Those who forget the plagues are condemned to repeat them


In the 1980s, when I was teaching biology at the University of California, Riverside (UCR), the world was grappling with the ever-expanding AIDS epidemic – and yet many people were still blissfully suffering from historical amnesia with regard to infectious disease. Among those who knew about sexually transmitted diseases other than AIDS, such as syphilis and herpes, very few understood much about the different kinds of parasites that caused them. For the most part, it was a commonly held belief that all diseases in the developed world had been eliminated by vaccines, or soon would be. After all, the average person had little if any direct experience with typhus, diphtheria, whooping cough, malaria, sleeping sickness or snail fever, and my students – at least those under the age of 25 – lacked a scar from the smallpox vaccine because the disease had been eradicated. People were also quick to take comfort in knowing they could rely on new drugs, such as antibiotics, to cure any new ailment that came along. They were convinced that our water was safe to drink and our food could be eaten with little fear of becoming ill. Most also felt sure that the transmitters of disease – mosquitoes, flies, lice and fleas – could easily be eliminated by insecticides. If by chance an individual did become infected, the assumption was that they could be treated quickly and effectively without any threat of the disease continuing to spread.

But most of the world is arguably delusional when it comes to infectious disease. As I wrote in “The Power of Plagues” (ASM Press, 2017), a book based upon an undergraduate course that I created and taught during my tenure at UCR, great plagues, such as the bubonic plague or smallpox or syphilis or influenza, can happen again. Plagues are natural and almost predictable phenomena. Although remarkable scientific advances have been made in controlling diseases through sanitation, chemotherapy, antisepsis, improved nutrition and immunization, we continue to live in evolutionary competition with microbes and there is no guarantee that we can always beat them at their own game. Lurking out there are germs and worms that may spread to our domestic animals, our domesticated plants, and us. These are the seeds of coming plagues.

While many factors lead to the emergence and spread of infectious disease, some of the most potent are human activities – social, economic, political, technological, environmental and behavioral – and, as we are now seeing in agonizing real time with the coronavirus, movement of people from place to place can be formidable. In the past, trade caravans, religious pilgrimages and troop movements, as well as colonization and slavery, shaped the location, nature and spread of many diseases including plague, cholera, typhus, smallpox, malaria, yellow fever and river blindness. Today, because of the unprecedented volume, speed and reach of travel, a potentially pathogenic parasite can be more easily introduced into a new geographic area by a “quick leap,” using high-speed trains, planes and ships. Pathogens that survive primarily or entirely in humans and are spread by sexual contact, droplet nuclei and close physical contact can be readily carried to any part of the world. For example, AIDS, TB, measles, pertussis, diphtheria, hepatitis – and now, the coronavirus – move as people move, and although some disease spread can be blunted by vaccination and “magic bullets,” there is never a complete halt.

The conquest of disease involves both medicine and social and moral factors, and the reverse is also true; that is, disease can influence the social, political and economic structure. What are we to do about this latest pandemic – and those that will most certainly continue to threaten our future as a species? Here, in a modified form (from public health authority Daniel M. Fox, PhD) are 10 generalizations on epidemic infectious disease:

1. Never underestimate the severity of the problem when an epidemic occurs.

2. Expect fear, anxiety, scapegoating and attempts to segregate and quarantine.

3. Enlist widespread support for a public health policy or program – include the medical, social and business communities and the government.

4. Even with an enlightened and powerful science, don’t expect a quick fix – it takes time, money and lots of scientific effort to develop “magic bullets” to control the spread of disease.

5. Education can contribute to the solution but it must be used in conjunction with other measures.

6. Voluntary public health programs work better than compulsory ones.

7. Recognize the importance of the cultural climate.

8. All diseases cannot completely be eradicated – we will have many more epidemics, but we should be optimistic that it may not require hundreds of years to have the effects of an epidemic disease blunted.

9. Learn the unique natural history of the disease – the nature of the agent and how it passes through a society.

10. Know that disease has influenced our history and it will continue to do so in our futures.

The question we are once again faced with is: How will the coronavirus plague impact our tomorrows?

Irwin W. Sherman is professor emeritus at the University of California.