SUMMARY. Plague is an infectious disease caused by the bacterium Yersinia pestis. Symptoms include fever, weakness and headache. Usually, this begins one to seven days after exposure. In the bubonic form, there is also swelling of lymph nodes, while in the septicemic form tissues may turn black and die, and in the pneumonic form shortness of breath, cough and chest pain may occur.
Bubonic and septicemic plague is generally spread by flea bites or by handling an infected animal. The pneumonitic form is generally spread between people through the air via infectious droplets. Diagnosis is typically by finding the bacterium in fluid from a lymph node, blood or sputum.
Globally about 600 cases are reported a year. In 2017 the countries with the most cases include the Democratic Republic of the Congo, Madagascar and Peru. In the United States infections usually occur in rural areas. It has historically occurred in large outbreaks, with the most well-known being the Black Death in the 14th century, which resulted in more than 50 million deaths.
TYPES of INFECTION
Bubonic Plague. When a flea bites a human and contaminates the wound with regurgitated blood, the plague-carrying bacteria are passed into the tissue. Y. pestis can reproduce inside cells, so even if phagocytosed, they can still survive. Once in the body, the bacteria can enter the lymphatic system, which drains interstitial fluid. Plague bacteria secrete several toxins, one of which is known to cause beta-adrenergic blockade. Yersinia pestis spreads through the lymphatic vessels of the infected human until it reaches a lymph node, where it causes acute lymphadenitis. The swollen lymph nodes form the characteristic buboes associated with the disease, and autopsies of these buboes have revealed them to be mostly hemorrhagic or necrotic.
If the lymph node is overwhelmed, the infection can pass into the bloodstream, causing secondary septicemic plague and if the lungs are seeded, it can cause secondary pneumonic plague.
Septicemic plague. Lymphatics ultimately drain into the bloodstream, so the plague bacteria may enter the blood and travel to almost any part of the body. In septicemic plague, bacterial endotoxins cause disseminated intravascular coagulation (DIC), causing tiny clots throughout the body and possibly ischaemic necrosis (tissue death due to lack of circulation/perfusion to that tissue) from the clots. DIC results in depletion of the body’s clotting resources, so that it can no longer control bleeding. Consequently, there is bleeding into the skin and other organs, which can cause red and/or black patchy rash and hemoptysis/hematemesis (coughing up/ vomiting of blood). There are bumps on the skin that look somewhat like insect bites; these are usually red, and sometimes white in the center. Untreated, septicemic plague is usually fatal. Early treatment with antibiotics reduces the mortality rate to between 4 and 15 percent. People who die from this form of plague often die on the same day symptoms first appear.
Pneumonic plague. The pneumonic form of plague arises from infection of the lungs. It causes coughing and sneezing and thereby produces airborne droplets that contain bacterial cells and are likely to infect anyone inhaling them. The incubation period for pneumonic plague is short, usually two to four days, but sometimes just a few hours. The initial signs are indistinguishable from several other respiratory illnesses; they include headache, weakness and spitting or vomiting of blood. The course of the disease is rapid; unless diagnosed and treated soon enough, typically within a few hours, death may follow in one to six days; in untreated cases, mortality is nearly 100%.
CAUSE. The Oriental rat flea (Xenopsylla cheopsis) is a species of flea and the primary vector for the transmission of Yersinia pestis, the organism responsible for bubonic plague in most plague epidemics in Asia, Africa and South America. Both male and female fleas feed on blood and can transmit the infection.
Transmission of Y. pestis to an uninfected individual is possible by any of the following means: 1. droplet contact – coughing or sneezing on another person; 2. direct physical contact – touching an infected person, including sexual contact; 3. indirect contact – usually by touching soil contamination or a contaminated surface; 4. airborne transmission – if the microorganism can remain in the air for long periods; 5. fecal-oral transmission – usually from contaminated food or water sources; 6. vector-borne transmission – carried by insects or other animals.
