Researchers from a major Nordic university have traced a possible link between the domestication of early animals by humans and the rise of widespread infectious diseases such as plague and typhoid. The team published their findings in a scientific research compilation focused on ancient DNA evidence.
Archaeological records have long suggested that the danger of pathogens moving from animals to people increased when nomadic hunter‑gatherer groups in Eurasia began forming large, stable settlements about 12,000 years ago.
Advances in DNA analysis in recent years have enabled scientists to test this theory more directly. A multinational team examined more than 405 billion DNA fragments collected from 1,313 ancient sites across Eurasia, searching for microbial genes preserved in the remains.
Early results indicate that a sizable share of the pathogens primitive herders encountered originated in animals or other external sources. A bacterium linked to plague and lice‑related relapsing fever appears in human remains for the first time roughly 6,000 years ago, aligning with the shift from foraging to farming life.
From that point forward, DNA from zoonotic microbes—those that jump from animals to humans—appears consistently in the analyzed samples.
Early pastoral communities on the Eurasian steppes may have held a notable advantage. Beyond secure access to meat and dairy, their bodies may have begun adapting to the new animal pathogens they faced as sedentary life took hold.
One of the study’s authors, a geogeneticist identified as Martin Sikora, stated that the work provides direct evidence of an epidemiological transition toward a higher burden of zoonotic disease following the emergence of farming in historical times.
Earlier archaeologists noted that birds and other animals frequently visited places where ancient people lived in the Paleolithic era, a pattern that may have influenced early exposure to animal pathogens.