Plague DNA identified in Bronze Age remains

The bacteria that caused the Justinian Plague in the 6th century AD and the Black Death in the 14th century AD – Yersinia pestis – has recently been identified in three individuals from two Bronze Age sites in Britain. While a Late Neolithic and Bronze Age (LNBA) lineage of Y. pestis has previously been found across Continental Europe, this is the first evidence that the disease had also made its way to Britain during this time. 

An international team led by researchers from the Francis Crick Institute screened human remains from two Bronze Age sites for evidence of pathogen DNA. The first location was Charterhouse Warren Farm in Somerset, which is an unusual mass burial site where human remains appear to have been interred together in a natural shaft. Thirty of the individuals from the site were analysed as part of this study, and Y. pestis was found in two sampled teeth, one from a child 12±3 years old and the other 10±3 years old. The mandible of the c.12-year-old was radiocarbon dated to 4145-3910 cal BP. The second site analysed was Levens Park ring cairn in Cumbria. Four burials have been found there in total, containing one complete and three disturbed skeletons, dated to 4300-3700 cal BP. All four were analysed, and Y. pestis was identified in one of them: a 35- to 45-year-old woman who had been buried in a plank-lined grave along with sherds of Beaker pottery.  

Photo of the natural shaft at Charterhouse Warren, taken in the 1970s, where an unusual Bronze Age mass burial site was discovered. Two children interred there were recently found to have had plague.  

While only three individuals tested positive for Y. pestis in this study, rates of false negative results in archaeological remains are likely to be quite high due to preservation bias, so it is possible that other individuals from each site were also infected. In the case of Charterhouse Warren, this raises the question of whether their unusual burial circumstance was due to an outbreak of the disease. Complicating the matter, however, is the fact that many of the remains display evidence of violence that occurred at or around the time of death. Were these individuals then the victims of an attack and just happened also to have plague? Or were they possibly killed because of their infected status? It is worth noting, though, that the woman with plague at Levens Park appears to have been buried in keeping with typical funerary practices of her time. 

Whatever the circumstances of their deaths, all three individuals were found to have had a sub-lineage of the LNBA plague which had lost the ymt gene, known as LNBA ymt−. The absence of this gene means it was unlikely that the LNBA plague was transmitted by fleas and therefore it must have mostly been spread by person-to-person contact. The absence of any clear archaeological evidence for major societal shocks in Late Neolithic and Bronze Age Europe, comparable to what is evidenced during the major plague outbreaks in the 6th and 14th centuries AD, has led to questions about whether the LNBA plague was as virulent or as deadly as the later strains. As this LNBA ymt− type has been found across Eurasia and has now been identified in two disparate regions of Britain, however, it seems that this strain was fairly widespread during the Bronze Age. 

The results were recently published in Nature Communications: 

Photo: Tony Audlsey