Yersinia pestis circulates in animal reservoirs, particularly in rodents, in the natural foci of infection found on all continents except Australia. The natural foci of plague are situated in a broad belt in the tropical and sub-tropical latitudes and the warmer parts of the temperate latitudes around the globe, between the parallels 55 degrees North and 40 degrees South.
Contrary to popular belief, rats did not directly start the spread of the bubonic plague. It is mainly a disease in the fleas (Xenopsylla cheopis) that infested the rats, making the rats themselves the first victims of the plague. Infection in a human occurs when a person is bitten by a flea that has been infected by biting a rodent that itself has been infected by the bite of a flea carrying the disease. 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 person and the flea eventually dies from starvation. Serious outbreaks of plague are usually started by other disease outbreaks in rodents or a rise in the rodent population.
PREVENTION
Since human plague is rare in most parts of the world, routine vaccination is not needed other than for those at particularly high risk of exposure, nor for people living in areas with enzootic plague, meaning it occurs at regular, predictable rates in populations and specific areas, such as the western United States. It is not even indicated for most travellers to countries with known recent reported cases, particularly if their travel is limited to urban areas with modern hotels. The CDC thus only recommends vaccination for (1) all laboratory and field personnel who are working with Y. pestis organisms resistant to antimicrobials; (2) people engaged in aerosol experiments with Y. pestis; and (3) people engaged in field operations in areas with enzootic plague where preventing exposure is not possible (such as some disaster areas).
A systematic review by the Cochrane Collaboration found no studies of sufficient quality to make any statement on the efficacy of the vaccine.
TREATMENT
If diagnosed in time, the various forms of plague are usually highly responsive to antibiotic therapy. The antibiotics often used are streptomycin, chloramphenicol and tetracycline. Amongst the newer generation of antibiotics, gentamicin and doxycycline have proven effective in monotherapeutic treatment of plague.
The plague bacterium could develop drug resistance and again become a major health threat. One case of a drug-resistant form of the bacterium was found in Madagascar in 1995. Further outbreaks in Madagascar were reported in November 2014 and October 2017.
EPIDEMIOLOGY
Globally about 600 cases are reported a year. In 2017 the countries with the most cases include the Democratic Republic of the Congo, Madagascar and Peru. It has historically occurred in large outbreaks, with the most well-known being the Black Death in the 14th century which resulted in more than 50 million dead.
Biological weapon. Plague has a long history as a biological weapon. Historical accounts from ancient China and medieval Europe detail the use of infected animal carcasses, such as cows or horses, and human carcasses, by the Xiongnu/Huns, Mongols, Turks and other groups, to contaminate enemy water supplies. Han Dynasty General Huo Qubing is recorded to have died of such contamination while engaging in warfare against the Xiongnu. Plague victims were also reported to have been tossed by catapults into cities under siege.
In 1347, the Genoese possession of Caffa, a great trade emporium on the Crimean peninsula, came under siege by an army of Mongol warriors of the Golden Horde under the command of Janibeg. After a protracted siege during which the Mongol army was reportedly withering from the disease, they decided to use the infected corpses as a biological weapon. The corpses were catapulted over the city walls, infecting the inhabitants. This event might have led to the transfer of the plague (Black Death) via their ships into the south of Europe, possibly explaining its rapid spread.
During World War II, the Japanese Army developed weaponized plague, based on the breeding and release of large numbers of fleas. During the Japanese occupation of Manchuria, Unit 731 deliberately infected Chinese, Korean and Manchurian civilians and prisoners of war with the plague bacterium. These subjects, termed “maruta” or “logs”, were then studied by dissection, others by vivisection while still conscious. Members of the unit such as Shiro Ishii were exonerated from the Tokyo tribunal by Douglas MacArthur but 12 of them were prosecuted in the Khabarovsk War Crime Trials in 1949 during which some admitted having spread bubonic plague within a 36-km radius around the city of Changde.
