Jonathan Kennedy Tells the World's History through Eight Plagues

Most accounts of humanity’s origins, and our evolution since, have understandably put Homo sapiens center stage. It was our ingenuity, our tools, our cultural savvy that enabled our species to survive long past others—that allowed wars to be won, religions to blossom, and empires to rise and expand while others crumbled and fell. But despite what the schoolbooks tell us, humans might not be the main protagonists in our own history. As Jonathan Kennedy argues in his new book, Pathogenesis: A History of the World in Eight Plagues, the microscopic agents behind our deadliest infectious diseases should be taking center stage instead. Germs and pestilence—and not merely the people who bore them—have shaped inflection point after inflection point in our species’ timeline, from our first major successful foray out of Africa to the rise of Christianity, to even the United States’ bloody bid for independence.

Three years after the outbreak of a devastating infectious disease with a staggering death toll, spending time with a book that vividly details the microbial richness of human history might not rank high on most people’s must-do lists. But those with enough of an epidemiological appetite to pick up Kennedy’s new book will be gratifyingly—if not necessarily cheerfully—rewarded with the knowledge that their read was at least well timed. Epidemics, Kennedy reminds us, are not aberrations in our overstuffed, interconnected, climate-change-fractured world. And when the next one arrives, as it surely will, our response to it will be better if we remember, and avoid, the many mistakes of the past.

Kennedy’s book isn’t meant as revisionism; the broad strokes of history remain intact. But it gently sidelines humans—and, in doing so, humbles them. In the grand scheme of things, he writes, we have far less influence over the fate of our own species than we might like to think: “Very often we don’t make history in circumstances of our own choosing, but in circumstances created by microbes.” Humans aren’t alone, even in their own tale. We’re constantly being puppeteered by our viral, bacterial, and parasitic passengers—simply riding a narrative arc that’s been constantly bent by our bugs.

Consider, for instance, the vanishing of the Neanderthals, one of the early human species that lived alongside and interbred with ours. Neanderthals were once perceived as brutish and dumb—intellectual inferiors who whimpered out after our ultra-brainy species spread over the globe. Decades of scientific findings now exist to refute that notion, showing that Neanderthals were extraordinarily sophisticated—painting caves, lighting fires, even making use of medicinal plants. What snuffed them out wasn’t their lack of smarts but a lack of immunity to the (likely viral) diseases that Homo sapiens introduced to them as the two species mingled.

That same tragic motif plays out repeatedly over some 60,000 years, as Kennedy points to the cast of microbes that played startlingly prominent roles in several otherwise-familiar chapters of our history. Neolithic farmers may have edged out their hunter-gatherer predecessors with the help of hepatitis B, tuberculosis, measles, and a bevy of mosquito-borne viruses; diseases such as typhus and smallpox may have helped turn the tide against Athens in the Peloponnesian War. Spanish conquistadors appear to have been aided in their obliteration of the native populations by smallpox—an inadvertent weapon at least as powerful as any tool forged by hand. And although it’s clear that various sociopolitical factors were key to the ultimate founding of the United States, it’s also a bit fun to cheekily consider malaria-carrying mosquitoes as among the “founding mothers of the United States,” as the historian John McNeill once put it. The parasitic disease—which established itself in the American South prior to the Revolution—killed eight times more British troops than did American guns, potentially enough to substantially tilt the odds.