Scientists find traces of 4,000-year-old virus in manuscripts

Scientists have discovered DNA of sheep pox virus on the pages of medieval manuscripts and parchments from European libraries. Among the 17 infected leaves are pages from the York Gospels (990–1020 AD) and a Latin glossary from around 800 AD. Analysis of 754 samples revealed 21 new poxvirus genomes, the oldest dating to the Bronze Age (1875–1645 BC).

Scientists analyzed 754 samples from European libraries and archives, including archaeological bones and ancient documents, and discovered DNA of sheep pox virus on the pages of medieval manuscripts. Among the 17 infected leaves were pages from the thousand-year-old York Gospels, created in Canterbury between 990 and 1020 AD, a Latin glossary from around 800 AD, and copies of the Epistles of Paul the Apostle. Restorers carefully erased the surface of the parchment with an eraser, and the resulting dust was sent for DNA analysis. As a result, researchers obtained 21 new poxvirus genomes, now considered the oldest known representatives of this family. Of the 17 infected leaves, only 3 were made from sheepskin, 10 were calfskin, and 4 were goatskin. The earliest traces of the pathogen were found in animal teeth from a Bronze Age settlement of Myrzhik in Kazakhstan (1875–1645 BC) and finds from the Altai region. Comparative analysis showed that nine genes, inactive in modern strains, were already non-functional in ancient samples from Kazakhstan, indicating the completion of a key evolutionary adaptation of the pathogen to sheep hosts about 4,000 years ago. The study was published in Science Advances.