̽��ֱ�� of Cambridge - Barbara Mühlemann

Vikings had smallpox and may have helped spread the world’s deadliest virus

Anonymous — Thu, 23 Jul 2020 18:30:46 +0000

Smallpox spread from person to person via infectious droplets, killed around a third of sufferers and left another third permanently scarred or blind. Around 300 million people died from it in the 20th century alone before it was officially eradicated in 1980 through a global vaccination effort – the first human disease to be wiped out.

Now an international team of scientists have sequenced the genomes of newly discovered strains of the killer virus after it was extracted from the teeth of Viking skeletons from sites across northern Europe. ̽��ֱ��findings are published today in the journal Science.

“We already knew Vikings were moving around Europe and beyond, and we now know they had smallpox. Just as people travelling around the world today quickly spread COVID-19, it is likely Vikings spread smallpox. Only back then, they travelled by ship rather than plane,” said Professor Eske Willerslev in the ̽��ֱ�� of Cambridge’s Department of Zoology and St. John’s College, and Director of ̽��ֱ��Lundbeck Foundation GeoGenetics Centre at the ̽��ֱ�� of Copenhagen, who led the study.

̽��ֱ��team found smallpox - caused by the variola virus - in 11 Viking-era burial sites in Denmark, Norway, Russia, and the UK. They also found it in multiple human remains from Öland, an island off the east coast of Sweden with a long history of trade.

They were able to reconstruct near-complete variola virus genomes for four of the samples. ̽��ֱ��genetic structure of this earliest-known smallpox strain is different to the modern smallpox virus eradicated in the 20th century.

“There are multiple ways viruses may diverge and mutate into milder or more dangerous strains. This is a significant insight into the steps the variola virus took in the course of its evolution,” said Dr Barbara Mühlemann, formerly at the Centre for Pathogen Evolution at the ̽��ֱ�� of Cambridge, now based at the Institute of Virology at Charité – Universitätsmedizin Berlin, and one of the first authors of the report.

Historians believe smallpox may have existed since 10,000 BC but until now there was no scientific proof that the virus was present before the 17th century. It is not known how it first infected humans but, like COVID-19, it is believed to be a zoonotic disease - one that originated in an animal.

Smallpox was eradicated throughout most of Europe and the United States by the beginning of the 20th century but remained endemic throughout Africa, Asia, and South America. ̽��ֱ��World Health Organisation launched an eradication programme in 1967 that included contact tracing and mass communication campaigns - all public health techniques that countries have been using to control today’s coronavirus pandemic. But it was the global roll-out of a vaccine that ultimately enabled scientists to stop smallpox in its tracks.

While it is not clear whether these ancient strains of smallpox were fatal, the Vikings must have died with smallpox in their bloodstream for the scientists to detect it up to 1400 years later. It is also highly probable there were epidemics earlier than these findings.

“While written accounts of disease are often ambiguous, our findings push the date of the confirmed existence of smallpox back by a thousand years,” said Dr Terry Jones at the Centre for Pathogen Evolution at the ̽��ֱ�� of Cambridge and the Institute of Virology at Charité – Universitätsmedizin Berlin, and one of the senior authors who led the study.

He added: “To find smallpox so genetically different in Vikings is truly remarkable. No one expected that these smallpox strains existed. It has long been believed that smallpox was in Western and Southern Europe regularly by 600 AD, around the beginning of our samples. We have proved that smallpox was also widespread in Northern Europe. Returning crusaders or other later events have been thought to have first brought smallpox to Europe, but such theories cannot be correct.”

“Smallpox was eradicated, but another strain could spill over from the animal reservoir tomorrow. What we know in 2020 about viruses and pathogens that affect humans today is just a small snapshot of what has plagued humans historically,” said Willerslev.

This research is part of a long-term project sequencing 5000 ancient human genomes and their associated pathogens. It was made possible thanks to a scientific collaboration between ̽��ֱ��Lundbeck Foundation, ̽��ֱ��Wellcome Trust, ̽��ֱ��Nordic Foundation, and Illumina Inc.

Reference

Muhlemann, B. et al. 'Diverse variola virus (smallpox) strains were widespread in northern Europe in the Viking Age. Science, July 2020. DOI: 10.1126/science.aaw8977

Adapted from a press release by St John’s College, Cambridge.

Scientists have discovered extinct strains of smallpox in the teeth of Viking skeletons – proving for the first time that the killer disease plagued humanity for at least 1400 years.

Just as people travelling around the world today quickly spread COVID-19, it is likely Vikings spread smallpox. Only back then, they travelled by ship rather than plane.

