Black death spread by humans?
Chris Duncan, at Liverpool University and Sue Scott, have published a theory in their new book, The Return of the Black Death, that the Black Death was not passed on by fleas on rats carrying bubonic plague, as was thought until now, but that the disease was haemorrhagic plague – an equally infectious disease, but one carried by humans and not fleas.
Duncan and Scott became convinced that rats were not the cuplrits after examining comtemporary accounts of the plague – in Penrith, in Cumbria, they examined original parish registers dating back to 1538 and noted that after a stranger died of the plague it was 22 days before a rash of further deaths occured. Twenty two days was an exceptionally long incubation period. Further research showed that the average incubation period was 27 days, which is about that of haemorrhagic plague. The reported symptoms also fit haemorrhagic plague better than those of bubonic plague.
Worryingly, the authors predict it will inevitably re-emerge sometime in the future – a killer which could have even more potential to spread around the world than the Sars virus.