A group of researchers has found traces of smallpox in Vikings in Norway, Sweden, and Denmark, which reveals that the disease arrived in Europe much earlier than expected.
The earliest genetic evidence of the smallpox virus dates back to the 17th century, but must now be moved back in time almost 1,000 years, according to an international research team led by the University of Copenhagen.
“We have positive findings in Denmark, Sweden, northern Norway, Oxford in England, and the European part of Russia. So it is a big spread”, Martin Sikora at the University of Copenhagen told the Danish scientific portal Videnskab.
Their research paper in the journal Science described the virus in the remains of at least eleven people from Northern Europe (600-1050 AD). The virus was widespread in society, the researchers believe. It is therefore likely that many Vikings lost their lives due to the disease as the virus has been detected in 2 percent of the remains examined.
Archaeologist and DNA researcher Søren Michael Sindbæk argued that smallpox may have been a part of society, a bit like the flu is today, without causing mass death.
“In that case, one would find mass graves or very localised eruptions. When the disease is widespread in many places, it indicates that people were exposed to it regularly, but did not die from it”, he said
The findings may in the long run provide key answers to questions such as how a virus like smallpox moves from animals to humans and how it mutated into a threat to humans. Researchers have been able to reconstruct over 95 percent of the genome of the virus in various bodies. They have concluded that the virus is of a different genetic variant, but stems from the same ancestor, as the virus that raged in the 20th century.
“Many of the diseases we as a society take most seriously today are those that first have a high mortality rate, and against which we later develop higher immunity. But smallpox is an example of the opposite: the disease became more deadly over time", Sindbæk stressed. “If anyone is in doubt after the last few months, then major epidemic diseases are something that can topple society. We can clearly use these findings to become better at facing some of the diseases that can significantly affect society”, Sindbæk told Videnskab.
Until now, a mummy from Lithuania dating back to the 17th century has been thought of as the earliest source of the smallpox. Therefore, it has been argued that the disease was not present in Europe in the Middle Ages, but arrived with knights from the Crusades in the Middle East – a version that may become obsolete due to the new finds.
Smallpox is one of the deadliest diseases that mankind has ever experienced, killing at least 500 million people in the 20th century alone. The last detected case of smallpox was recorded in Somalia in 1977.
The course of the disease is described as a strong fever followed by a rash that develops into fluid-filled blisters. The risk of death following contracting the disease was about 30 percent, with higher rates among babies. Survivors of smallpox had extensive scarring on their skin, and some were left blind. A successful vaccination campaign led to the disease being pronounced eradicated in 1980.