Eske Willerslev

Thames Valley Archaeological Services

Massacred 10th century Vikings found in a mass grave at St John’s College, Oxford

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Oldest genetic evidence of Hepatitis B virus found in ancient DNA from 4,500 year-old skeletons

Anonymous — Wed, 09 May 2018 17:00:00 +0000

A pioneering study has identified the oldest evidence of HBV in the ancient remains and proved that viruses can become extinct. ̽��ֱ��scientific significance of the research has been described as ‘truly remarkable’ and compared to the discovery of the first fossils.

Today the Hepatitis B virus affects millions of people worldwide. In 2015 it was estimated that approximately 257 million people were chronically infected with HBV and 887,000 died due to associated complications such as liver cancer.

̽��ֱ��new research, led by a group of academics at the Centre for Pathogen Evolution in the Department of Zoology at the ̽��ֱ�� of Cambridge and the Centre for GeoGenetics at the ̽��ֱ�� of Copenhagen, took genetic samples from skeletons across Europe and Asia from the Bronze Age to the Medieval period, and found 25 HBV-positive skeletons amongst the remains. In 12 of these skeletons, they found enough of the HBV genome to perform detailed analyses - the oldest of which was 4,500-years-old.

From this data they were able to extract the genetic sequences of HBV that infected the individuals thousands of years ago.

̽��ֱ��findings, published in the journal Nature, present new insights into the origins and evolution of HBV. ̽��ֱ��genetic makeup of this strain could have implications for improving vaccines for HBV.

Before this study, the oldest human viruses to be discovered were approximately 450-years- old but most are no more than 50-years-old. ̽��ֱ��research now forms the oldest and largest datasets scientists have of ancient human viruses.

Barbara Mühlemann, joint first author on the research paper and a graduate student at the ̽��ֱ�� of Cambridge, said: “People have tried to unravel the history of HBV for decades - this study transforms our understanding of the virus and proves it affected people as far back as the Bronze Age. We have also shown that it is possible to recover viral sequences from samples of this age which will have much wider scientific implications.”

Although HBV is a global health issue, little is known about its origin and evolution. As with many human viruses, this is largely due to a lack of historical evidence which has been difficult to locate and identify.

Dr Terry Jones, joint first author who is based at the ̽��ֱ�� of Cambridge’s Department of Zoology, explained: “Scientists mostly study modern virus strains and we have mainly been in the dark regarding ancient sequences – until now. It was like trying to study evolution without fossils. If we only studied the animals living today it would give us a very inaccurate picture of their evolution – it is the same with viruses.”

Understanding more about HBV may now be possible. Showing that the virus has been circulating in humans since at least the Bronze Age is a big scientific advancement, as previous attempts to estimate how long the virus has infected humans have ranged from 400 years to 34,000 years.

̽��ֱ��study was led by Professor Eske Willerslev, who holds positions both at St John’s College, ̽��ֱ�� of Cambridge, and the ̽��ֱ�� of Copenhagen.

He said: “This data gives us an idea of how this virus behaves, and it provides us with a better idea of what is biologically possible in the future. Analysis of other ancient DNA samples may reveal further discoveries and this pioneering study could have huge implications for how the virus affects humans today.”

̽��ֱ��research also shows the existence of ancient HBV genotypes in locations incompatible with their present-day distribution, contradicting previously-suggested geographical origins of the virus.

Professor Willerslev initially suspected that it might be possible to find viruses in human remains based on previous research during his role at the ̽��ֱ�� of Copenhagen. He approached Mühlemann and Jones who have specialised in identifying and studying the evolution of viruses.

̽��ֱ��research approach the group used in the study, called ‘shotgun sequencing’, looks at all genetic material present in a sample, as opposed to ‘genome bio-capture’ which focuses only on the human genome.

Professor Willerslev said: “This study is just the start. We’re talking about one virus here, but there are a lot of other viruses we could look for.”

Reference:
Barbara Mühlemann et al. 'Ancient Hepatitis B viruses from the Bronze Age to the Medieval period.' Nature (2018). DOI: 10.1038/s41586-018-0097-z

An extinct strain of the human Hepatitis B virus (HBV) has been discovered in Bronze Age human skeletons found in burial sites across Europe and Asia.

This study could have huge implications for how the virus affects humans today.

Eske Willerslev

Alexey A. Kovalev

Mass burial of battle victims from the Xiongnu period in Omnogobi, Mongolia, from which scientists extracted ancient DNA from for the study.

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