- This article concerns the outbreak of the mid-1300s. For detailed information on the most commonly accepted cause of the epidemic, see Bubonic plague.
The Black Death (also The Bubonic Plague, and more recently The Black Plague) was a devastating epidemic in Europe in the 14th century which is estimated to have killed about a third of the population. Although the matter is in dispute, most scientists have generally believed that the Black Death was an outbreak of bubonic plague, a dreaded disease that has spread in pandemic form several times through history. Sometimes, the term "Black Death" is used for all outbreaks of plague and epidemics.
It is believed that the 14th century plague was caused by the bacterium Yersinia pestis which is spread by fleas with the help of animals like the black rat (Rattus rattus) — what we would call today the sewer rat. The possibility for a deadly human illness to be carried by non-human species is due to the many differences between human and non-human anatomy and physiology. Comparative anatomy studies the evolution of the complex morphological systems which make this possible.
Evolution
It is not entirely clear where the major epidemic of the 14th century started, perhaps somewhere around the northern parts of India, but more likely in the steppes of central Asia, from where it was carried west by Mongol armies. The plague was imported to Europe by the way of the Crimea, where the Genoese colony Kaffa (Feodosiya) was besieged by the Mongols. History says that the Mongols catapulted their infected corpses into the city. The refugees from Kaffa then took the plague along to Messina, Genoa and Venice, around the turn of 1347/1348. Some ships didn't have anyone alive when they reached their port. From Italy the disease spread clockwise around Europe, hitting France, Spain, England (in June 1348) and Britain, Germany, Scandinavia and finally north-western Russia around 1351. In 1896, a scientist named Alexander Yersin isolated the plague bacterium and determined that it was spread by fleas and a certain species of rat found in the Gobi Desert.
Consequences
Information about the death toll varies widely from source to source, but it is estimated that about a third of the population of Europe died from the outbreak in the mid-1300s. Approximately 25 million deaths occurred in Europe alone, with many others occurring in Africa and Asia. Recent studies have predicted a decline from twenty-five percent to fifty percent population decrease in Europe alone. Some villages were deserted, the few survivors fleeing and spreading the disease further. Therre is some speculation that the Black Death fatally weakened the Mongol Empire by decimating the Mongols and their conquered peoples, leaving it to fragment and ultimately collapse.
The great population loss brought economic changes based on increased social mobility, as depopulation further eroded the peasants' already-weakened obligations to remain on their traditional holdings. The sudden scarcity of cheap labor provided an incentive for innovation that broke the stagnation of the Dark Ages and, some argue, caused the Renaissance, despite the Renaissance occurring in some areas (such as Italy) before others. However, also because of depopulation, the surviving Europeans became the biggest consumers of meat for a civilization before industrial agriculture.
In many parts of Europe, rumors circulated that the plague was caused by the deliberate poisoning of wells by Jews. Fierce pogroms frequently resulted in the death or banishment of most of the Jews in a town or city.
The reduction in the population of England lead to the displacement of French by English. It has also been alleged (since 1961) that the Black Death inspired one of the most enduring nursery rhymes in the English language, Ring around a rosie, a pocket full of posies, / Ashes, ashes, we all fall down. However, this explanation is a literary interpretation without historical supporting evidence.
See also Danse macabre, Decameron, flagellant, pogrom.
Alternative explanations
Recently the scientists Susan Scott and Christopher Duncan from Liverpool University have proposed the theory that the Black Death might have been caused by an Ebola-like virus, not a bacterium. Their rationale is that this plague spread much faster and the incubation period was much longer than the plagues caused by Yersinia pestis. (A longer period of incubation will allow carriers of the infection to travel farther and infect more people than a shorter one. When the primary vector is humans, as opposed to birds, this is of great importance.) Studies of English church-records indicate an unusually long incubation period in excess of 30 days which could account for the rapid spread, topping at 5 km/day. It also took place in completely ratless areas like Iceland. It was transferred between humans (which happens rarely with Yersinia pestis), and some genes that determine immunity to Ebola-like viruses are much more widespread in Europe than in other parts of the world.
Another alternative explanation was proposed by Graham Twigg in his 1985 book The Black Death: A Biological Reappraisal.
In a similar vein, historian Norman F. Cantor, in his 2001 book In the Wake of the Plague, suggests the Black Death might have been a combination of pandemics including a form of anthrax, a cattle murrain. Included in the evidence he cites are reported disease symptoms not in keeping with the known effects of either bubonic or pneumonic plague; the discovery of anthrax spores in a plague pit in Scotland, and the fact that meat from infected cattle was known to have been sold in many rural English areas prior to the onset of the plague.
Moreover, what was previously considered to be final evidence for the Yersinia pestis theory, tooth pulp tissue taken from a 14th century plague cemetery in Montpellier containing Y. pestis DNA, was never confirmed in any other cemetery.
There are counter-arguments to this theory, however. Historical examples of pandemics of other diseases in populations not previously exposed, such as smallpox and tuberculosis amongst American Indians, show that because there is no inherited adaptation to the disease, its course in the first epidemic is faster and far more virulent than later epidemics amongst the descendants of survivors. The Middle East and Far East were affected equally badly (as the Rihla of Ibn Battuta testifies), so the prevalence of immunity genes specifically in Europeans is curious. Furthermore, the plague returned again and again and was regarded as the same disease through succeeding centuries into modern times when the Yersinia bacterium was identified.
In September 2003, a team of researchers from Oxford University revealed the surprising results of tests made on 121 teeth from 66 skeletons found in 14th century mass graves. The remains showed no genetic trace of Yersinia pestis, and the researchers suggest that the Montpellier study might have been flawed.
External links and references
- Overview of the Black Death with eyewitness accounts
- BBC news story on controversy over Black Death origins
- Mark Derr, "New Theories Link black Death to Ebola-Like Virus", The New York Times, Science Section, October 2, 2001.
- Examination of "Ring around the Rosy"'s relationship to the plague