Bacteria Behind London's Great Plague ID'd

A skull is uncovered at the Bedlam burial ground where it is believed over 20,000 Londoners were buried between 1569 and 1738.

Using DNA testing, scientists have confirmed the identity of the bacteria that caused London's Great Plague in the 17th century, reports the BBC.

From 1665 - 1666 the bubonic plague killed 100,000 people in London, almost a quarter of the city's entire population. The disease spread rapidly and burial pits were sometimes created to accommodate the overwhelming number of bodies.

Last year, archaeologists in London believe they came upon one of these pits as excavations were underway at a former burial ground at Liverpool Street for a new rail link across the city, reported CNN. The bodies looked to be buried on the same day as others in the nearby Bedlam cemetery with headstones reading 1665, further leading scientists to believe those in the burial pit were killed by the plague.

During the course of this year-long excavation, 3,500 skeletons have been uncovered.

The osteology department at the Museum of London Archaeology, where all the finds from the Liverpool Street excavation were examined, searched for Yersinia pestis in the skeletons, a bacterium known to cause plague. Teeth were removed from the other remains and sent to the Max Planck Institute for the Science of Human History in Germany for further testing.

Molecular palaeopathologist Kirsten Bos found positive results for Yersinia pestis in the teeth of five out of 20 skeletons she examined, confirming this is the bacteria that caused the bubonic plague.

"We could clearly find preserved DNA signatures in the DNA extract we made from the pulp chamber and from that we were able to determine that Yersinia pestis was circulating in that individual at the time of death," she told the BBC.

Read more at Discovery News