A 3700‑year‑old virus emerged from the pages of a thousand‑year‑old book.

Scientists have made a surprising discovery in the animal‑skin pages of books that have survived from the Middle Ages to today. The virus DNA found in the roughly thousand‑year‑old parchment was determined to belong to the sheeppox virus that now causes outbreaks among sheep and goats. Older archaeological samples pushed the disease’s history back to about 3,700 years ago.

Thousand‑Year‑Old Books Held the Disease’s Traces

An international research team examined archaeological animal remains and historically animal‑skin parchment to uncover the history of the sheeppox virus (Sheeppox virus‑SPPV).

Among the works examined were important Middle‑Age manuscripts such as the roughly thousand‑year‑old York Gospels. Researchers detected traces of sheeppox virus DNA on the parchment pages of these works.

In the past, sheep, goat, and calf skins were widely used to produce books and documents. It turned out that the genetic traces left by the virus on the skins of infected animals could be preserved for centuries after parchment production.

Thus it became clear that the historical artifacts stored in libraries may carry not only records of human history but also genetic evidence of diseases that once spread among animals.

The virus's history stretched back 3,700 years

The researchers did not limit themselves to examining medieval manuscripts; analyses of sheep teeth dating from the Bronze Age also revealed traces of the virus.

Samples dated to around 1700 BCE constitute one of the oldest genetic evidences to date that the sheep‑pox virus has been circulating among domestic sheep flocks for roughly 3,700 years.

The findings suggest that the disease could have been a serious problem for societies engaged in animal husbandry across Eurasia for thousands of years.

The ancient books have been turned into a 'biological time capsule'.

One of the study's striking results was that historic manuscripts could serve as a new source for investigating the history of diseases.

Thanks to the preservation of DNA in animal skins over centuries, scientists can investigate which diseases circulated among animal herds in the past. For this reason, it is considered that the parchments stored in libraries and archives around the world may also contain traces of other viruses and pathogens that have not yet been discovered.

The Same Virus Triggered a Major Crisis in Greece

The sheep pox virus, which has existed for thousands of years, continues to threaten the livestock sector today.

The sheep and goat pox outbreak that began in Greece in August 2024 affected many farms. By 2026, under the measures implemented to prevent the spread of the disease, approximately half a million sheep and goats were slaughtered.

Data released as of May 2026 showed that the number of animals slaughtered exceeded 488,000.

Therefore, the phrase 'the virus killed about 500,000 animals' is considered less accurate than 'approximately 500,000 animals were slaughtered due to the outbreak.'

No Evidence of Transmission to Humans

The highly contagious sheep pox can cause fever, loss of appetite, eye and nasal discharge, and skin lesions in animals. The disease also reduces milk and meat production, lowers wool and hide quality, and can lead to serious economic losses in the livestock sector.

However, according to current scientific information, there is no evidence that the sheep pox virus causes infection in humans.

The study published in Science Advances revealed that traces of a virus the livestock sector is still battling today can still be found in thousands of years of animal remains and in the pages of medieval books, and it also shows that historical artifacts could be an unexpected source for illuminating the history of epidemic diseases.