The last pandemic was bad, but COVID-19 is only one of many infectious diseases that emerged since the turn of this century., I have found that these are primarily human factors: the ways we feed ourselves, the ways we live together, and the ways we treat one another. In a forthcoming book, “,” my colleagues and I examine how these same elements have influenced disease dynamics for thousands of years. Twenty-first century technologies have served only to magnify ancient challenges.
Farming itself was not the cause. Rather, it was the major lifestyle changes associated with this new enterprise. Agriculture supplied people withsocial hierarchies of newly agrarian societiesFor a dozen millennia, these patterns spread across the world like a plague of plagues. They persisted until the 19th and 20th centuries, when life expectancy rose with the precipitousthe discovery of effective antibiotics and most of the vaccines we use today.
These were significant reversals in the same ancient categories – subsistence, settlement and social organization – that led to the rise of infectious diseases in the first place. They resulted in humanity’s second epidemiological transition, a significant but only partial reversal of the changes that first began in the Neolithic period.
Most low-income countries experienced a later version of this transition after World War II, but their health gains from declining infections werethan those of their wealthier counterparts. At the same time, their losses to noninfectious diseases rose at comparable rates. These conflicting trends have led to a “worst-of-all-worlds” scenario with respect to the health of poor societies.