What caused the Black Death?

Written by C J Duncan, S Scott

 

For the whole of the 20th century it was believed that the Black Death and all the plagues of Europe (1347–1670) were epidemics of bubonic plague.

This review presents evidence that this view is incorrect and that the disease was a viral haemorrhagic fever, characterised by a long incubation period of 32 days, which allowed it to be spread widely even with the limited transport of the Middle Ages.

It is suggested that haemorrhagic plague emerged from its animal host in Ethiopia and struck repeatedly at European/Asian civilisations, before appearing as the Black Death.

Immediately on its arrival in 1347 in the port of Messina in Sicily the Great Pestilence (or Black Death as it was named in 1823 because of the black blotches caused by subcutaneous haemorrhages that appeared on the skin of victims) was recognised as a directly infectious disease.

Michael of Piazza, a Franciscan friar who wrote 10 years after the Black Death had arrived, said “The infection spread to everyone who had any intercourse with the disease”.1 Indeed, they believed (incorrectly) that priests who heard the confessions of the dying “were immediately overcome by death, so that some even remained in the rooms of the dying.”1

Case mortality was 100%. They realised that safety lay in fleeing but this, very effectively, served only to spread the infection.

The Black Death moved as a wave northwards through Europe at an average speed of about 4 km per day and reached the Arctic Circle by 1350, remarkable progress in the days of very limited means of transport.2–4

Even more impressively: it had earlier appeared in Asia Minor and the Crimea and moved south through Antioch; it was present in the Levant and spread along the north African coastlands and to Mecca in Saudi Arabia, covering, in all, some seven million square km.

When it had burnt itself out, 40% of the population of Europe had been killed. This outbreak was a pandemic on a scale never before experienced (or since).

But this unknown disease had not disappeared completely and there were epidemics scattered through Europe during the 1350s.5 Thereafter, the plague was permanently established in France with epidemics every year that cycled round the main trading routes.

From there, infected travellers carried the disease by road and river across the continental landmass and by sea to Britain and Ireland. But all these peripheral epidemics died out completely and were restarted by fresh infectives coming from the focus in France.4

The epidemics progressively increased in spread, frequency, and ferocity (fig 1) with a pronounced rise after 1550 because transport improved and the population of the towns steadily grew (that is, there was a greater number of susceptibles). Contemporary accounts, pattern of spread, and mortality all confirm that the same pathogen was responsible for all the plagues, including the first strike of the Black Death.

Figure 1

 Number of places in Europe reporting a plague epidemic, 1350–1670. Note the increased frequency after 1550. Data from Biraben.5

PUBLIC HEALTH MEASURES

Even in the 14th century the health authorities in northern Italy had established the importance of a 40 day quarantine period, which became the gold standard for continental Europe for the next 300 years. The 40 day quarantine was not adopted in England until the 16th century and even then it was changed to 30 days only to find that this was completely ineffective, whereupon this regulation was speedily rescinded.

The complete success of the quarantine period confirms that the plague was a directly infectious disease and it also shows that it had a long incubation period. Towns in France gradually realised that the danger lay in the arrival of an infected traveller who may well have come from a considerable distance.

Entry was denied if they had come from a town that had suffered an epidemic. Later, in addition to inspecting travellers on arrival, the authorities also required proof that all the towns through which they had journeyed were completely free of plague.

Once an epidemic had erupted, those displaying symptoms were removed to emergency primitive isolation hospitals called pest (an abbreviation of pestilence) houses, which were hurriedly erected outside the town. Once a plague case had been identified, the family was locked up in the house, the well known cross was daubed on the door, and a watchman was appointed to stand guard.

These measures were less successful in containing an epidemic because, as shown below, victims were more infectious before the appearance of the symptoms.

Despite only sketchy medical knowledge at the time, the epidemiology of the plague was fully understood at least by the middle of the 17th century. Daniel Defoe6 had perspicaciously noted that, in the Great Plague of London in 1665, “because of its infectious nature, the disease may be spread by apparently healthy people who harbour the disease but have not yet exhibited the symptoms.

Such a person was in fact a poisoner, a walking destroyer perhaps for a week or a fortnight before his death, who might have ruined those that he would have hazarded his life to save… breathing death upon them, even perhaps his tender kissing and embracings of his own children.”

