> http://www.alphagalileo.com/ReadNotice.cfm?releaseid=6925 > > Date Posted : 19 Jul 2001 > Contact Details > Dr Susan Scott, Professor Christopher Duncan > The University of Liverpool > 0151 794 4986/4987 > > [EMAIL PROTECTED] > > Keywords : Books, Life Sciences, Medical, Social Sciences, > > Could the Black Death re-emerge? > > For the whole of the 20th Century it was universally believed that > bubonic plague (a disease of rodents) was responsible for the plagues > that ravaged Europe for over 300 years after the Black Death appeared in > 1347. > > This is completely contrary to the experience of people of that time who > recognised that it was a lethal, infectious disease, spread person-to- > person, and they quickly determined an effective quarantine period. This > medical view persisted until 1900. > > Now, two researchers at the University of Liverpool have shown by > applying modern concepts of epidemiology, molecular biology and computer > modelling to the detailed analysis of historical records that the > causative agent was not a bacterium but a virus with unusual > epidemiological characteristics. > > This piece of interdisciplinary detective work was undertaken by Susan > Scott and Christopher Duncan, of the University's School of Biological > Sciences, and it enabled them to establish the plagues of Europe within > a new geographical, historical and demographic framework. > > The process by which they reached their conclusions is described in the > book "Biology of Plagues" published by Cambridge University Press . The > book also contains a warning that it could happen again. > > "Biology of Plagues": a synopsis. > > Several authors have drawn attention to the potential dangers of lethal > infectious diseases that suddenly emerge, apparently from nowhere, and > threaten our civilisation. Examples are HIV, Ebola and the influenza > pandemic of 1917-19. > > The Black Death arrived in Sicily in 1347 and during the next three > years it spread remorselessly northwards, reaching Norway and crossing > to England and from there to Scotland, Ireland and probably Iceland and > Greenland. The mortality of the pandemic was truly terrible: at least 25 > million people (25-75% of the population) are estimated to have died. It > presaged the age of plagues during which France was continually ravaged, > with several outbreaks in widely separated towns in almost every year. > Infected people travelled to England and other parts of continental > Europe, bringing irregular and devastating epidemics. The age of plagues > in Europe continued for over 300 years until it suddenly and > mysteriously (and thankfully) disappeared in 1670. > > The Black Death was immediately accepted as an infectious disease, > spread person-to-person and the physicians and health authorities of > northern Italy led the world in establishing suitable health measures. > By the late 14th Century they had already identified a 40-day quarantine > period which was strictly maintained throughout Europe for 300 years. A > community knew that it was safe if there had been no plague deaths for > 40 days. Henry VIII decreed that this time should be reduced, but this > decision was speedily reversed when it proved to be completely > ineffective. > > So, the plague was universally accepted for 650 years as an infectious > disease, spread person-to-person until the biology of bubonic plague was > brilliantly elucidated at the end of the 19th Century. It is a bacterial > disease of rodents with a complex biology involving resistant and non- > resistant species and is spread by their fleas. It is endemic in a > variety of rodents across vast areas of Asia today. Occasionally it > spreads to humans via peridomestic rats causing a potentially lethal > disease which is usually treatable with modern medicine. It has been > universally believed, contrary to previous opinion, that bubonic plague > (Yersinia pestis) was also the infectious agent of the plagues that > beset Europe from 1347 to 1670. > > In "Biology of Plagues" Susan Scott and Christopher Duncan detail the > compelling evidence which shows that this view is incorrect. For > example, quarantine measures are completely ineffective against bubonic > plague and the Brown Rat did not arrive in Europe until 50 years after > the plague had disappeared. Indeed, the authors conclude that Yersinia > pestis was the most unlikely candidate for the causative agent of this > disease. > > It was decreed in Elizabethan times that the parish burial registers > should designate those who died of the plague and so medical historians > have invaluable and unique records of the plagues in England over some > 100 years. Scott and Duncan have reconstructed the families in > communities where the plague struck and have shown how the infection > spread through them. The most interesting fact to emerge with complete > consistency is that the time from infection to inevitable death was very > long, some 37-38 days. This was made up of a latent period of 10-12 > days, which was followed by an infectious period (with no overt > symptoms) of 20-22 days, followed by a 5-day period showing symptoms > before death. So, a victim had 32 days to travel by foot, horseback or > sea, carrying a lethal infection that neither he nor anyone else knew > about. The finding confirms the 40-day quarantine period and has been > used in computer modelling to explain why a "typical" plague epidemic in > England lasted 8-9 months. The authors name it haemorrhagic plague to > distinguish it clearly from bubonic plague. > > The HIV virus today enters human white blood cells via a molecular entry > port on the cell surface termed the CCR5 gene product. A mutation of > this gene confers protection against HIV and occurs at high frequency in > Europe, but not in Asia or sub-Saharan Africa. > > Molecular biologists have determined that this mutation probably > appeared about the time of the Black Death and its frequency was then > forced up by the pandemic and by the never-ending series of plague > epidemics in Europe that followed. A rising proportion of the population > slowly became resistant to haemorrhagic plagues in this way. > > What then was the causative agent of haemorrhagic plague? After an > examination of the symptoms (particularly the haemorrhagic red spots on > the chest - "God's tokens") and the primitive autopsy reports of the > dissolution of the internal organs, Scott and Duncan suggest that it may > have been a form of filovirus, distantly related to Ebola. > > Could haemorrhagic plague emerge again? If it did so, infectious > individuals, apparently healthy and not showing any symptoms, would > rapidly spread the disease throughout the world by modern transport > because of the long incubation period. The mortality would be > catastrophic.
