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How was the Black Death stopped?

How was the Black Death stopped?

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I came to understand that the Black Death was transmitted through rats. But I can't find how it ended.

  • Was it the lack of people and a reduction of the trading system between countries that made it less and less present?
  • Did the animal transmitting it become resistent to it?
  • Did we find a cure?

How did it happen?

The answer to this is vast. Simply put, the mix of devastation to the population and the fact that we started to, as @noel1 put it, quarantine people helped. There is also a suspicion that that the bacterium killed off those people that were most susceptible to the plague, leaving those who were naturally immune or in better health. So between reduced contact with others, cleaner living because of less population, natural selection and quarantine, our ancestors lived on.

Scientific American - Black Death survivors and their descendants went on to live longer

Gale - How the Black Death came to an end

History.com - Medieval Black Death was airborne scientists say

To paraphrase history.com the black plague just ran its course and ended by change. However, it reappeared every few generations for quite a while, and eventually, with modern sanitation, it has disappeared almost completely.

Luck and quarantine.
Comes from italian phrase quaranta giorni - forty days for foreign ships to harbour before unloading.

The winter helped kill of fly's that were infected it and reduce the people that were infected. people also died of in the winter which helped halt the black death. Quarantine contributed and as more people died they where less compact which helped.

To prevent the spread of the plague to other towns and villages, Eyam decided to quarantine itself. Two men were responsible for helping the villagers make this momentous decision. One was Eyam&rsquos Anglican vicar, William Mompesson. The other was Thomas Stanley, the former rector. Stanley had been replaced in 1660 by Mompesson&rsquos predecessor because of his Puritan views. However, he continued to live in Eyam. While Stanley and Mompesson&rsquos interpretation of their Christian faith differed, they were united in their purpose to stop the plague.

Mompesson and Stanley ordered the villagers to build a stone perimeter wall half a mile away from the village. No one from within Eyam was allowed to cross the boundary until the settlement was free of plague- even those without symptoms. To ensure that the villagers did not starve, arrangements were made for merchants from local towns and the Earl of Devonshire at nearby Chatsworth House to leave goods and medicine along the southern boundary of Eyam. In return, the villagers paid for goods with coins disinfected in vinegar which they deposited in the hollows of the stone wall.

Stanley and Monpesson were successful in convincing the villagers to observe the quarantine. During the period Eyam was sealed off, only two people tried to leave the village. One, a woman broke quarantine so she could attend the market in the town of Tideswell just five miles away. However, once she arrived at her destination, people recognized her as a resident of Eyam and drove her away with missiles of food and mud and cries of &ldquoThe Plague, The Plague.&rdquo Perhaps the villagers of Eyam did not leave because they knew there was no sanctuary for them in the outside world.

Two Lovers separated by the Quarantine. Detail from Plague Stained Glass window in St Lawrence&rsquos Church, Eyam. Google Images.

Throughout the summer of 1666, conditions in Eyam began to decline. By early August, death was a daily event. As more villagers died, the neglect grew. The fields were left untended and repairs ignored. When the stonemason died, the villagers had to carve their own gravestones. They also had to bury their own dead. One farmer&rsquos wife, Elizabeth Hancock buried her husband and all six of her children in the space of eight days. She was forced to wrap them in shrouds and drag them through the streets by their feet, burying them in the fields that surrounded the village in the area known today as The Riley Graves.

The final death in Eyam was on November 1 st 1666. By this time, out of the 344 villagers, 260 had died. The houses of those wiped out still stand, remembered today as the &ldquoPlague Cottages.&rdquo Each is marked with a green plaque that lists the members of each family lost to the plague. As for those that survived, except for Reverend Monpesson who resigned his living in 1669 and left Eyam never to return, they took up their lives again. Their immunity was due to a plague resistant chromosome, rather than prayer or the smoking of tobacco as was believed at the time. However, they had achieved their objective. Because of Eyam&rsquos sacrifice, the Great Plague spread no further in Derbyshire.

The Black Death: The Greatest Catastrophe Ever

Ole J. Benedictow describes how he calculated that the Black Death killed 50 million people in the 14th century, or 60 per cent of Europe’s entire population.

T he disastrous mortal disease known as the Black Death spread across Europe in the years 1346-53. The frightening name, however, only came several centuries after its visitation (and was probably a mistranslation of the Latin word ‘atra’ meaning both ‘terrible’ and ‘black)’. Chronicles and letters from the time describe the terror wrought by the illness. In Florence, the great Renaissance poet Petrarch was sure that they would not be believed: ‘O happy posterity, who will not experience such abysmal woe and will look upon our testimony as a fable.’ A Florentine chronicler relates that,

All the citizens did little else except to carry dead bodies to be buried [. ] At every church they dug deep pits down to the water-table and thus those who were poor who died during the night were bundled up quickly and thrown into the pit. In the morning when a large number of bodies were found in the pit, they took some earth and shovelled it down on top of them and later others were placed on top of them and then another layer of earth, just as one makes lasagne with layers of pasta and cheese.

The accounts are remarkably similar. The chronicler Agnolo di Tura ‘the Fat’ relates from his Tuscan home town that

. in many places in Siena great pits were dug and piled deep with the multitude of dead [. ] And there were also those who were so sparsely covered with earth that the dogs dragged them forth and devoured many bodies throughout the city.

The tragedy was extraordinary. In the course of just a few months, 60 per cent of Florence’s population died from the plague, and probably the same proportion in Siena. In addition to the bald statistics, we come across profound personal tragedies: Petrarch lost to the Black Death his beloved Laura to whom he wrote his famous love poems Di Tura tells us that ‘I [. ] buried my five children with my own hands’.

