(CN) — The Covid-19 virus is new to humanity, but pandemics are not. Nor is the probable evolutionary path of Covid-19 new, as a disease that jumped from animals to man. Evidence of such zoonotic plagues has been found in prehistory: more than 5,000 years ago in sites in China and Sweden.
Plagues have radically altered history far more severely than the 2020 coronavirus pandemic has altered our daily lives. They have contributed to the collapse of empires and economic systems, restructured geopolitics, forced mankind to invent new technologies, to end wars, and probably contributed to the spread of Christianity in Europe.
This series by Courthouse News will take a long view of plagues in history, drawing parallels to the havoc wrought by the novel coronavirus pandemic — social, economic, governmental, technological, legal and religious — to see what we have learned, or failed to learn, from more than 50 centuries of human suffering inflicted by microorganisms and their animal hosts.
Evidence of widespread adoption of agriculture and domestication of animals has been found as far back as 15,000 years ago. Barley, for example, a hardy grain, was being sown and harvested by 11,000 B.C. in Eurasia. The phenomenon of a food surplus allowed mankind to create cities and settle in them, where they lived more densely packed together, in close proximity to other mammals and the parasites they host.
That spurred an early “technology:” sleeping in closed quarters with domesticated animals in the winter, to benefit from their body heat, while defending them from animal predators and theft from human neighbors.
Indications of Yersenia pestis — the rat- and flea-borne bacillus that causes bubonic plague — have been found as far back as 3000 B.C. in a mass grave in Sweden. Mass graves at the Hamin Mangha archaeological site in Northeast China, dating from roughly the same time, appear to contain similar indications. The site contains 97 bodies in a small house that was burned down. Pottery and grinding instruments found with the bones indicate agriculture and settlement. A similar mass burial in Miaozigou, also in Northeast China, indicates an epidemic.
The Neolithic decline of around 3400 B.C., during which densely populated cities in Western Eurasia were permanently abandoned, may have been precipitated by plague, brought by humans living with animals and their parasites. An Oct. 22, 2015 paper in the scientific journal Cell reported that an international team of researchers extracted DNA from 5,000-year-old human remains in Sweden that is the closest ever to be identified as the genetic origin of Y. Pestis. It is believed to have diverged from other strains of plague about 5,700 years ago.
“The strain had the same genes that make the pneumonic plague deadly today and traces of it were also found in another individual at the same grave site — suggesting that the young woman did likely die of the disease,” according to a summary of the report published in Science News. The authors suggested that plague may have been spread by Neolithic traders, contributing to the decline of settlements as the Stone Age evolved into the Bronze Age.
Settlements of 10,000 and more people were becoming common in Europe, but were devastated around 5,000 years ago by massive human migrations from the Eurasian steppe. Previous researchers suggested that the invaders brought the plague with them, but the timing of the genetic origin indicates the European settlements were already starting to collapse, due to increased density of people, animals and food stored together and poor sanitation. “That’s the textbook example of what you need to evolve new pathogens,” the lead author Simon Rasmussen told Science News.
“Our results show that plague infection was endemic in the human populations of Eurasia at least 3,000 years before any historical recordings of pandemics,” Rasmussen et al. wrote in their own summary.