Clearly, they recognised that victims were infectious before the symptoms appeared, the lengthy duration of the incubation period, the necessity of a 40 day quarantine, and the dangers of droplet infection. But there were many features of the epidemics that were mystifying and they also clung to their beliefs in divine intervention, transmission via contaminated clothing and bedding, movements of the planets, and poisonous miasmas.

Read the full article here.

****

PRINCIPIA SCIENTIFIC INTERNATIONAL, legally registered in the UK as a company incorporated for charitable purposes. Head Office: 27 Old Gloucester Street, London WC1N 3AX. 

Please DONATE TODAY To Help Our Non-Profit Mission To Defend The Scientific Method.

Comments (11)

  • Avatar

    Joseph Olson

    |

    “The Aurelius Pandemic” at DailyStoic(.)com > on TheirTube

    Between 165 AD and 180 AD, over 3% of the Roman Empire died, estimated 10 to 18 million. We live in a Universe that is profoundly indifferent to the existence of life, and are ruled by demonic warlords, who disdain life, with the uncontrolled power to destroy life.

  • Avatar

    tom0mason

    |

    The awful power of nature — it could, in a heartbeat of archaeological time, turn humans — arguably the most successful mammals currently on the planet — to mere fodder for the maggots and worms. And all of our existence, our endeavors, our art, our medical, scientific and technological developments all rendered inconsequential — humanity as mere blip in the history of the planet.

    We never have been and are not now in control of nature. Nature has it’s own chaotic ways and we are not powerful enough to control them because we do not understand the chaotic patterns that are inherent and drive nature.

    • Avatar

      Jerry Krause

      |

      Hi TomO,

      You refer to the chaotic ways of nature. I ask you, or any readers, to list natural phenomena, beside weather phenomena, which are chaotic. I ask you and others to do this because I am curious what natural phenomena might be listed.

      Have a good day, Jerry .

      • Avatar

        tom0mason

        |

        2 for now …
        Plagues, seismic activity,

      • Avatar

        tom0mason

        |

        The exact position of any atomic particle.

      • Avatar

        WhoKoo

        |

        Genetic mutations, including from parents to offspring.

        Animal behaviour, especially in relation to stress and threats or for human animals, tyranny.

        Scientific hypothesis when valid data is ignored.

      • Avatar

        tom0mason

        |

        Maybe Jerry you know the answer to this better than I but is not the actual solar cycle length subjected to chaos.
        Yes on average they are 22 years (2 x 11year periods) but in actuality the cycle rarely lasts exactly that period.

      • Avatar

        Jerry Krause

        |

        Hi TomO and WhoKoo,

        Thank you,

        When I asked I was only considering earth quakes and volcanic erupts. Had to look up solar cycle because I was unfamiliar with them. But in the lack of a precise period I would classify as the result of perturbations and not chaos. Even though i would include sun spots in the list

        But the bottom line might be there are no wrong answers. For each of us maybe has a different idea (definition) of what chaos is because it is chaos.

        Genetic mutations is a good one. As are many diseases.

        Thank you for broadening my horizons

        Have a good day, Jerry.

        .

        • Avatar

          tom0mason

          |

          You say “But in the lack of a precise period I would classify as the result of perturbations and not chaos.” but those perturbations have causes, and those causes comply to physics and mathematics (even if we don not know all the details yet).
          From chaos theory it is the interaction between simple elements (and their underlying math/logical rules) that can give rise to complex chaotic behaviors e.g. your perturbations (perhaps?). See link to the last video referenced below for how simple mathematical/logical rules can generate chaos .

          In my world just about everything has some degree chaos in it.
          Plagues, pandemics, and climate is chaos writ large.

      • Avatar

        tom0mason

        |

        Some videos Jerry …
        BBC video — High Anxieties- The Mathematics of Chaos (2008)
        https://www.youtube.com/watch?v=qfp5tKeSQAc
        ~~~~~~~~
        And …
        Video of Christmas Lectures from 1997 ‘The Magical Maze: Chaos and Cauliflowers’.
        Lecture 4 – Chaos and cauliflowers. From the 1997 DVD companion: For mathematicians, there is order to be found everywhere, even in disorder. Professor Stewart sets out to do what man has attempted since the dawn of time …
        https://www.rigb.org/christmas-lectures/watch/1997/the-magical-maze/chaos-and-cauliflowers

  • Avatar

    tom0mason

    |

    Also Jerry any natural process that involves fractals to any degree has chaotic elements within it.

Comments are closed