The Black Death was an epidemic of bubonic plague, a disease caused by the bacterium Yersinia pestis that circulates among wild rodents where they live in great numbers and density. Such an area is called a ‘plague focus’ or a ‘plague reservoir’. Plague among humans arises when rodents in human habitation, normally black rats, become infected. The black rat, also called the ‘house rat’ and the ‘ship rat’, likes to live close to people, the very quality that makes it dangerous (in contrast, the brown or grey rat prefers to keep its distance in sewers and cellars). Normally, it takes ten to fourteen days before plague has killed off most of a contaminated rat colony, making it difficult for great numbers of fleas gathered on the remaining, but soon- dying, rats to find new hosts. After three days of fasting, hungry rat fleas turn on humans. From the bite site, the contagion drains to a lymph node that consequently swells to form a painful bubo, most often in the groin, on the thigh, in an armpit or on the neck. Hence the name bubonic plague. The infection takes three–five days to incubate in people before they fall ill, and another three–five days before, in 80 per cent of the cases, the victims die. Thus, from the introduction of plague contagion among rats in a human community it takes, on average, twenty-three days before the first person dies.

When, for instance, a stranger called Andrew Hogson died from plague on his arrival in Penrith in 1597, and the next plague case followed twenty-two days later, this corresponded to the first phase of the development of an epidemic of bubonic plague. And Hobson was, of course, not the only fugitive from a plague-stricken town or area arriving in various communities in the region with infective rat fleas in their clothing or luggage. This pattern of spread is called ‘spread by leaps’ or ‘metastatic spread’. Thus, plague soon broke out in other urban and rural centres, from where the disease spread into the villages and townships of the surrounding districts by a similar process of leaps.

In order to become an epidemic the disease must be spread to other rat colonies in the locality and transmitted to inhabitants in the same way. It took some time for people to recognize that a terrible epidemic was breaking out among them and for chroniclers to note this. The timescale varies: in the countryside it took about forty days for realisation to dawn in most towns with a few thousand inhabitants, six to seven weeks in the cities with over 10,000 inhabitants, about seven weeks, and in the few metropolises with over 100,000 inhabitants, as much as eight weeks.

Plague bacteria can break out of the buboes and be carried by the blood stream to the lungs and cause a variant of plague that is spread by contaminated droplets from the cough of patients (pneumonic plague). However, contrary to what is sometimes believed, this form is not contracted easily, spreads normally only episodically or incidentally and constitutes therefore normally only a small fraction of plague cases. It now appears clear that human fleas and lice did not contribute to the spread, at least not significantly. The bloodstream of humans is not invaded by plague bacteria from the buboes, or people die with so few bacteria in the blood that bloodsucking human parasites become insufficiently infected to become infective and spread the disease: the blood of plague-infected rats contains 500-1,000 times more bacteria per unit of measurement than the blood of plague-infected humans.

Importantly, plague was spread considerable distances by rat fleas on ships. Infected ship rats would die, but their fleas would often survive and find new rat hosts wherever they landed. Unlike human fleas, rat fleas are adapted to riding with their hosts they readily also infest clothing of people entering affected houses and ride with them to other houses or localities. This gives plague epidemics a peculiar rhythm and pace of development and a characteristic pattern of dissemination. The fact that plague is transmitted by rat fleas means plague is a disease of the warmer seasons, disappearing during the winter, or at least lose most of their powers of spread. The peculiar seasonal pattern of plague has been observed everywhere and is a systematic feature also of the spread of the Black Death. In the plague history of Norway from the Black Death 1348-49 to the last outbreaks in 1654, comprising over thirty waves of plague, there was never a winter epidemic of plague. Plague is very different from airborne contagious diseases, which are spread directly between people by droplets: these thrive in cold weather.

This conspicuous feature constitutes proof that the Black Death and plague in general is an insect-borne disease. Cambridge historian John Hatcher has noted that there is ‘a remarkable transformation in the seasonal pattern of mortality in England after 1348’: whilst before the Black Death the heaviest mortality was in the winter months, in the following century it was heaviest in the period from late July to late September. He points out that this strongly indicates that the ‘transformation was caused by the virulence of bubonic plague’.

Another very characteristic feature of the Black Death and plague epidemics in general, both in the past and in the great outbreaks in the early twentieth century, reflects their basis in rats and rat fleas: much higher proportions of inhabitants contract plague and die from it in the countryside than in urban centres. In the case of English plague history, this feature has been underlined by Oxford historian Paul Slack. When around 90 per cent of the population lived in the countryside, only a disease with this property combined with extreme lethal powers could cause the exceptional mortality of the Black Death and of many later plague epidemics. All diseases spread by cross-infection between humans, on the contrary, gain increasing powers of spread with increasing density of population and cause highest mortality rates in urban centres.

Lastly it could be mentioned that scholars have succeeded in extracting genetic evidence of the causal agent of bubonic plague, the DNA-code of Yersinia pestis, from several plague burials in French cemeteries from the period 1348-1590.

It used to be thought that the Black Death originated in China, but new research shows that it began in the spring of 1346 in the steppe region, where a plague reservoir stretches from the north-western shores of the Caspian Sea into southern Russia. People occasionally contract plague there even today. Two contemporary chroniclers identify the estuary of the river Don where it flows into the Sea of Azov as the area of the original outbreak, but this could be mere hearsay, and it is possible that it started elsewhere, perhaps in the area of the estuary of the river Volga on the Caspian Sea. At the time, this area was under the rule of the Mongol khanate of the Golden Horde. Some decades earlier the Mongol khanate had converted to Islam and the presence of Christians, or trade with them, was no longer tolerated. As a result the Silk Road caravan routes between China and Europe were cut off. For the same reason the Black Death did not spread from the east through Russia towards western Europe, but stopped abruptly on the Mongol border with the Russian principalities. As a result, Russia which might have become the Black Death’s first European conquest, in fact was its last, and was invaded by the disease not from the east but from the west.

The epidemic in fact began with an attack that the Mongols launched on the Italian merchants’ last trading station in the region, Kaffa (today Feodosiya) in the Crimea. In the autumn of 1346, plague broke out among the besiegers and from them penetrated into the town. When spring arrived, the Italians fled on their ships. And the Black Death slipped unnoticed on board and sailed with them.

