<P> The historian Francis Aidan Gasquet wrote about the Great Pestilence in 1893 and suggested that "it would appear to be some form of the ordinary Eastern or bubonic plague". He was able to adopt the epidemiology of the bubonic plague for the Black Death for the second edition in 1908, implicating rats and fleas in the process, and his interpretation was widely accepted for other ancient and medieval epidemics, such as the Justinian plague that was prevalent in the Eastern Roman Empire from 541 to 700 CE . </P> <P> An estimate of the mortality rate for the modern bubonic plague, following the introduction of antibiotics, is 11% (by the US Centers for Disease Control (CDC)), although it may be much higher in economically or medically underdeveloped regions . Symptoms of the disease include fever of 38--41 ° C (100--106 ° F), headaches, painful aching joints, nausea and vomiting, and a general feeling of malaise . Left untreated, of those that contract the bubonic plague, 80 per cent die within eight days . Pneumonic plague has a mortality rate of 90 to 95 per cent . Symptoms include fever, cough, and blood - tinged sputum . As the disease progresses, sputum becomes free - flowing and bright red . Septicemic plague is the least common of the three forms, with a mortality rate near 100% . Symptoms are high fevers and purple skin patches (purpura due to disseminated intravascular coagulation). In cases of pneumonic and particularly septicemic plague, the progress of the disease is so rapid that there would often be no time for the development of the enlarged lymph nodes that were noted as buboes . </P> <P> A number of alternative theories--implicating other diseases in the Black Death pandemic--have also been proposed by some modern scientists (see below--"Alternative Explanations"). </P> <P> In October 2010, the open - access scientific journal PLoS Pathogens published a paper by a multinational team who undertook a new investigation into the role of Yersinia pestis in the Black Death following the disputed identification by Drancourt and Raoult in 1998 . They assessed the presence of DNA / RNA with polymerase chain reaction (PCR) techniques for Y. pestis from the tooth sockets in human skeletons from mass graves in northern, central and southern Europe that were associated archaeologically with the Black Death and subsequent resurgences . The authors concluded that this new research, together with prior analyses from the south of France and Germany, "ends the debate about the cause of the Black Death, and unambiguously demonstrates that Y. pestis was the causative agent of the epidemic plague that devastated Europe during the Middle Ages". </P>

When did the black death start and end