Epilogue

There will be more pandemics. A pandemic might come from an old, familiar foe such as influenza or might emerge from a new source—a zoonosis that makes its way into humans, perhaps. The epilogue asks how the world will confront pandemics in the future. It is likely that patterns established long ago will re-emerge. But how will new challenges, like climate change, affect future pandemics and our ability to respond? Will lessons learned from the past help with plans for the future? One thing is clear: in the face of a serious pandemic much of the developing world’s public health infrastructure will be woefully overburdened. This must be addressed.

7. HIV/AIDS

HIV/AIDS had been percolating in central Africa since the early twentieth century, but it appeared in its now recognizable form in the spring of 1981. Doctors in America spotted a strange increase in rare infections and Kaposi’s sarcoma, especially in sexually active gay men. In 1982, it was named acquired immune deficiency syndrome (AIDS). ‘HIV/AIDS’ explains that soon afterward the virus was identified as the human immunodeficiency virus (HIV), a complex retrovirus with several different identities. HIV makes its way into the body via infected fluids and can affect all members of society. There is no vaccine, but HIV/AIDS is now treatable, although access to drugs is uneven.

1. Plague

The plague is a disease caused by a bacillus, Yersinia pestis, transmitted by the bite of an infected flea. ‘Plague’ identifies three main periods of the pandemic. It first appeared in the sixth century ce with several epidemics in Europe and the Near East lasting until the end of the eight century. The second pandemic—the Black Death—began in 1347 and killed up to half of the continent’s population. The last European outbreak was in Russia in 1770. The third pandemic began in China in 1890 and spread rapidly around the Pacific world. Improved sanitation, isolation, and new antibiotics help, but the plague still exists today.

6. Influenza

The influenza that swept across the globe in three waves in 1918–1919 was the worst pandemic in history since the Black Death. Pandemic influenza had erupted before—most recently and severely in 1889–1892. But none approached the impact of the post–World War I pandemic, which killed at least fifty million people. ‘Influenza’ explains that more young adults and females were affected. Influenza can jump from animals to humans and back because it changes rapidly and often via antigenic drift. There were further pandemics in 1957, 1968, and 2009, and there will be more in the future. There is still much to learn about influenza.

5. Tuberculosis

Tuberculosis, caused by Mycobacterium tuberculosis, emerged in Africa about seventy thousand years ago. It accompanied modern humans on their migrations out of Africa, across the Indian Ocean, and then into Eurasia. Tuberculosis affects almost all parts of the body. Its most common and deadly form, carried in tiny droplets through the air from person to person and highly infectious, is pulmonary tuberculosis. It thrives in densely packed places. ‘Tuberculosis’ outlines the spread of the disease, early attempts to combat it, Robert Koch’s identification of Mycobacterium tuberculosis in 1882, the development of the BCG vaccine in 1908, the use of antibiotics, and the growing multi-drug-resistant TB problem.

Introduction

What are pandemics? The National Institutes of Health proposed pandemics must meet eight criteria: wide geographic extension, disease movement, high attack rates and explosiveness, minimal population immunity, novelty, infectiousness, contagiousness, and severity. The introduction explains that much of the way we confront pandemics now has been shaped by the past history of pandemic and epidemic disease. There is a clear relationship between disease and social conditions, conditions that do not exist everywhere and that will not be alleviated with biomedicine. The question of susceptibility—who gets a disease and why—is also important. Epidemics and pandemics cannot occur without a dense and mobile population.

4. Cholera

Cholera is caused by ingesting water contaminated with infected fecal matter. The disease spreads easily. Seven cholera pandemics have traveled the globe, the first starting in India in 1817. It was not until the 1830s that people began to see a link between poverty and cholera. During the 1854 London epidemic, John Snow, through his pioneering epidemiological work, realized the disease was waterborne. Then in 1883 Robert Koch discovered Vibrio cholerae in contaminated water. Since the 1960s, oral rehydration therapy has saved millions of lives, but cholera lives on, primarily in Africa, where lack of health infrastructure and poor sanitation allow it to thrive.

3. Malaria

Malaria originated in Africa and is caused by an infection with the plasmodium protozoan. Five types have infected humans; Plasmodium falciparum is the most lethal and is responsible for the vast majority of global malaria deaths. ‘Malaria’ outlines the spread of malaria from Africa, into Europe and the New World. Generally, agricultural and rural development has been responsible for the proliferation of malaria, but poor sanitation and stagnant water can make malaria an urban disease. Vector and parasite control is described, along with the World Health Organization’s Malaria Eradication Program and attempts to stem malaria with treated bed nets and more effective drugs.

2. Smallpox

The world was declared smallpox-free in 1980, but this endemic and pandemic disease had killed hundreds of millions of people over the preceding millennium. Smallpox was first described in fourth-century China, but the most deadly epidemics occurred from the early sixteenth century to the middle of the nineteenth century. ‘Smallpox’ considers how the disease became such a killer in the Americas, explaining virgin soil epidemics. It also describes the development of vaccination by Edward Jenner in the late eighteenth century, which was a success, but major epidemics continued to break out. Once enough people had been vaccinated, smallpox, with no non-human host, had no place to go.