The extent of the contagious power of the Black Death has been almost mystifying. The central explanation lies within characteristic features of medieval society in a dynamic phase of modernisation heralding the transformation from a medieval to early modern European society. Early industrial market-economic and capitalistic developments had advanced more than is often assumed, especially in northern Italy and Flanders. New, larger types of ship carried great quantities of goods over extensive trade networks that linked Venice and Genoa with Constantinople and the Crimea, Alexandria and Tunis, London and Bruges. In London and Bruges the Italian trading system was linked to the busy shipping lines of the German Hanseatic League in the Nordic countries and the Baltic area, with large broad-bellied ships called cogs. This system for long-distance trade was supplemented by a web of lively short and medium-distance trade that bound together populations all over the Old World.

The strong increase in population in Europe in the High Middle Ages (1050-1300) meant that the prevailing agricultural technology was inadequate for further expansion. To accommodate the growth, forests were cleared and mountain villages settled wherever it was possible for people to eke out a living. People had to opt for a more one-sided husbandry, particularly in animals, to create a surplus that could be traded for staples such as salt and iron, grain or flour. These settlements operated within a busy trading network running from coasts to mountain villages. And with tradesmen and goods, contagious diseases reached even the most remote and isolated hamlets.

In this early phase of modernisation, Europe was also on the way to ‘the golden age of bacteria’, when there was a great increase in epidemic diseases caused by increases in population density and in trade and transport while knowledge of the nature of epidemics, and therefore the ability to organise efficient countermeasures to them, was still minimal. Most people believed plague and mass illness to be a punishment from God for their sins. They responded with religious penitential acts aimed at tempering the Lord’s wrath, or with passivity and fatalism: it was a sin to try to avoid God’s will.

Much new can be said on the Black Death’s patterns of territorial spread. Of particular importance was the sudden appearance of the plague over vast distances, due to its rapid transportation by ship. Ships travelled at an average speed of around 40km a day which today seems quite slow. However, this speed meant that the Black Death easily moved 600km in a fortnight by ship: spreading, in contemporary terms, with astonishing speed and unpredictability. By land, the average spread was much slower: up to 2km per day along the busiest highways or roads and about 0.6km per day along secondary lines of communication.

As already noted, the pace of spread slowed strongly during the winter and stopped completely in mountain areas such as the Alps and the northerly parts of Europe. Yet, the Black Death often rapidly established two or more fronts and conquered countries by advancing from various quarters.

Italian ships from Kaffa arrived in Constantinople in May 1347 with the Black Death on board. The epidemic broke loose in early July. In North Africa and the Middle East, it started around September 1st, having arrived in Alexandria with ship transport from Constantinople. Its spread from Constantinople to European Mediterranean commercial hubs also started in the autumn of 1347. It reached Marseilles by about the second week of September, probably with a ship from the city. Then the Italian merchants appear to have left Constantinople several months later and arrived in their home towns of Genoa and Venice with plague on board, some time in November. On their way home, ships from Genoa also contaminated Florence’s seaport city of Pisa. The spread out of Pisa is characterized by a number of metastatic leaps. These great commercial cities also functioned as bridgeheads from where the disease conquered Europe.

In Mediterranean Europe, Marseilles functioned as the first great centre of spread. The relatively rapid advance both northwards up the Rhône valley to Lyons and south-westwards along the coasts towards Spain – in chilly months with relatively little shipping activity – is striking. As early as March 1348, both Lyon’s and Spain’s Mediterranean coasts were under attack.

En route to Spain, the Black Death also struck out from the city of Narbonne north-westwards along the main road to the commercial centre of Bordeaux on the Atlantic coast, which by the end of March had become a critical new centre of spread. Around April 20th, a ship from Bordeaux must have arrived in La Coruña in northwestern Spain a couple of weeks later another ship from there let loose the plague in Navarre in northeastern Spain. Thus, two northern plague fronts were opened less than two months after the disease had invaded southern Spain.

Another plague ship sailed from Bordeaux, northwards to Rouen in Normandy where it arrived at the end of April. There, in June, a further plague front moved westwards towards Brittany, south-eastwards towards Paris and northwards in the direction of the Low Countries.

Yet another ship bearing plague left Bordeaux a few weeks later and arrived around May 8th, in the southern English town of Melcombe Regis, part of present-day Weymouth in Dorset: the epidemic broke out shortly before June 24th. The significance of ships in the rapid transmission of contagion is underscored by the fact that at the time the Black Death landed in Weymouth it was still in an early phase in Italy. From Weymouth, the Black Death spread not only inland, but also in new metastatic leaps by ships, which in some cases must have travelled earlier than the recognized outbreaks of the epidemic: Bristol was contaminated in June, as were the coastal towns of the Pale in Ireland London was contaminated in early August since the epidemic outbreak drew comment at the end of September. Commercial seaport towns like Colchester and Harwich must have been contaminated at about the same time. From these the Black Death spread inland. It is now also clear that the whole of England was conquered in the course of 1349 because, in the late autumn of 1348, ship transport opened a northern front in England for the Black Death, apparently in Grimsby.

The early arrival of the Black Death in England and the rapid spread to its southeastern regions shaped much of the pattern of spread in Northern Europe. The plague must have arrived in Oslo in the autumn of 1348, and must have come with a ship from south-eastern England, which had lively commercial contacts with Norway. The outbreak of the Black Death in Norway took place before the disease had managed to penetrate southern Germany, again illustrating the great importance of transportation by ship and the relative slowness of spread by land. The outbreak in Oslo was soon stopped by the advent of winter weather, but it broke out again in the early spring. Soon it spread out of Oslo along the main roads inland and on both sides of the Oslofjord. Another independent introduction of contagion occurred in early July 1349 in the town of Bergen it arrived in a ship from England, probably from King’s Lynn. The opening of the second plague front was the reason that all Norway could be conquered in the course of 1349. It disappeared completely with the advent of winter, the last victims died at the turn of the year.

