Sacred pages of 1,000-year-old gospel reveal ancient DNA scientists never expected

The discovery, which centered on the York Gospels, was announced by University College Dublin (UCD) in early September.

The highly contagious disease affects sheep but is not known to infect humans. Researchers detected its DNA in the animal skins used to make parchment, according to the university.

Unexpectedly, researchers found traces of sheeppox virus on parchment made from calfskin and goatskin, suggesting either cross-species infections or contamination during the parchment-making process.

In a statement, UCD described the York Gospels as a "biological time capsule" that preserved evidence of the virus for centuries.

"The research reveals that sheeppox has threatened livestock for more than 3,700 years," the university said.

"A highly contagious disease, sheeppox spreads rapidly and can affect large portions of a flock in a short time," UCD said.

"The disease is particularly dangerous because it can cause very high mortality rates, especially in young animals, and dramatically reduce productivity by damaging wool, meat and milk yields."

Louis L'Hôte, a Ph.D. candidate at UCD who was the lead author of the study, told university officials that the discovery shows parchment can preserve traces of animal pathogen DNA for centuries.

"These genomes help us understand how these pathogens evolved and how they affected past societies - such as sheeppox virus, which we show has been affecting Eurasian sheep herds for at least three-and-a-half millennia."

L'Hôte added that the pathogen remains a threat today - and that studying its ancient DNA could help researchers better understand how to eradicate it.

"We find that unlike the smallpox virus, the sheeppox virus genome was very stable over the last few millennia," he added.

"This might mean that genetic changes before this point were very important to how the sheeppox virus evolved to infect its host, which may help us fight the pathogen in the future," he added.

Fox News Digital reached out to L'Hôte for further comment and insight. 

A growing number of ancient DNA discoveries have shed new light on diseases that afflicted humans and animals centuries ago.