Study Reveals Sheeppox Virus DNA Found in Medieval Manuscripts

<p>Sheeppox is a highly contagious viral disease that was largely eradicated from much of European livestock in the 20th century. However, regional outbreaks still occur, such as one that affected sheep flocks in Greece last year. To understand the evolution of the virus over the last 3,500 years, scientists extracted and sequenced sheeppox DNA preserved in the animal skins used for parchment in various medieval manuscripts. Their findings were published in a paper in the journal Science Advances.</p><p>Co-author Louis L’Hôte, a graduate student at University College Dublin, stated, “The recording of ancient DNA of pathogens has completely changed our understanding of infectious disease in the past, and here we show that parchment can also preserve animal pathogen DNA. It is possible that archives and libraries around the world also contain the genetic traces of disease outbreaks in animals in the past.” He added that these genomes help in understanding how these pathogens evolved and their impact on past societies, noting that the sheeppox virus has affected Eurasian sheep herds for at least three and a half millennia.</p><p>The earliest known written evidence of sheeppox infection dates to the first century CE, with Roman accounts describing outbreaks of skin lesions in sheep. More frequent mentions of deadly outbreaks occurred during the Middle Ages, recorded in agricultural texts and accounting documents from France, Spain, and England. There was a decline in outbreaks in 17th-century France, but they re-emerged in the 18th and 19th centuries, often with high mortality rates in flocks. Great Britain did not experience a resurgence of sheeppox until 1847.</p>