The early dissemination of the Black Death to Oslo, which prepared the ground for a full outbreak in early spring, had great significance for the pace and pattern of the Black Death’s further conquest of Northern Europe. Again ship transport played a crucial role, this time primarily by Hanseatic ships fleeing homewards from their trading station in Oslo with goods acquired during the winter. On their way the seaport of Halmstad close to the Sound was apparently contaminated in early July. This was the starting point for the plague’s conquest of Denmark and Sweden, which was followed by several other independent introductions of plague contagion later by the end of 1350 most of these territories had been ravaged.

However, the voyage homewards to the Hanseatic cities on the Baltic Sea had started significantly earlier. The outbreak of the Black Death in the Prussian town of Elbing (today the Polish town of Elblag) on August 24th, 1349, was a new milestone in the history of the Black Death. A ship that left Oslo at the beginning of June would probably sail through the Sound around June 20th and reach Elbing in the second half of July, in time to unleash an epidemic outbreak around August 24th. Other ships that returned at the end of the shipping season in the autumn from the trading stations in Oslo or Bergen, brought the Black Death to a number of other Hanseatic cities both on the Baltic Sea and the North Sea. The advent of winter stopped the outbreaks initially as had happened elsewhere, but contagion was spread with goods to commercial towns and cities deep into northern Germany. In the spring of 1350, a northern German plague front was formed that spread southwards and met the plague front which in the summer of 1349 had formed in southern Germany with importation of contagion from Austria and Switzerland.

Napoleon did not succeed in conquering Russia. Hitler did not succeed. But the Black Death did. It entered the territory of the city state of Novgorod in the late autumn of 1351 and reached the town of Pskov just before the winter set in and temporarily suppressed the epidemic thus the full outbreak did not start until the early spring of 1352. In Novgorod itself, the Black Death broke out in mid-August. In 1353, Moscow was ravaged, and the disease also reached the border with the Golden Horde, this time from the west, where it petered out. Poland was invaded by epidemic forces coming both from Elbing and from the northern German plague front and, apparently, from the south by contagion coming across the border from Slovakia via Hungary.

Iceland and Finland are the only regions that, we know with certainty, avoided the Black Death because they had tiny populations with minimal contact abroad. It seems unlikely that any other region was so lucky.

How many people were affected? Knowledge of general mortality is crucial to all discussions of the social and historical impact of the plague. Studies of mortality among ordinary populations are far more useful, therefore, than studies of special social groups, whether monastic communities, parish priests or social elites. Because around 90 per cent of Europe’s population lived in the countryside, rural studies of mortality are much more important than urban ones.

Researchers generally used to agree that the Black Death swept away 20-30 per cent of Europe’s population. However, up to 1960 there were only a few studies of mortality among ordinary people, so the basis for this assessment was weak. From 1960, a great number of mortality studies from various parts of Europe were published. These have been collated and it is now clear that the earlier estimates of mortality need to be doubled. No suitable sources for the study of mortality have been found in the Muslim countries that were ravaged.

The mortality data available reflects the special nature of medieval registrations of populations. In a couple of cases, the sources are real censuses recording all members of the population, including women and children. However, most of the sources are tax registers and manorial registers recording households in the form of the names of the householders. Some registers aimed at recording all households, also the poor and destitute classes who did not pay taxes or rents, but the majority recorded only householders who paid tax to the town or land rent to the lord of the manor. This means that they overwhelmingly registered the better-off adult men of the population, who for reasons of age, gender and economic status had lower mortality rates in plague epidemics than the general population. According to the extant complete registers of all households, the rent or tax-paying classes constituted about half the population both in the towns and in the countryside, the other half were too poor. Registers that yield information on both halves of the populations indicate that mortality among the poor was 5-6 per cent higher. This means that in the majority of cases when registers only record the better-off half of the adult male population, mortality among the adult male population as a whole can be deduced by adding 2.5-3 per cent.

Another fact to consider is that in households where the householder survived, other members often died. For various reasons women and children suffer higher incidence of mortality from plague than adult men. A couple of censuses produced by city states in Tuscany in order to establish the need for grain or salt are still extant. They show that the households were, on average, reduced in the countryside from 4.5 to 4 persons and in urban centres from 4 to 3.5 persons. All medieval sources that permit the study of the size and composition of households among the ordinary population produce similar data, from Italy in southern Europe to England in the west and Norway in northern Europe. This means that the mortality among the registered households as a whole was 11-12.5 per cent higher than among the registered householders.

Detailed study of the mortality data available points to two conspicuous features in relation to the mortality caused by the Black Death: namely the extreme level of mortality caused by the Black Death, and the remarkable similarity or consistency of the level of mortality, from Spain in southern Europe to England in north-western Europe. The data is sufficiently widespread and numerous to make it likely that the Black Death swept away around 60 per cent of Europe’s population. It is generally assumed that the size of Europe’s population at the time was around 80 million. This implies that that around 50 million people died in the Black Death. This is a truly mind-boggling statistic. It overshadows the horrors of the Second World War, and is twice the number murdered by Stalin’s regime in the Soviet Union. As a proportion of the population that lost their lives, the Black Death caused unrivalled mortality.

This dramatic fall in Europe’s population became a lasting and characteristic feature of late medieval society, as subsequent plague epidemics swept away all tendencies of population growth. Inevitably it had an enormous impact on European society and greatly affected the dynamics of change and development from the medieval to Early Modern period. A historical turning point, as well as a vast human tragedy, the Black Death of 1346-53 is unparalleled in human history.

Ole J. Benedictow is Emeritus Professor of History at the Universtiy of Oslo, Norway.

3. The Great Plague of London—Sealing Up the Sick

Scenes in the streets of London during the Great Plague of 1665.

