The Stone Age was a naturally difficult time full of dangers. Besides ferocious predators, extreme weather conditions and the constant struggle for survival, a deadly threat lurked in the daily environment of human ancestors: infectious diseases.
Deadly Stone Age Microbes
A new study by scientists from Stockholm University and the Swedish Museum of Natural History sheds light on the disease-causing microbes that plagued Stone Age Scandinavia. By analyzing the microbiome of 38 individuals from hunter-gatherer communities and Neolithic agricultural settlementsthe researchers identified no less than 660 microbial speciessome of which were particularly prolific and potentially dangerous to human health.
Among these pathogenic microbes are Yersinia enterocolitica et Salmonella entericatwo bacteria well known for causing food poisoning. Ingesting undercooked meat or food contaminated with feces could then lead to serious or even fatal infections in a world lacking antibiotics and modern medical treatments.
The study also revealed the presence of Neisseria meningitisthe bacteria responsible for meningococcal diseasea potentially fatal disease. Although this bacteria can coexist harmlessly in the throat and nasal cavity of some people, it can cause serious complications, especially in individuals with weakened immune systems.
The potential role of social practices
One of the most striking findings of the study was the presence of Yersinia pestisthe bacteria responsible for the plague, in one of the individuals examined. Although plague is often considered one of the most fearsome pathologies in human history, researchers note that Foodborne illnesses were actually much more common at that time.
An intriguing aspect of the study is the highlighting of the potential role of social practices, such as close contact and kissingin the spread of infectious diseases. For example, we know that Neisseria meningitis is transmitted by close contact with people carrying the bacteria.
This new work gives us a fascinating insight into the health challenges faced by our Stone Age ancestors, highlighting the omnipresence of infectious diseases and their impact on prehistoric human populations.
Implications for human evolution
These findings highlight the profound impact of infectious diseases on the evolution of human populations. The constant fight against these pathogenic microbes would have played a key role in shaping the human immune system, favoring the selection of genes conferring increased resistance to certain infections. Furthermore, this research suggests that the emergence of complex social practices, such as grouping into agricultural communities and increased exchange between individuals, would also have influenced the dynamics of epidemics. These elements highlight the extent to which co-evolution between humans and microbes has contributed to defining the biological and social bases of modern societies.
Details of the study are published in Scientific Reports.
