William H. McNeill, ‘Plagues and Peoples', March 1997:
“….The climate of medical opinion has changed considerably since this book came out, for in 1976 many doctors believed that infectious diseases had lost their power to affect human lives seriously. Scientific medicine, they supposed, had finally won decisive victory over disease germs. Newly discovered antibiotics and relatively simple prophylactic and public health measures had at last made infections easy to prevent and cure. The World Health Organization actually succeeded in eliminating smallpox from the face of the earth in the same year this book was published, and optimists believed that other infections, like measles, might go the same way if sufficient medical effort were put into worldwide campaigns to isolate and cure each and every infection.
A glance at my concluding remarks on this page will show that I did not accept this view of what doctors had accomplished, and it is now clear that the elimination of smallpox in 1976 was the high point of the World Health Organization’s remarkably successful post-World War II campaign to reduce human deaths from infections. Thereafter, infectious organisms launched a counteroffensive. The appearance of AIDS was the first notable landmark of this process; and despite initial expectations, the subsequent identification of the HIV-1 virus that causes AIDS has not yet led to a cure.
Development of resistant strains of malaria, TB, and other familiar infections was a second, and in many ways more important, sign that twentieth-century victories over the parasitic microorganisms that feed upon our bodies was only an unusually dramatic and drastic disturbance of the age-old balance between human hosts and disease organisms. As the century comes to its close, it seems sure that infections are coming back, regaining some of their old importance for human life; and medical men have begun to recognize how their increasingly powerful interventions had the unexpected effect of accelerating the biological evolution of disease germs, making them impervious to one after another form of chemical attack…
…The apparent conquest of infectious diseases between 1884, when Robert Koch first identified the cholera bacillus, and 1976, when WHO succeeded in eliminating smallpox, was assuredly one of the most drastic disturbances of older ecological balances ever achieved by human beings. Nonetheless, the way infectious diseases have begun to come back shows that we remain caught in the web of life—permanently and irretrievably—no matter how clever we are at altering what we do not like, or how successful we become at displacing other species.
This book explores one important aspect of our extraordinary capability for altering natural balances, and the limitations of those capabilities. Nothing that has happened since it was written contradicts its general thrust. We remain part of the earth’s ecosystem, and participate in the food chain whereby we kill and eat various plants and animals, while our bodies provide a fair field full of food for a great variety of parasites. No conceivable change in the earth’s ecosystem will alter that fundamental condition of human life, even though changes in our knowledge and behavior can and will continue to alter the incidence of disease and the array of what we eat….”