The Print Collector/Getty Images

London never really caught a break after the Black Death. The plague resurfaced roughly every 10 years from 1348 to 1665� outbreaks in just over 300 years. And with each new plague epidemic, 20 percent of the men, women and children living in the British capital were killed.

By the early 1500s, England imposed the first laws to separate and isolate the sick. Homes stricken by plague were marked with a bale of hay strung to a pole outside. If you had infected family members, you had to carry a white pole when you went out in public. Cats and dogs were believed to carry the disease, so there was a wholesale massacre of hundreds of thousands of animals.

The Great Plague of 1665 was the last and one of the worst of the centuries-long outbreaks, killing 100,000 Londoners in just seven months. All public entertainment was banned and victims were forcibly shut into their homes to prevent the spread of the disease. Red crosses were painted on their doors along with a plea for forgiveness: “Lord have mercy upon us.”

As cruel as it was to shut up the sick in their homes and bury the dead in mass graves, it may have been the only way to bring the last great plague outbreak to an end.

Disease Pathway

The oriental flea sucks the blood from an infected rat. The bacterium walls off an area in the flea’s digestive tract preventing the flea from digesting its blood meal. When the rat sucumbs to the plague, the starving flea leaves its furry host to find a meal in humans instead. When the flea bites into human flesh it regurgitates Y. pestis into the open wound transmitting it to its human host..

How the Plague Spread

Most historians think the source for bubonic plague originated in the remote grasslands of Centra Asia . Wild rodents there infected with Y. pestis (along with their flea parasites) migrated to nearby villages after some natural disaster disturbed their food supply. They eventually spread the bacterium to colonies of black rats living in more established cities and towns.

The first known plague pandemic occurred in Egypt in 541 during Emperor Justinian’s rule and is said to have helped bring down the Byzantine Empire. No one knows how many died but early writings account the dead were so numerous they had to be thrown in mass graves. By the late 1330s it trickled out of Central Asia and headed east to China via the Silk Road trade route. Plague carrying rats stowed away on ships headed for Europe infecting crew members whom spread the illness to families and communities in the Italian port cities of Genoa and Florence. The sick rats fled the ships and infected city rodent populations. By 1346 the second pandemic of the plague had begun.

How people lived contributed to the plague’s spread. The mud and twig roofs in peasants homes made an ideal nesting area for rats . People shared living quarters with their animals which provided more hosts for fleas. Regular bathing or laundering of bedding or clothing was uncustomary so fleas thrived on the body and in one’s personal belongings.

Early efforts to contain the plague by quarantining the sick and burning the dead proved ineffective. Some people became shut-ins hoping to outlast the plague while others fled infected villages in an attempt to outrun it. Infection from the plague meant a sure and swift death with no hope for treatment in sight

The Black Death is dead (thanks to evolution)

Evolution tells us a lot about death. Of course it's about life too, but it's really about survival, which involves both life and death.

As most people know, the Black Death was a horrible plague that swept through Europe, Asia, and Africa in the 1300's, killing tens of millions of people at a time when there weren't so many people to begin with. The world's population prior to the plague, about 450 million, dropped to 350 million. About one-third of the entire population of Europe, and half the population of China, may have died. Centuries earlier, the Plague of Justinian in 541-542 C.E. may have killed even more, up to half of Europe and untold millions elsewhere around the world. In ancient and medieval times, people thought the plague was caused by rats, but the true cause wasn't discovered until 1894, when Alexandre Yersin of France and Kitasato Shibasaburo of Japan finally traced it to a bacterium now called Yersinia pestis, which is transmitted by fleas, which in turn are carried around by rats.

The plague kills all of its hosts, even the fleas:

"The bacteria multiply inside the flea, sticking together to form a plug that blocks its stomach and causes it to starve. The flea then bites a host and continues to feed, even though it cannot quell its hunger, and consequently the flea vomits blood tainted with the bacteria back into the bite wound. The bubonic plague bacterium then infects a new victim, and the flea eventually dies from starvation. " Source: Wikipedia

Gross, I know. But the original plague, the Black Death, has never returned. Why not? A study last year and another one published just this week provide the answer.

Last year, Barbara Bramanti and colleagues collected DNA from mass graves dating to the Black Death, and showed conclusively that the victims were infected with Yersinia pestis. Until this study, some scientists were uncertain about whether Yersinia pestis was the true cause, but Bramanti's research should settle that question once and for all. They also showed that at least two distinct strains of plague bacteria infected Europe, each arriving via a different route.

Further evidence appears in a remarkable new study published this week by Hendrik Poinar and colleagues. They exhumed over 100 skeletal remains from victims of the Black Death, collected from a ancient London cemetery, East Smithfield, which has been conclusively dated to the plague years, 1348-1350. Using the latest DNA sequencing methods, they identified Yersinia pestis DNA in 20 of the 109 victims.

Both studies collected enough DNA to show that the strain of Yersinia pestis from 1350 C.E. is unlike any modern strain. In other words, the original plague died out, probably long ago. The likely explanation is just this: the Black Death was simply too deadly to persist. Evolutionary theory tells us that a pathogen that kills all its victims will eventually run out of victims, leading to its own extinction. The plague bacteria needed to evolve into something less virulent, and that seems to be what happened. A bug that doesn't kill its host is far more successful evolutionarily. (Just look at the common cold, which we can't seem to get rid of.)

The same thing happened to the "Spanish" flu virus, the one that cause the terrible 1918 flu pandemic. It too evolved into a milder pathogen, and it is still with us today - the 2009 influenza pandemic was caused by a direct descendant of the 1918 virus.

The Black Death was so widespread that it even affected human evolution. In 1998, Stephen O'Brien and colleagues showed that a mutation that confers resistance to HIV first appeared in the human population in the 1300's. They concluded that this mutation can best be explained by "a widespread fatal epidemic" in other words, the Black Death. I should be careful to explain that the plague didn't actually cause the mutation: the mutation occurred naturally. The Black Death selectively killed more people without the mutation, leaving us with a population of humans that tended to have the mutation.

