This is not simply true of the Western tradition, but also true in China, where Buddhism took root in conservative, Confucian China after a plague wiped out nearly half of the population. And disease can also give rise to a lack of faith -- McNeill suggests that the 18th century Enlightenment was spawned partly because industrialization and urbanization created fetid cities with poor sanitation, which gave rise to epidemics that caused people to doubt the existence of a caring God. The discovery of the sources of diseases, like insects and rats, were undoubtedly a boon to mankind. Without the delousing of during World War I many soldiers would have caught communicable diseases from the pests, and knowledge of microbes enabled people to take precautions against the spread of illnesses throughout the 20th century, and our knowledge of how new illnesses are spread is never complete. In the developing world, the landscape continues to be shaped by disease. Today, long after McNeill wrote his book, this continues in Africa, with the AIDS epidemic, although, as he notes in his updated introduction, he does not believe that AIDS, compared to plagues of the past, is nearly as significant or as deadly as, for example, the bubonic plague in Europe.

Plagues continue to this day. Even during McNeill's first edition, the bubonic plague was still...

Epidemics of influenza occurred even within the 20th century in America. And high-speed air travel often facilitates rather than inhabits the spread of disease, as during the outbreak of Lassa fever chronicled in the later portions of the book devoted to outbreaks in the developing world.
At times, McNeill's assertions are so broad, and based upon scanty historical evidence and observation of non-scientific observers from ancient history; his book reads more like an essay than an argument substantiated with real medical or historical evidence. But regardless, his book is an interesting counterweight to histories that totally ignore the role of disease. On one hand the book's outreach is so broad, general, and one-sided, there is no way that it could offer a complete picture of both the expansion of Islam and the fall of the Roman empire, with influenza and Lassa fever outbreaks thrown in for good measure. But if nothing else it is an important reminder to follow the epidemiological trail when examining the causes of historical events, as well as tracing economic and political causes of demographic, ideological, and political shifts in history.

Works Cited

McNeill, William H. Plagues and People. Anchor Press, 1976.