Ancient virus DNA found in medieval texts

Researchers studying medieval manuscripts in Britain, continental Europe, and Russia discovered genetic traces of the sheep pox virus, a contagious and often fatal disease affecting livestock.

Scientists examined historic documents including the York Gospels and the Corpus Glossary, dating from the eighth to the fifteenth centuries, as well as teeth from Bronze Age settlements in Russia and Kazakhstan.

They found viral DNA not only in parchment made from sheepskin but also in materials made from goats, calves, and even paper, suggesting the virus spread between species or contaminated the parchment-making process. The team recovered ancient sheep pox virus genomes spanning from 1700 BCE to 1917 CE, revealing the virus has infected European livestock for at least 3,500 years, and possibly 3,700 years, based on finds in Kazakhstan.

By comparing ancient and modern viral DNA, the researchers mapped how different lineages of capripoxviruses evolved alongside human livestock management practices beginning around 11,500 years ago. The study demonstrates that the sheep pox virus genome has remained remarkably stable for millennia, which could aid future efforts to combat the disease.

This discovery is particularly timely given the current outbreak of sheep and goat pox in Greece, where farmers have been forced to destroy large numbers of animals to control the spread.