How Medieval Parchments Revealed the Origins of Sheep Pox

The skins of medieval manuscripts have yielded clues to a disease that once threatened the survival of entire flocks. An international research team extracted usable genetic material from parchment and used it to investigate the origins of sheep pox.

One source was the Cutbercht Gospel, believed to have been written in Salzburg around 790 and now held by the Austrian National Library. The researchers examined this and other parchments made from animal skins, recovering genetic traces that revealed information about the sheep used and the illnesses they carried.

Sheep pox was already regarded as a bad omen in ancient Rome. When small, fluid-filled pustules appeared on sheep, the highly contagious viral disease could spread through herds and destroy the livelihood of shepherds and farmers.

The disease remains notifiable in sheep and goats and is still found in Asia and Africa. Its actual age and the time when it first emerged had remained unclear. The genetic material preserved in the old parchment now offers a way to reconstruct that history.