Viking raiders were responsible for spreading the deadly smallpox to Britain and around the globe, genetic information extracted from ancient teeth has revealed.
The teeth samples contained extinct strains of smallpox — different to the modern virus that was declared eradicated in 1980 — that dated back to the 7th Century.
The findings indicate that smallpox was widespread in northern Europe during that period — pushing back the disease’s first known case by some 1,000 years.
Smallpox is a viral infection that causes a fever, vomiting, headaches and a rash which turns into disfiguring sores and pustules that could leave permanent scars.
In around 30 per cent of cases, smallpox infection proved fatal.
The international research team said that it is unclear if the ancient smallpox strains were as deadly — but that the Vikings likely helped the spread of the disease.
Knowing more about the evolutionary history of viruses such as smallpox, they added, may help in the battle against new and emerging infectious diseases.
Viking raiders were responsible for spreading the deadly smallpox to Britain and around the globe, genetic information extracted from ancient teeth has revealed. Pictured, a 1,200-year-old, smallpox-infected Viking skeleton unearthed from Öland, an island in the south of Sweden
‘Knowledge from the past can protect us in the present,’ said paper author and computational biologist Terry Jones of the University of Cambridge.
‘When an animal or plant goes extinct, it isn’t coming back. But mutations can re-occur or revert and viruses can mutate or spill over from the animal reservoir.’
‘So there will always be another zoonosis — a disease which can be transmitted to humans from animals,’ he explained.
Caused by the variola virus, smallpox was one of the most hostile human diseases, killing more than 300 million people in the 20th century alone.
This virus became the first human disease to be eradicated — with the last natural case reported in Somalia in 1977 — following an extensive global vaccination effort.
However, concerns remain that the virus could re-emergence, with the possibility of another strain spilling over from animals at any moment.
Scientists say that the exact origin and evolution of smallpox in humans remains a mystery — however, some virologists believe that the variola virus may have been first transmitted to humans from rodents thousands of years ago.
To find out more, Dr Jones and colleagues searched for evidence of ancient smallpox at various archaeological sites.
The teeth samples contained extinct strains of smallpox — different to the modern virus that was declared eradicated in 1980 — that dated back to the 7th Century. Among the specimens examined by Dr Jones and his colleagues were massacred 10th-century Vikings, pictured, found in a mass grave located within St John’s College, Oxford
The team found extinct strains of the variola virus in the skeletons of humans at 11 different burial sites — located in Denmark, Norway, Russia and the UK — and all from the Viking era.
More evidence of these viral strains was found in human remains from Öland, an island that lies off of the southeast coast of Sweden.
Analysis revealed that the genetic structures of the ancient smallpox strains were ‘remarkably’ different from their modern counterpart — suggesting the virus evolved, the researchers said.
The findings indicate that smallpox was widespread in northern Europe during that period — pushing back the disease’s first known case by some 1,000 years. Among the specimens examined by Dr Jones and his colleagues were massacred 10th-century Vikings, pictured, found in a mass grave located within St John’s College, Oxford
‘We discovered new strains of smallpox in the teeth of Viking skeletons and found their genetic structure is different to the modern smallpox virus eradicated in the 20th century, said paper author and St John’s, Cambridge zoologist Eske Willerslev.
‘We already knew Vikings were moving around Europe and beyond — and we now know they had smallpox.’
‘People travelling around the world quickly spread COVID-19 — and it is likely Vikings spread smallpox. Just back then, they travelled by ship rather than by plane.’
‘We don’t know for sure if these strains of smallpox were fatal and caused the death of the Vikings we sampled,’ added paper author and evolutionary historian Martin Sikora of the University of Copenhagen.
However, he added, these Vikings ‘certainly died with smallpox in their bloodstream for us to be able to detect it up to 1,400 years later.’
The full findings of the study were published in the journal Science.