SHARP contributes to study of ancient hepatitis

A new study has been published tracing the evolution of the Hepatitis B virus from prehistory through to the present day [1]. SHARP Human Remains Team members Dr Sophie Beckett, Zannah Salter, and Dr Mel Van Twest contributed to the research released in the journal Science.

Hepatitis B virus (HBV) is a global concern, causing 820,000 deaths and 1.5 million new infections every year [2]. However, it is not just a modern issue: ancient DNA studies have shown that HBV has been infecting humans for thousands of years. A large team of researchers from around the world sought to investigate the past diversity and dispersal routes of HBV. They examined viral genomes from 137 ancient Eurasian and Native American people who lived between 10,500–400 years ago, including an individual from Sedgeford. The results mirror some well-known human migrations and demographic events, as well as revealing unexpected patterns.

The Sedgeford sample was collected from S1069 (Locky), an Anglo Saxon skeleton excavated in 1999 from a complex context in Reeddam and later studied by Lucy Koster as part of her undergraduate dissertation project [3]. Participants in the Human Remains courses may be familiar with S1069 who had fused vertebrae at the base of his spine – this skeleton and others will be investigated further during summer 2022. DNA was extracted from a cranial bone fragment from S1069 and sequenced at the Max Planck Institute

The results suggest that all modern types of HBV are descended from a strain that existed towards the end of the Pleistocene epoch. This strain infected the ancestors of the First Americans and their Eurasian relatives before these populations diverged. One lineage of the virus was then carried into the Americas, while another spread across Eurasia and eventually reached Africa and Oceania. This challenges the view that global HBV dispersal arose much earlier with human migrations out of Africa.

The authors also discovered that the virus was widespread in Europe before the Neolithic. “Many human pathogens are thought to have emerged after the introduction of agriculture, but HBV was clearly already affecting prehistoric hunter-gatherer populations,” says Prof Johannes Krause, director of the Department of Archaeogenetics at the Max Planck Institute for Evolutionary Anthropology and co-supervisor of the study. During the Neolithic transition in Europe, the HBV strains carried by hunter-gatherers were replaced by those of early farmers and these viral lineages prevailed for 4,000 years (Figure 3C in green).

Figure 3C from the article: Geographic distribution of ancient European HBV genomes within different time-periods, colored by genetic lineage.

One of the most surprising findings was that HBV genetic diversity collapsed in Europe during the 2nd millennium BCE. “This could point to important changes in epidemiological dynamics over a very large region during this period, but we will need more research to understand what happened,” says Dr Arthur Kocher, lead author and researcher in the tide group. The HBV strains that replaced them were more similar to modern types, as shown by the later European samples (including Sedgeford). A fascinating twist was that one prehistoric viral lineage survived this upheaval, eventually giving rise to a rare modern HBV genotype that expanded globally during the HIV pandemic.

Zannah Salter

References:

[1] Kocher et al (2021) Ten millennia of Hepatitis B virus evolution. Science 374(6564): 182-188. DOI: https://doi.org/10.1126/science.abi5658

[2] World Health Organisation Hepatitis B fact sheet https://www.who.int/news-room/fact-sheets/detail/hepatitis-b

[3] Koster (2020) Disarticulation in the past and present: A study of the disturbance of human remains at Sedgeford Anglo-Saxon cemetery, Norfolk. University of Oxford undergraduate dissertation.