Two stories on the Black Death – one at https://phys.org/print435308864.html … and https://phys.org/print435312986.html … at the first one we learn about analysis of thousands of skeletons. Genetic material from infectious diseases such as tuberculosis and the plague leave fossil traces of themselves in human teeth. A molecular fossil record was used to build a genetic profile of Yersinia pestis – the organism behind bubonic plague. The research team were able to trace the disease back to the Stone Age – which was a surprise. They also found a strong connection with the Plague of Justinian in the 6th century AD – as well as the Black Death that decimated the population of Europe in the late 14th century AD. In doing so the full genome of Yersinia pestis was reconstructed.
The second link is perhaps the most interesting one as the first discovery tended to support the mainstream view – the plague was spread in all likelihood by fleas riding on the backs of rats. In contrast in the second paper (published by PNAS in January 2018) we are told the bacterium involved was Yersinia pestis which moved from victim to victim very quickly – and we may note it moved from one geographical region to another at an incredible speed. Until now, we are told, it was thought the leas lived on the rats – and jumped from their hosts. It was obvious this is based on an assumption and it seems scientists now realise this idea is tenuous – and cannot account for the rapidity of the spread of the pandemic. However, instead of looking at a spread via the atmosphere, the new paper suggests that human fleas and body lice were responsible for the spread of the plague. The assumption behind this theory must be that humans were unhygienic in the 14th century (not just the peasants but the nobs as well as all sections of society succombed to the plague). It sounds a bit strained – but they have moved the goal posts and hope to keep the mainstream theory alive.Interestingly, they amassed a considerable amount of data from mortality records and went on to create a mathematical model to demonstrate how each outbreak spread. They even had the option of airborne transmission they say (as in modern bird flu) but their model came out in support of human fleas and lice and humans who didn't like having a bath.
If the Yersinia pestis bacterium was in the atmosphere, as suggested by Mike Baillie in his book, 'New Light on the Black Death', that would allow the disease to spread extremely fast – which is slightly different from airborne which appears to be confined to the very lower parts of the atmosphere (where birds spread their wings). We shall have to wait to see how mainstream reacts.