Scientists Found Ancient Virus DNA in Books That Are Nearly 1,000 Years Old
You don’t often hear about sheep pox. According to Wikipedia, it’s “the most severe of all the animal pox diseases.” Luckily, it was eradicated from continental Europe in the 20th century, though it still pops up here and there; for example, a study published in Science Advances found sheep pox in DNA extracted from a medieval parchment.
Books back then were all bound by animal skins. Geneticists literally rubbed pencil erasers against ancient pages to lift genetic residue, showcasing how, in our wondrous age of science, minute DNA traces on ancient paper create not just a textual archive but a kind of biological one.
The guys who were scribbling down 1,000-year-old Gospels in books made of sheep, goats, and cows were inadvertently creating a permanent biological record of the entire pasture.
By pairing this codex residue with ancient sheep teeth from Bronze Age sites in Russia and Kazakhstan, the international research team reconstructed 21 ancient viral genomes spanning over 3,500 years. This new data pushes the sheep pox pathogen’s timeline back around 5,000 years, to when Eurasian humans began densely packing sheep together for wool shearing. It turns out that cramming a bunch of animals together creates a breeding ground for disease.
The researchers also found viral DNA on pages made of calfskin, goatskin, and paper, indicating possible cross-species contamination, or that medieval parchment makers used infected animal glue gelatin for binding.
Despite a history of brutal outbreaks that can wipe out up to 80% of a herd’s young, the sheep pox genome has remained remarkably stable over millennia. This genetic persistence is crucial today, as modern farmers, like those battling ongoing livestock outbreaks in Greece, face the same biological menace that medieval monks unwittingly included in their holy texts.