Why did the black death just stop?

I know there are still a handful of cases that happen each year, but for the most part the plague just seemed to disappear. Why hasn't this also happened with other diseases like the common cold?

Improved hygiene and sanitation conditions probably helped out immensely with reducing disease spread. Moreover not everyone would die of the plague, especially those with mutation that makes them immune against HIV (a very small population).

The cold virus also mutates at a much faster rate than the plague which is why we can't vaccinate against all the strains that are possibly generated.

Moreover not everyone would die of the plague, especially those with mutation that makes them immune against HIV (a very small population).

This is actually not believed to be the case anymore. Currently, the evidence is more in favor of smallpox as the causative factor for the selection of the CCR5-Δ32 allele.

The CCR5-Δ32 mutation confers no protection against Y. pestis-induced mortality or bacterial load in mice. Unless our immune system is significantly different in its functions from that of a mouse (it isn't), it's highly unlikely this allele provides any protection to the black death. This paper argues that the selective pressure from the black death was not strong enough to explain the current prevalence of the allele in European populations, and models the effects of sporadic epidemics (smallpox) versus large-scale cullings (such as the Black Death), and rule in favor of the sporadic (but also very frequent) outbreaks as a stronger selection factor for the allele.

especially those with mutation that makes them immune against HIV (a very small population).

Can you elaborate on this? I read the page but would the HIV resistance help with other diseases, namely the black plague? I don't know so much about immunology but it would be understandable if the diseases functioned similarly.

There are a few reasons the Black Death was so terrible when it was. The populations at the time were the children of parents who experienced famine which weakens the immune system. Also the climate was experiencing cooling and winters were serve which may have led to animals being kept indoors to keep the main source of resources alive. Unfortunately this also meant that disease carrying fleas had easy access to humans. The disease itself wasn't particularly lethal. It was a combined factor of terrible living conditions of the time and that many families would abandon the sick and leave them to fend for themselves. Once medicine was able to catch up, the bubonic plague was not as much of an issue. The common cold on the other hand is a virus that reproduces quickly enough that even though our bodies produce antibodies by the time you get the cold again the virus will be mutated enough that the antibodies aren't effective. It's the same reason why it's difficult to vaccinate.

The common cold is a collection of around 200 or so different viruses that target the same thing. That's why it can't be cured. It's pretty harmless, but the one your body fights off won't be the same as the one I get.

The common cold is a collection of around 200 or so different viruses that target the same thing.

Does that put a limit on the number of times you can get the cold in a lifetime?

If you don't get an answer here, you can try r/askhistorians.

Plague stopped because its basic reproduction number fell below 1. This occurred because when plague is in the pneumonic form (spread through the air) it is highly lethal thus the death of almost 1/3 of region ultimately the disease killed so many people and there was such a stigma associated with it that it was unable to sustain the outbreak until more hosts were available (rats and people).

As has been mentioned the "common cold" is highly mutagenic and also many types of viruses are responsible for the general symptoms. The colds do in fact burn themselves out in a similar manner though we develop immunity vs just dying off.

Don't forget natural immunity should also play a huge role in reproduction ratio, not just deaths / population density.

The combined immune system response in the population responding has the same effect at the end of the day as vaccination campaigns, just. a bit more costly.

I'm basing my fact off of research and what I learned in world history. So I'll be saying the history aspect. Basically they grew immunities, and stuff like fountains and such were built, giving access to water for sanitation to the public. But they still carried the pathogen, so when they brought it to places, like, the new world, it spread because they had little to no hygiene and weren't immune

The bubonic plague bacterium is carried by fleas, which themselves are carried by rodents. Back during the Black Death you probably had more rodents in your hovel than humans, and so contact with the flea vector was much more prevalent. These days, not so much. Also, we now have antibiotics that makes the disease much less likely to kill the victim.

The cold virus is much easier to spread as it can become airborne and can persist on surfaces. If there is high enough population density it is very communicable and near impossible to completely eradicate.

This doesn't answer the question at all. Antibiotics were discovered som 600 years after the black plague ended.

The black death ended because the bacterium that caused it died out. The modern plague descends from a different line of the bacterium, which is less aggressive.

Both the common influenza and the plague are originally animal diseases, that at one point made a mutation to be able to infect humans. It is neither for a bacterium nor a virus a beneficial trait to kill its host (. too fast) as that limits its possibilities to reproduce further, therefore diseases usually become less deadly if they have some time to adjust to a new host. Diseases that just made this transition to humans recently can be extremely deadly, as they are not well adjusted to humans, nor is the human immune system adjusted to resist them. One example for such a recent transitions are the influenza pandemics from 1917 and 1958. Both where extremely deadly in the first year they showed up, but soon after, the most aggressive strains of the disease died out as they had killed all their hosts and the less aggressive stains got into a certain balance of power with the humans immune system, which allowed most victims to survive and continue to spread the disease at a such low rate that, on average, a person that got the disease once lost its immunity again when it got reinfected. This allowed such strains to survive within the human population.

When the black death first showed up, it was so infectious that it infected nearly all the globe within a couple of years. It nearly infected all inhabitants of a certain region nearly at the same time. That meant, that soon all potential hosts within the reach of a given host of the bacterium where either dead or already had survived the plague and build up immunities. Therefore the bacterium could not spread any further in the time the host needed to either die or build up immunities. It only survived in some corners of the civilisation, where the spread was slowed down by low rates of contact between hosts (read: low population density). On top of that the shock from the black death on medieval societies was so strong that soon afterwards radical measurements where taken to avoid the spread of such diseases, namely the quarantine, which proved actually as fairly effective in limiting further outbreaks of the plague. The strain of the bacteria responsible for the black death died out.

