An international team of researchers analyzed two genomes of the oldest known causative agents of the bubonic plague, dating back 3,800 years. Scientists believe they have discovered a strain of the plague bacillus, which is the ancestor of the infection that caused the Black Death, the Justinian plague and the third plague pandemic in China. This was announced in a press release on Phys.org.
The bacterium Yersinia pestis is the cause of deadly pandemics in the era of the Ancient World, the Middle Ages and the New Age. Scientists analyzed a number of ancient microbial samples from the Late Neolithic and Early Bronze Age, but they did not possess the genes characteristic of virulent strains. In particular, they lacked the DNA necessary to survive in fleas, which are the vector (carrier) of the plague bacillus among mammals.
New strains were isolated from two victims of the disease, buried in the same grave about four thousand years ago. The results of genetic analysis showed that the human remains belong to the Timber Cultural and Historical Community, common in the steppe and forest-steppe belts of Eastern Europe. They died from the same plague bacillus strain.
It was shown that microorganisms possessed all the genes necessary for the development of the bubonic form of the disease. The find makes it possible to postpone the appearance of the dangerous form of the plague bacillus, which can infect rodents, humans and other mammals, by 1000 years.
In January of this year, researchers from universities in Oslo and Ferrara said the bubonic plague pandemic in medieval Europe, called the Black Death, was caused not by rats, but by humans. Fleas and lice parasitizing humans contributed to the spread of the disease. The pandemic occurred in Europe and Asia in 1347-1351 and killed more than 25 million people (in some regions, up to half of the population died out).