Key Takeaways
- Scientists extracted sheeppox DNA from medieval manuscripts to trace its evolution over 3,500 years.
- The virus has affected Eurasian sheep herds since at least the first century CE, with frequent outbreaks in the Middle Ages.
- Parchment from manuscripts acts as a 'biological time capsule', preserving genetic traces of ancient diseases.
Scientists have discovered that medieval manuscripts can serve as 'biological time capsules', preserving genetic traces of ancient diseases, including the sheeppox virus. This groundbreaking research, published in the journal Science Advances, reveals the virus has affected Eurasian sheep herds for at least 3,500 years.
The study, led by Louis L’Hôte, a graduate student at University College Dublin, involved extracting and sequencing sheeppox DNA from animal skins used for parchment in numerous medieval manuscripts. This method allowed researchers to trace the virus's evolution over time.
The earliest known written evidence of sheeppox infection dates back to the first century CE, with Roman accounts describing outbreaks of skin lesions in sheep. By the Middle Ages, there were more frequent mentions of deadly outbreaks, recorded in various agricultural texts and accounting documents in France, Spain, and England.
While there seemed to be a decline in outbreaks in 17th-century France, frequent outbreaks re-emerged in the 18th and 19th centuries, often with high mortality rates in the flocks. Great Britain did not experience a resurgence of sheeppox until 1847.
According to the study, these ancient genetic traces help us understand how pathogens evolved and impacted past societies. 'These genomes help us understand how these pathogens evolved and how they impacted past societies—such as sheeppox virus, which we show has been affecting Eurasian sheep herds for at least three and a half millennia,' said L’Hôte.
The findings suggest that archives and libraries around the world may contain the genetic traces of disease outbreaks in animals in the past. 'The recording of ancient DNA of pathogens has completely changed our understanding of infectious disease in the past, and here we show that parchment can also preserve animal pathogen DNA,' added L’Hôte.
This research not only sheds light on the historical impact of sheeppox but also opens up new avenues for studying ancient diseases. It highlights the potential of using non-traditional sources, such as medieval manuscripts, to understand the history of infectious diseases.
The recording of ancient DNA of pathogens has completely changed our understanding of infectious disease in the past, and here we show that parchment can also preserve animal pathogen DNA.
Louis L’Hôte, Graduate student at University College Dublin