Modern cases of plague are caused by a strain of the bacteria that made the transition to humans in the 19th century in India and is apparently less infectious as the original black death. On top of that "modern" methods in dealing with diseases managed to limit the outbreak to mostly India. However, the slower rate of infection and the lower lethality means that the bacterium can survive quite long in a given human population and is therefore a pain to eradicate even with antibiotics, especially in a country with the hygiene standards of India.

Effects and consequences

The disease had a terrible impact. Generally speaking, a quarter of the population was wiped out, but in local settlements often half of the population was exterminated.

The direct impacts on economy and society were basically a reduction in production and in consumption. The epidemic clearly caused economic effects which brought about the deepest ever recession in history. It is important to note that it is in this era, so clearly marked by the impact of the plague, when the large-scale construction of monasteries, churches and cathedrals peters out. Consequently, it can be said that the black death is the reason the Middle Ages come to an end.

In the short, the most noteworthy economic consequences of the disease were that the fields were not cultivated and the harvests rotted this in turn sparked an incipient shortage of agricultural products, which were only consumed by those people who could pay for them. With the increase in prices, those with the fewest means endured hardship and suffering.

In the long term, this situation would be aggravated by specific outbreaks of Black Death until the end of the Middle Ages.

How was the Black Death stopped? - History

In the fourteenth century, Europe suffered numerous catastrophes that would go down in history as "The Four Horsemen of the Apocalypse" a reference to the book of Revelation in which four great ordeals which Earth had to endure in its final days before judgement. The Black Death stands out as the most dramatic and lifestyle changing event during this century. This was a widespread epidemic of the Bubonic Plague that passed from Asia and through Europe in the mid fourteenth century. The first signs of the Black Plague in Europe were present around the fall of 1347. In the span of three years, the Black Death killed one third of all the people in Europe. This traumatic population change coming into the Late Middle Ages caused great changes in European culture and lifestyle.

Historical Background

The Black Death was one of many catastrophes to occur following an increase in population during the High Middle Ages (1000-1300). The population of Europe grew from 38 million to 74 million in this time. Prior to the onset of the fourteenth century turmoil, Europe seemed to be in a state of growth in both agriculture and structure in society. Cities began to rise with artisans, farmers, and other crafts people specializing in their own field of work. The daily life contact between European people in the cities and surrounding villages facilitated the spread of this disease, as people did not possess sufficient medical knowledge to prevent the spread of the disease with any great success. The conditions in the cities also set the stage for disease. Waste accumulated in the streets for lack of sewer systems. Houses were crowded next to each other. One could not use the rivers for drinking water due to pollution. With all of these conditions arising from the High Middle Ages, it was only a matter of time before the population was curbed by disaster. The Black Death marks the barrier between the High Middle Ages and the Late Middle Ages, and the difference in Europe before and after the Black Death is clear.

The origins of the Black Death can be traced back to the Gobi Desert of Mongolia in the 1320s. The cause of this sudden eruption of the plague is not exactly known. From the desert, it spread out in all directions. Of most importance was the spread eastward to China. China suffered an emergence of bubonic plague during the early 1330s. During the expansion of trade during the Early and High Middle ages, trade routes with China were strengthened and ventured greatly. European traders, particularly those from the Italian city states, traveled the Black Sea region regularly. Surviving documents show that one group of traders from Genoa arrived in Sicily In October of 1347, fresh from a voyage to China. This was most likely the introduction of the plague to European lands. Along with the Chinese goods on board, the traders carried the bacterium yersinia pestis in the rats on board as well as in some of the sailors themselves. The Black Death had arrived in Europe.

From Sicily, the plague spread at an alarming rate. The speed at which it spread and killed, as well as the horror which accompanied the diseased, caused a panic in the Italian population. Families were forced to abandon members who were sick. Lawyers refused to form wills for the dying. Entire monasteries were wiped out when they attempted to care for the dying, which caused great fear in charitable organizations. Other European countries looked toward Italians as being the cause of the plague, and there were many incidences of healthy Italian travelers and traders being exiled from villages or even killed out of fear of the plague spreading outside Italy. These measures proved futile, and the plague spread farther and farther north. Wherever trade routes existed, normally the plague would follow, radiating out from Italy. The Plague reached France shortly after Italy. Marseilles felt the effects in January of 1348 and Paris was infected in summer of the same year. England felt the effects in September of 1348. 1348 Europe suffered the most. By the end of 1348, Germany, France, England, Italy, and the low countries had all felt the plague. Norway was infected in 1349, and Eastern European countries began to fall victim during the early 1350s. Russia felt the effects later in 1351. By the end of this circular path around Europe, one third of all people in the infected areas had perished.

The people of Europe did not know that such a calamity was the result of a microscopic bacillus bacterium. This organism was not new to the world in the fourteenth century, it had existed for millions of years prior. Europe actually had already felt a blow from the same plague earlier in the 6th century. The emergence at this particular time has unknown causes, yet some speculate that the "mini ice age", a climatic change felt in Europe prior to the Black Death, may have served in the process. Rodents are very susceptible to infection from the bacteria, especially common rats. These rats are also host to parasitic fleas, which live off of the blood of other animals. The flea is not affected by the bacterium, yet still carries it in the blood extracted from the rat host in its digestive tract. The flea's ability to carry the disease without death makes it a perfect conduit of transfer from organism to organism. When these rats inhabit urban areas or boats in order to live off of stored food supplies, they bring the fleas with them. Fleas leave the rat, which also dies shortly from the disease, and moves on to a new host humans.

Once the flea bites a human, infected blood from the rat is introduced to the healthy blood of the human, and the bacteria spreads. Death occurs in less than a week for humans. A high fever, aching limbs, and fatigue mark the early stages of infection. Eventually, the lymph nodes of the neck, groin, and armpit areas swell and turn black. Those black swellings on victims are what give the Black Death its name. The victim begins to vomit blood and in some instances suffer hysteria from fever and terror. Exposure to any body fluids means exposure to the bacterium, and thus spreading the disease is very easy through coughing victims. The victim dies shortly after the lymph nodes swell until bursting within the body. Within a European village, by the time the initial carrier of the disease had perished, the disease would have already taken early stages in several other individuals, making prevention extreamly difficult.

