Researchers find hepatitis B virus in stone age skeletons
With over 250 million people infected worldwide, hepatitis B viruses are among the most common pathogens. The virus can cause severe inflammation of the liver, which in the worst case can even be fatal. Hepatitis seems to be an old acquaintance of mankind. Apparently, Stone Age people were already plagued by hepatitis. Researchers from the University of Kiel recently found a strain of ancient hepatitis B viruses in studies of 7,000-year-old skeletons. Using the samples, the scientists were able to understand the evolution of hepatitis.
An international team of researchers led by the Christian Albrechts University in Kiel (CAU) and the Max Planck Institute for Human History (MPI) in Jena found hepatitis B viruses in Stone Age human skeletons. The scientists succeeded in reconstructing the Stone Age viruses. These are strains of the hepatitis B virus (HBV). According to the results, it has been circulating in Europe for at least 7,000 years. The research results were recently published in the specialist journal "eLIFE".
The hepatitis virus has also changed
The viruses discovered are similar to today's strains, but represent their own lineage. The researchers suspect that this has already died out. Similar variants of "Stone Age hepatitis" occur today in chimpanzees and gorillas. Not much has been known about the history and epidemiology of hepatitis. The researchers in Kiel have now successfully reconstructed viral Stone Age DNA for the first time. This opened up valuable information on the origin and evolution of the viruses.
The oldest known virus to date
The scientists extracted the Stone Age viruses from tooth samples from two Neolithic individuals. In addition, samples from a medieval skeleton could be obtained. This made it possible to reconstruct three strains of hepatitis. The oldest strain is around 7000 years old and thus represents the oldest genetically proven viral pathogen to date.
The evolution of hepatitis B
The Stone Age pathogens are most similar to the hepatitis viruses that are found today in human primates such as chimpanzees and gorillas. In contrast, the medieval variant is more similar to today's strains, but still represents its own lineage. The researchers report that the virus has undergone surprisingly little changes in the past 500 years. They suspect that there have been multiple transmissions between humans and non-human primates over the past 7000 years.
Relationship between lifestyle and virus occurrence
"We are investigating whether there is a connection between the emergence of diseases and fundamental changes in people's way of life in prehistory and early history," reports the co-author of the Almut Nebel study in a press release from the University of Kiel on the study results. Thanks to modern methods, the researchers were able to decipher these relationships.
The possibilities of modern DNA research
“A lot has happened since we started researching old human and pathogenic DNA at the CAU,” explains the first author of the study, Ben Krause-Kyora. New analytical methods such as proteomics would broaden the range of methods to better examine old diseases and the human genome against an archaeological and medical background.
"Our results show the great potential of aDNA (old DNA) obtained from human bones", summarizes Johannes Krause, Director of the Archaeogenetics Department at the MPI for Human History. The aDNA allows the evolution of blood-borne viruses to be researched. So far, it has always been doubtful whether it is possible to detect such diseases from past times at all. Now there is a powerful tool to explore the complex evolutionary history of viral diseases, said Krause. (vb)