Researchers have mapped a comprehensive catalogue of infectious diseases that affected prehistoric populations and continue to circulate today. The study, published in Nature, analyzed ancient DNA from bones and teeth of 1,313 individuals across Eurasia, dating from the Early Stone Age (about 12,500 years ago) to around 200 years ago. Seven of these samples are even older, with the oldest dating back 37,000 years.
The research provides new insights into zoonoses—diseases transmitted from animals to humans—such as plague, leprosy, and yersinosis. The findings indicate that many zoonotic diseases began appearing around 6,500 years ago. This period aligns with when humans started living closely with domesticated animals.
Astrid Iversen, Professor of Virology and Immunology at University of Oxford’s Nuffield Department of Clinical Neurosciences and co-author of the study, said: "Before 6,500 years ago, we only found DNA from one pathogenic microorganism in the samples from Eurasia, which we could classify as a zoonosis. After that time, zoonoses, to some extent, start causing people to die, and about 5,000 years ago, zoonoses really took off, according to our analyses of ancient human remains."
The increase in zoonotic disease incidence about 5,000 years ago coincides with migration patterns into north-western Europe from the Pontic Steppe region—present-day Ukraine, south-western Russia and western Kazakhstan.
Professor Iversen further explained: "Zoonoses first became a major problem for humans when we started keeping animals together in large herds and living close to these animals - eating their meat and drinking their milk. This meant that the animals could more easily infect each other, and that the risk of them infecting humans increased."
Today about 70 percent of newly discovered infectious diseases are zoonotic in origin. Examples include salmonella and listeriosis as well as Yersinia enterocolitica (causing gastrointestinal infection), Borrelia recurrentis (louse-borne relapsing fever), rabies and MRSA.
The research was led by Eske Willerslev at the University of Copenhagen’s Lundbeck Foundation GeoGenetics Centre and at the University of Cambridge. Willerslev stated: "In addition to providing information on historical conditions related to infectious diseases, the mapping also provides a deeper understanding of a number of these diseases that can still affect humans today. For example you can see how some of the pathogenic microorganisms have genetically changed over time."
The full paper is available in Nature under the title ‘The spatiotemporal distribution of human pathogens in ancient Eurasia and the emergence of zoonotic diseases’.