The cycles of the seasons corresponded to cycles of infection. As winter approached, colder temperatures killed fleas and caused rats to seek dormancy. This gave the false appearance of an "all clear" in areas that had been ravaged by plague the previous summer. The disease was not gone, it was simply dormant for a few months. Europe was then taken by surprise with new outbreaks in new areas as temperatures again made for a hospitable environment for flea and rat populations.

The idea that the Black Death was solely caused by the bubonic strain of plague has been questioned. The bubonic plague is actually the weakest strain of known plagues. The other two strains are the septicaemic plague, which infects the circulatory system in victims, and the pneumonic plague, which infects the respiratory system. The fact that accounts from the time indicate that the Black Death killed virtually all infected people raises doubt. The bubonic plague is not as fatal compared to the other two strains (which have mortality rates close to 100%). The consideration to make is that malnutrition plays a major role in the furthering of the consequences of infection. Those groups most ravaged by the Black Death had already suffered from famine earlier in the fourteenth century as storms and drought caused crop failures. These malnourished peasants fell victim with little resistance from their weak immune systems.

Most first hand written accounts that are present today read like this one from the site of the first plague cases in Italy, Messina: "Here not only the "burn blisters" appeared, but there developed gland boils on the groin, the thighs, the arms, or on the neck. At first these were of the size of a hazel nut, and developed accompanied by violent shivering fits, which soon rendered those attacked so weak that they could not stand up, but were forced to lie in their beds consumed by violent fever. Soon the boils grew to the size of a walnut, then to that of a hen's egg or a goose's egg, and they were exceedingly painful, and irritated the body, causing the sufferer to vomit blood. The sickness lasted three days, and on the fourth, at the latest, the patient succumbed". The Italian writer Giovanni Boccaccio wrote graphically about the Black Death in The Decameron. He describes how "More wretched still were the circumstances of the common people and , for a great part, of the middle class, for, confined to their homes either by hope of safety or by poverty, and restricted to their own sections, they fell sick daily by thousands. There, devoid of help, or care, they dies almost without redemption. A great many breathed their last in the public streets, day and night a large number perished in their homes, and it was only by the stench of their decaying bodies that they proclaimed their death to their neighbors. Everywhere the city was teeming with corpses. "

When the plague first entered an area, mourners of the deceased still prepared coffins and conducted ceremonies for their loved ones. Within weeks, in response to desperation to control the sickness as well as sheer volume of the dead, officials had to resort to mass graves. There was not nearly enough consecrated ground for each victim to have an individual plot, and so enormous trenches were dug into which layer upon layer of dead bodies were lain. The trench was topped off with a small layer of soil, and the morbid process continued. Pope Clement VI even consecrated the entire Rhone river so that corpses could be thrown into it for lack of earth. Those in the peasant class who saw horrors such as these could not accept that a loving God could inflict such a plague upon His people, and considered it to be a punishment from an angry God. Some peasants resorted to magic spells, charms, and talismans. Some people burned incense or other herbs as they believed that they overpowering smell of the dead victims was the source of the disease. Some people even tried to "drive the disease away" with sound from church bells and canon fire. Jews were easy targets for people to blame, and numerous instances of Jew persecution and execution occured. Churchmen, and public officials considered the disease to be just that a disease. They took measures to quarantine the infection by walling up homes that had members with disease. In Venice and Milan, ships coming in from areas in which disease had been rampant were diverted to separate islands. This action had limited success, but still prevented the disease more than in other areas which did not enforce this type of quarantine. The wealthy were able to leave infected areas and established residence afar. A rather ingenious method of prevention was taken up by pople Clement VI who sat between two large fires at his home in Avignon. Because excess heat destroys bacterium, he was taking the safest, though slightly ludicrous, measures. In the long run, the only "cure" for this epidemic was time, and it seemed, the shortage of new hosts for the disease.

When the Black Death had finally passed out of Western Europe in 1350, the populations of different regions had been reduced greatly. Some villages of Germany were completely wiped out, while other areas of Germany remained virtually untouched. Italy had been hit the hardest by the plague because of the dense population of merchants and active lifestyle within the city states. For example, the city state of Florence was reduced by 1/3 in population within the first six months of infection. By the end, as much as 75% of the population had perished, which left the economy in shambles. Widespread death was not limited to the lower classes. In Avignon, 1/3 of the cardinals were dead. Overall, 25 million people died in just under five years between 1347 and 1352. It is important to realize that the plague had not entirely vanished, only the primary epidemic. Recurrences of bubonic plague occurred every so often and had a traumatic effect on population even then. The plague did not entire vanish as we know it until the late fifteenth century, which allowed for populations to finally begin to rise to the heights that they were at before the Horseman of Death came to Europe.

Historical Significance

The Black Death brought about great change in attitude, culture, and general lifestyle in Europe. A group of individuals known as the Flagellants traveled from town to town beating themselves and inflicting any other punishment that they believed would help atone for the wrongs that they believed had brought about God's wrath. This group was condemned by Pope Clement VI in 1349 and was crushed soon after. The general morbid attitude of the people following the disaster was shown in Tomb engravings. Instead of the traditional engravings of the enclosed being dressed in armor or fine outfits, now carved images of decaying bodies were present. Paintings of the later fourteenth century also demonstrate morbid obsessions of those who had endured the time of the plague. One of the greatest effects of the Black Death was in the realm of laboring classes. The shortage of labor to work land for landowners created opportunity for those living in areas afar as subsistence farmers. They moved to farming communities and along with already present farming peasants, were able to win better working conditions through negotiating and rebelling against landowners. This set Western Europe along the path of diverging classes. The main theme that one can derive from the Black Death is that mortality is ever present, and humanity is fragile, attitudes that are ever present in Western Nations.

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