Stone Age and Medieval Hepatitis B Virus decoded

A team of researchers not only recovered ancient viral DNA from skeletons but also reconstructed the genomes of three strains of Hepatitis B Virus.

[Skeletal remains of HBV positive individual from the Stone Age site of Karsdorf (Germany). The individual was a male who died ataround 25-30 years. – Credit: Nicole Nicklisch]

For this study, the researchers analyzed samples from the teeth of 53 skeletons excavated from Neolithic and medieval sites in Germany[1]. The remains dated from around 5000 BC to 1200 AD. The researchers screened all samples for viral pathogens and detected ancient Hepatitis B Virus in three of the individuals. Full Hepatitis B Virus genomes were recovered from these samples, two of which were from the Neolithic period, dating to about 7000 and 5000 years ago, and one from the medieval period[2]. The Neolithic genomes represent the by far oldest virus genomes reconstructed to date.

Interestingly, the ancient virus genomes appear to represent distinct lineages that have no close relatives today and possibly went extinct. The two Neolithic genomes, although recovered from individuals that lived 2000 years apart, were relatively similar to each other in comparison with modern strains, and were in fact more closely related to modern strains of Hepatitis B Virus found in Chimpanzees and Gorillas. In contrast, the medieval Hepatitis B Virus genome is more similar to modern strains, but still represents a separate lineage. This is the case even when it is compared to two previously published Hepatitis B Virus genomes recovered from mummies dating to the 16th century. The Hepatitis B Virus strains found in these mummies are closely related to modern strains, suggesting a surprising lack of change in the virus over the last 500 years.

These findings point to a complicated history for the virus, which may have involved multiple cross-species transmission events.

[1] Ben Krause-Kyora et al: Neolithic and Medieval virus genomes reveal complex evolution of Hepatitis B in eLife – 2018
[2] Patterson Ross et al: The paradox of HBV evolution as revealed from a 16th century mummy in PloS Pathogens - 2018