Medieval manuscripts yield ancient sheeppox virus DNA, revealing livestock disease history

September 5, 2026 at 12:01 AM2 min

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Researchers recovered ancient sheeppox virus DNA from medieval parchment manuscripts dating from the 9th to 15th centuries. The findings indicate frequent sheeppox outbreaks among medieval European flocks and push the virus's divergence from related pathogens back to between 11,500 and 3,700 years ago. The study, published in Science Advances, also analyzed Bronze Age sheep teeth from Russia and Central Kazakhstan.

Key Facts

DNA from the sheeppox virus was found on parchment made from sheepskin, calfskin, and goatskin in medieval manuscripts.
The sheeppox virus diverged from goatpox and lumpy skin disease viruses between 11,500 and 3,700 years ago, coinciding with animal domestication in Europe.
The team recovered 21 ancient genomes from 1700 BCE to early modern Europe.
Bronze Age sheep teeth from settlement sites in Russia and Central Kazakhstan preserved DNA evidence of infection over thousands of years.

Parchment as Biological Archive

The team collected samples from medieval manuscripts housed at Yale University, Cambridge University, Corpus Christi College, University College Dublin, the Lambeth Palace Library, and Trinity College. Pages from a 15th-century Speculum Historiale, the 15th-century Clairvaux manuscripts, several 9th-century gospel text fragments, the 9th-century Achadeus Psalter, the early 11th-century Trinity Gospels, the Lambeth Bible, and the 1,000-year-old York Gospels were among the works sampled. Multiple pages, often from the same manuscript, contained DNA from the sheeppox pathogen, indicating infected animals were likely used to make the parchment. The presence of sheeppox virus DNA on calfskin and goatskin parchment suggests either cross-species infection or contamination during parchment production.

Ancient Genomes and Divergence

The team extracted DNA from Bronze Age sheep teeth collected at settlement sites in Russia and Central Kazakhstan, as teeth can preserve DNA evidence of infection over thousands of years. Comparison of ancient sequences with medieval ones showed the sheeppox virus diverged from goatpox and lumpy skin disease viruses between 11,500 and 3,700 years ago. This divergence coincides roughly with the domestication of animals in Europe. In total, the team recovered 21 ancient genomes from 1700 BCE to early modern Europe.