Pathogenesis

In the age of COVID-19, it is impossible not to appreciate how a virus can upend societies, reshape politics and divide populations. But what many of us do not know, and what Pathogenesis: A History of the World in Eight Plagues makes clear, is that viruses and bacteria have been integral to all of human history—including the emergence of Homo sapiens as the sole surviving human species on the planet. In his debut book, public health scholar Jonathan Kennedy explains the complex interplay of humans, germs and animals, and the consequences of those interactions.

Most of us know about the carnage of the Black Death and the devastating impact smallpox had on Indigenous populations. But there have been many other plagues, and the ways their combined effects helped create the modern world make for compelling reading. For example, Kennedy tells how the bubonic plague was a significant factor in creating a new European economy, which in turn influenced the colonization of the Americas. That colonization resulted in not only the decimation of Native populations but also the introduction of enslaved West Africans to take Native Americans’ place as forced laborers—as well as the introduction of the viruses that cause yellow fever and malaria. These diseases contributed to the liberation of Haiti from colonial rule, as well as the economic conditions that supported chattel slavery and its attendant horrors in the Southern American colonies. These forces in turn gave rise to other deadly epidemics that had their own repercussions, and on and on.

Kennedy is not arguing that germs were the sole contributors to these and other historical events; economic, sociological and political factors also played their roles. But Pathogenesis makes a convincing case that germs did help mold history—and that history in turn affected how germs evolved and traveled around the globe with ferocious efficacy. Kennedy’s final chapters are cautionary but not pessimistic. What has happened in the past can happen again—but not necessarily in the same way. With this knowledge, perhaps we can be better armed when, not if, the next plague emerges.