Medieval parchments reveal millennia-long history of contagious sheep pox virus

By gently rubbing the surface of medieval manuscripts, scientists recovered protein and DNA residues that contained the genome of the highly contagious sheep pox virus. The investigation examined more than 750 specimens, including parchment from the York Gospels and an 8th-9th century English glossary, as well as sheep teeth from archaeological sites on the Eurasian steppe. Researchers detected 39 ancient viral signatures and reconstructed 21 new viral genomes, spanning from Bronze Age herders to the dawn of modern Europe, and discovered a now-extinct medieval lineage.

Comparison with modern strains indicates the virus’s genetic makeup has remained relatively stable over millennia. The findings demonstrate that historical books, once used for human texts, also preserve hidden records of animal disease, offering a new source for studying past epidemics. Ongoing outbreaks of the disease in Europe, such as a recent epizootic in Greece, underscore the relevance of this archival approach.