Medieval Manuscripts Trace Over 3,700 Years of Virus History in Sheep

07:59

Ancient parchments do not only tell the story of human societies. They can also preserve the biological memory of the animals that provided their skins. An international team led by researchers from University College Dublin has exploited this feature to trace back several millennia in the history of ovine lumpy skin disease, a highly contagious viral illness affecting sheep.

Published on September 2, 2026, in Science Advances, the study relies on the analysis of hundreds of ancient samples from Eurasia. The scientists notably found fragments of viral DNA in medieval parchments as well as in archaeological remains of sheep.

Parchment as a Biological Archive

For centuries, books were made from animal skins. Sheep, goats, and calves provided the raw material for many manuscripts before the widespread adoption of paper.

These skins can preserve molecular traces of the animals to which they belonged. The researchers exploited this property to search for genetic remnants of the virus responsible for ovine lumpy skin disease.

The team studied over 750 samples, covering a period of nearly 14,000 years. In total, 39 ancient clues related to the virus were identified, and 21 new viral genomes were reconstructed.

Among the documents analyzed were the York Gospels, dated approximately to the year 1000, as well as the Corpus Glossary, a manuscript dating back to the 8th or 9th centuries and considered one of the oldest texts preserved in English.

A Technique That Preserves Manuscripts

This research also holds particular interest for heritage conservation. Scientists do not need to cut pages or damage documents to recover their biological material.

They can perform an extremely light sampling from the surface of the parchment using a clean eraser. The microscopic particles collected can then contain enough DNA and proteins for laboratory analyses.

This approach has been tested on the York Gospels. It opens a new possibility for studying ancient manuscripts while significantly limiting interventions that could alter them.

Infected Animals Behind Some Parchments

The presence of the virus on several pages made from sheep skins provides a particularly intriguing clue. It suggests that some of the animals used to produce these parchments were infected at the time their skins were prepared.

Traces were also found on goat and calf skins. However, researchers remain cautious about their interpretation.

These results could correspond to interspecies contamination, but another hypothesis exists: the skins may have been contaminated in workshops where different animal materials were simultaneously handled.

Genetic data alone do not definitively resolve between these different scenarios.

A History Dating Back to the Bronze Age

The medieval manuscripts represent only a fraction of the discoveries made by researchers. The oldest traces have been detected in sheep teeth from pastoral sites in the Eurasian steppe.

They date back to around 1,700 BCE, or more than 3,700 years. This discovery significantly pushes back the evidence of the circulation of ovine lumpy skin disease into the past.

The analysis thus allows tracking the evolution of the virus from Bronze Age pastoral societies to medieval Europe and the early modern period.

A Surprisingly Stable Virus Over Millennia

The comparison between ancient genomes and more recent viral sequences reveals another characteristic: the virus responsible for ovine lumpy skin disease appears to have evolved relatively slowly over a very long period.

Researchers have also identified traces of a now-extinct viral lineage that once circulated in Europe during the Middle Ages.

This discovery provides new insights into the history of animal diseases. It shows, above all, that the archives of the past are not only found in written texts: the materials used to create them can themselves preserve a biological memory spanning thousands of years.