race continues between the growing ability of new and resurgent diseases to spread more rapidly and the ability of an increasingly sophisticated network of health officials and laboratories worldwide to respond quickly to new disease threats.”

Meeting the challenges of new and resurgent diseases in a more densely populated world requires the international community to take several important steps: increase surveillance to detect new disease outbreaks quickly, use anticipatory thinking and action to prepare for and avoid rapidly moving future pandemics, start a campaign to eradicate serious illness among the world’s poor, encourage much greater transparency in countries where disease outbreaks are likely to occur, and shift security spending away from military pursuits and toward building effective public health systems.

One of the most important issues in continuing efforts to contain HIV/AIDS and other infectious diseases in poor countries is the need to develop better mechanisms to distribute antiretroviral drugs and other pharmaceuticals to poverty-stricken disease victims. Advocates for victims who cannot afford treatments developed and priced in industrial countries disagree with intellectual property and profit concerns raised by pharmaceutical companies. And there is a related problem of training enough health care workers to administer these drugs and monitor the condition of patients, a problem made worse by the fact that health workers themselves are dying of AIDS in considerable numbers or emigrating.

The next stage in containing infectious diseases requires confronting difficult political and economic issues. Primary among these is redefining security funding priorities to reflect the serious nature of the challenges of new and resurgent diseases in an era of globalization. And as recent disease outbreaks have been accompanied by reluctance on the part of government officials to supply timely information, greater transparency is essential to cope with the threat of fast-moving viruses. Economic liability issues also must be addressed, arising from the need for rapid development of vaccines in the case of swiftly moving diseases. Finally, there is a pressing need to create innovative mechanisms to provide affordable drugs to disease victims in poor countries as well as incentives for the development of new vaccines and medicines applicable to the serious diseases that are still endemic there.

The good news is that HIV/AIDS, SARS, and the threat of bioterrorism have alerted policymakers to the serious human security issues posed by infectious disease. The first step in responding to the increasing disease threat has been to use enhanced telecommunications capabilities to create more effective surveillance networks and to apply new medical expertise and technologies to the task of rapidly identifying potentially lethal diseases. But much more remains to be done. The public health infrastructure must be substantially improved in almost all countries, rich and poor. Most important, however, security priorities and expenditures should be revised drastically to reflect the seriousness of the threat posed by infectious disease in an increasingly interconnected world.


Discussion Questions:

  1. How does the spread of infectious disease undermine global security? What priority should governments give to addressing the spread of infectious disease?
  2. Nearly 40 percent of the population of Western Europe perished during the Black Plague, which was spread by rats and fleas. Could such a scenario be repeated in modern times?
  3. What are the most effective ways of managing global infectious disease pandemics cooperatively?
  4. How can limiting environmental degradation help mitigate the spread of infectious disease?
  5. What are the links between demographics, economics, and the spread of infectious disease?

Further information as well as the references for this material is available in State of the World 2005.