The sheeppox virus, a highly contagious and frequently fatal disease, was largely eliminated from European livestock during the 20th century, though isolated outbreaks still occur, such as the recent incidents in Greece. To trace the pathogen’s evolutionary history over the past 3,500 years, researchers analyzed DNA preserved within the animal skins used to create parchment for various medieval manuscripts. These findings were detailed in a recent publication in the journal Science Advances.
“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,” explained co-author Louis L’Hôte, a graduate student at University College Dublin. “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 provide critical insights into how such pathogens evolved and affected historical societies.
According to the study, the earliest documented references to sheeppox date back to the first century CE, when Roman writers described outbreaks of skin pustules in livestock. References to deadly “pockes” or “variola” became more common in medieval agricultural texts and accounts from France, Spain, and England. While outbreak frequency appeared to decline in 17th-century France, severe epidemics resurfaced during the 18th and 19th centuries. Great Britain, notably, did not see a resurgence of the disease until 1847.
Leave a Reply