DNA extract identifies the oldest cases of bacterial plague in Britain
To test for the presence of bacteria, scientists collected teeth samples from 34 skeletal remains.
A new study has discovered the oldest instance of bacterial plague in Britain to date.
The Francis Crick Institute-led study detected evidence of three 4,000-year-old cases of bacterial plague caused by Yersinia pestis.
According to the study, two cases of this bacterial infection were identified from the human remains in a mass burial site of Charterhouse Warren in Somerset and one from the ring cairn monument in Levens, Cumbria.
DNA analysis via dental pulp
To test for the presence of bacteria, they collected teeth samples from 34 skeletal remains buried in these two locations.
After that, the samples were placed in a clean room facility to extract the dental pulp, which can hold DNA remnants for thousands of years. According to scientists, these DNA remains can reveal whether or not a person was infected with this bacterial disease, as well as their age and gender.
Out of 34 samples, they discovered plague infection in two children aged 10 to 12 years old at the time of death and one woman aged 35 to 45. Meanwhile, radiocarbon dating revealed that all of these people died at the same time.
Previous research has found plague cases in people from Eurasia between 5,000 and 2,500 years ago (BP). However, the new study points out that no such cases have been identified in Britain, particularly during the above period.
Study to understand historical plague cases
The authors highlight that the “wide geographic spread” of this bacterial strain of the plague suggests that it was easily transmitted during that time
The team suspects other people buried at these sites may have been infected with Yersinia pestis. According to the study, these mass burial sites were not associated with a plague outbreak, but individuals may have been infected at their death. However, it wasn’t easy to determine because pathogenic DNA degrades quickly in samples.
Despite the few cases identified, the research opens the door to a better understanding of historical plague cases in humans.
“The ability to detect ancient pathogens from degraded samples, from thousands of years ago, is incredible. These genomes can inform us of the spread and evolutionary changes of pathogens in the past, and hopefully help us understand which genes may be important in the spread of infectious diseases. We see that this Yersinia pestis lineage, including genomes from this study, loses genes over time, a pattern that has emerged with later epidemics caused by the same pathogen,” said Pooja Swali, first author and Ph.D. student at the Crick, in an official release.
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