That ecosystem may, Kennedy argues, help explain longstanding mysteries, such as why Homo sapiens it survived the Neanderthals, for example; answer: a potent mix of pathogens and interbreeding. It may also make sense of how small groups of conquerors were able to dominate the huge New World empires: infectious diseases like smallpox were carried across the Atlantic by early arrivals, then decimated New World populations so that, in the moment of the conquests of Hernán Cortés. and Francisco Pizarro, once prosperous communities had already turned into ghost towns. “The population of the Americas fell by 90 percent in the century after Columbus landed on Hispaniola,” Kennedy says. “The population drop was so marked that it can still be seen in ice cores being drilled in Greenland. It had an impact on the temperature of the world.”
The success of the conquistadores has been attributed to guns, germs and steel, but it could also point to a quirk of fate: the New World has fewer domesticable animals than the Old, and fewer that live in large herds like cows and sheep. As a result, infectious diseases have been less likely to incubate and jump the species barrier to humans, so people living in the Americas have never had the opportunity to develop immunity to pathogens such as smallpox, which is believed to that jumped from cattle to humans. humans in the early days of agriculture, around 10,000 B.C.
There are other compelling examples of germs that changed the course of history: how the Black Death reduced the working population and increased the value of labor, bringing about the end of feudalism; how malaria made much of Africa impenetrable until the 1880s until the widespread use of quinine (which comes from the bark of the South American quina tree).
Diseases may also be responsible for the spread of religions such as Christianity, which exploded in popularity after the third-century Plague of Cyprian, which was, some scientists now believe, a type of hemorrhagic fever similar to Ebola. Christianity encouraged acts of kindness as a route to heaven: Instead of running from the sick, Christians nursed them back to health, drastically improving their survival rates. “Even with basic nursing, giving people food and water, you could maybe save two-thirds of the people who were sick,” Kennedy says. To the untrained eye this would have looked very much like a miracle, the best kind of publicity for any new religion. By comparison, “paganism didn’t provide a very useful way to interpret the impact of infectious disease outbreaks,” says Kennedy.
But the spread of Christianity also spread the notion of man’s dominance over nature. In the long run, that attitude has contributed to climate change and fueled our relentless drive into remote areas, both of which can spread new diseases as we rub against nature in strange new ways.
However, things came full circle with Covid. It remains to be seen what impact the latest pandemic will have. “Being in the eye of the storm is hard to say, but if we look back in history, there are so many cases of pandemics, epidemics that are coming, killing many people, damaging societies and creating the space for new ideas and new societies. . emerge,” says Kennedy. “Probably when we look back on this period, we will see that there were changes that were perhaps already underway, but Covid-19 accelerated them or changed the trajectory of history.”
Covid may have already served as a humble reminder of the natural order of things. “It’s been pretty shocking how many of us see the power of humans,” says Kennedy. “You can make a pretty good case that we have been living, and are still living, and will always live in the age of microbes. Coming to terms with that is part of really learning how to successfully live on this planet.”
(Pathogenesis: how germs made history by Jonathan Kennedy is published on April 13.)