Sikora, M., Canteri, E., Fernandez-Guerra, A. et al. (2023, preprint).
The landscape of ancient human pathogens in Eurasia from the Stone Age to historical times.
https://www.biorxiv.org/content/10.1101 ... 6.561165v1
"The Holocene saw significant changes in global lifestyles, with agriculture, husbandry, and pastoralism becoming key practices. These changes have long been hypothesised to have favoured the emergence and spread of infectious diseases in a so-called “first epidemiological transition”. In this study, we directly tested this hypothesis by carrying out the first large-scale characterization of the ancient pathogen landscape across Eurasia during the last ~12,500 years. Our results provide direct evidence of an epidemiological transition, with a first occurrence of zoonotic pathogens around 6,500 years ago, and consistent detection after 6,000 years ago [...] Although zoonotic cases also existed before the transition, the risk and extent of zoonotic pathogen transmission likely increased with the adoption of more widespread husbandry practices and pastoralism. Today, zoonoses are estimated to account for over 60% of newly emerging infectious diseases."
"Strikingly, some of the highest detection rates were seen around ~5,000 BP, a period which saw major demographic turnover in Europe due to the migrations of Steppe pastoralist populations. The observed association between zoonotic disease incidence and the CHG/EHG ancestry characteristic of those populations, but not with the LVN ancestry characteristic of the first agriculturists, indicates that the Neolithic to Bronze Age transition possibly played a pivotal role in the emergence and spread of zoonotic diseases in humans. It is possible that the Steppe pastoralists, through their long-term continuous exposure to animals, might have developed some immunity to certain zoonoses and that their dispersals carried these diseases westward and eastwards. Consequently, the genetic upheaval in Europe could have been facilitated by epidemic waves of zoonotic diseases sweeping through the continent. This may have caused significant population declines with depopulated areas repopulated by opportunistic settlers who intermixed with the remaining original population. Such a scenario would mirror the population decline of Indigenous people in the Americas following their exposure to Eurasian diseases introduced by European colonists."