Parchment Clues Pinpoint 3,500 Years of Sheeppox Virus Evolution

Researchers extracted DNA from animal skins used to make medieval books and found 21 sheeppox virus genomes dating from about 1700 BCE to 1917 CE, enabling reconstruction of over 3,500 years of the virus’s evolution. The DNA was recovered non-invasively by erasing parchment surfaces, suggesting archives can preserve ancient pathogen DNA and reveal past outbreaks. The study places the virus’s divergence in the Bronze Age (around 3000 BCE) and notes some genomes may reflect cross-species infections or parchment contamination, but overall the sheeppox genome has remained fairly stable, offering insights for future disease control.