Vikings are known for their intrepid maritime navigation, fearsome fighting, and extensive trade, but it appears that not only were they goods and weapons that they carried on their travels, but they could also have carried a deadly disease.
The researchers say they have found the world’s first confirmed case of smallpox, revealing that the disease spread throughout northern Europe during the Viking era.
“I think it is fair to assume that the Vikings have been the super-spreaders,” said Eske Willerslev, professor of ecology and evolution at Cambridge University and director of the Lundbeck Foundation Center for Geogenetics at the University of Copenhagen, who led the research.
Smallpox, a deadly infectious disease with symptoms including pus-filled blisters, is caused by the variola virus. Once described by eighteenth-century English physician Edward Jenner as the “most terrible scourge of the human species”, it is believed in the twentieth century alone that the disease killed between 300 and 500 million people.
A global vaccination program led the World Health Organization to declare the disease eradicated in 1980: the virus is now stored in only two laboratories in the world.
But despite its strong mark on human history, the origins of smallpox have remained murky.
The ancestor of the variola virus is believed to have crossed from rodents to humans thousands of years ago in Africa. In fact, written accounts and mummified remains, including those of Ramses V, suggest that smallpox may have been present in ancient Egypt. However, before the new investigation, the first case of smallpox confirmed by genetic data was that of a seventeenth-century boy found mummified in Lithuania.
Writing in the journal Science, Willerslev and colleagues report how, as part of a larger project studying the remains of 1,867 humans, they found smallpox virus DNA in the teeth or bones of 11 men and women from Denmark to Russia. , that dates from approximately 600 a. AD1050: a period that overlaps with the Viking era.
“It is the oldest confirmed case of smallpox,” said Willerslev.
While the researchers note that the 11 individuals were likely infected with the variola virus when they died, it is unclear whether it killed them. In fact, an individual from Oxford appears to have had a particularly creepy death, having been stabbed in the back as part of a widespread massacre of Danes or the murder of a group of Viking raiders.
The researchers extracted near-complete viral genomes from four of the individuals, with further analysis revealing that this now-extinct Viking-age smallpox virus differs from modern strains, likely evolving in parallel from a common ancestor that existed. about 1,700 years ago.
The team says the findings coincide with written reports that smallpox was found in western and southern Europe in the late 6th century, and it debunks the idea that the Normans introduced the disease to England or that the Crusaders brought it to Europe.
While it is unclear how or when modern forms of smallpox first appeared in Northern Europe, Willerslev said one possibility is that his ancestor was already present during the Viking era, but that it was simply less abundant than the newly discovered strain.
Crucially, Willerslev said, the findings shed light on the evolution of the variola virus and could even provide clues to how other smallpox diseases in animals could mutate and potentially pose a risk to humans.
Hendrik Poinar, director of the Ancient DNA Center at McMaster University, who was not involved in the work, described the research as exciting, but said the Viking-age smallpox virus is likely to remain a mystery given that researchers do not They could lead out of experiments.
However, Sanjoy Bhattacharya, professor of medical history and director of the World Health Organization Collaborating Center for Global Health Stories at York University, compared the findings to a “storm over a teacup.”
He said: “It is known from Egyptian mummies that smallpox existed in ancient times. We also know that trade links were widespread, and this carried disease throughout the world. So why should smallpox be a surprise among the Vikings?