Ishii innovated bombs containing live mice and fleas, with very small explosive loads, to deliver the weaponized microbes, overcoming the problem of the explosive killing the infected animal and insect by the use of a ceramic, rather than metal, casing for the warhead. While no records survive of the actual usage of the ceramic shells, prototypes exist and are believed to have been used in experiments during WWII.
After World War II, both the United States and the Soviet Union developed means of weaponizing pneumonic plague. Experiments included various delivery methods, vacuum drying, sizing the bacterium, developing strains resistant to antibiotics, combining the bacterium with other diseases (such as diphtheria), and genetic engineering. Scientists who worked in USSR bio-weapons programs have stated that the Soviet effort was formidable and that large stocks of weaponized plague bacteria were produced. Information on many of the Soviet projects is largely unavailable. Aerosolized pneumonic plague remains the most significant threat.
The plague can be easily treated with antibiotics, and some countries, such as the United States, have large supplies on hand if such an attack should occur, thus making the threat less severe.
THE BLACK DEATH
The Black Death, also known as the Great Plague or simply Plague, or less commonly as the Black Plague, was one of the most devastating pandemics in human history, resulting in the deaths of an estimated 75 to 200 million people in Eurasia and peaking in Europe from 1347 to 1351. The bacterium Yersinia pestis, which results in several forms of plague, is believed to have been the cause. The plague created a series of religious, social and economic upheavals, which had profound effects on the course of European history.
The Black Death is thought to have originated in the dry plains of Central Asia, where it then travelled along the Silk Road, reaching Crimea by 1343. From there, it was most likely carried by Oriental rat fleas living on the black rats that were regular passengers on merchant ships, spreading throughout the Mediterranean and Europe.
The Black Death is estimated to have killed 30–60% of Europe’s total population. In total, the plague may have reduced the world population from an estimated 450 million down to 350–375 million in the 14th century. It took 200 years for the world population to recover to its previous level. The plague recurred as outbreaks in Europe until the 19th century.
ORIGINS of the DISEASE
The plague disease, caused by Yersinia pestis, is enzootic (commonly present) in populations of fleas carried by ground rodents, including marmots, in various areas including Central Asia, Kurdistan, Western Asia, Northern India and Uganda.
Due to climate change in Asia, rodents began to flee the dried-out grasslands to more populated areas, spreading the disease. Nestorian graves dating to 1338–1339 near Lake Issyk Kul in Kyrgyzstan have inscriptions referring to the plague and are thought by many epidemiologists to mark the outbreak of the epidemic, from which it could easily have spread to China and India. In October 2010, medical geneticists suggested that all three of the great waves of the plague originated in China. In China, the 13th-century Mongol conquest caused a decline in farming and trading. However, economic recovery had been observed at the beginning of the 14th century. In the 1330s, a large number of natural disasters and plagues led to widespread famine, starting in 1331, with a deadly plague arriving soon after. Epidemics that may have included plague killed an estimated 25 million Chinese and other Asians during the 15 years before it reached Constantinople in 1347.
The disease may have travelled along the Silk Road with Mongol armies and traders or it could have come via ship. By the end of 1346, reports of plague had reached the seaports of Europe: “India was depopulated, Tartary, Mesopotamia, Syria, Armenia were covered with dead bodies”.
Plague was reportedly first introduced to Europe via Genoese traders at the port city of Kaffa in the Crimea in 1347. After a protracted siege, during which the Mongol army under Jani Beg was suffering from the disease, the army catapulted infected corpses over the city walls of Caffa to infect the inhabitants. The Genoese traders fled, taking the plague by ship into Sicily and the south of Europe, whence it spread north. Whether or not this hypothesis is accurate, it is clear that several existing conditions such as war, famine, and weather contributed to the severity of the Black Death.
European outbreak.
The seventh year after it began, it came to England and first began in the towns and ports joining on the seacoasts, in Dorsetshire, where, as in other counties, it made the country quite void of inhabitants so that there were almost none left alive. But at length, it came to Gloucester, even to Oxford and to London, and finally, it spread over all England and so wasted the people that scarce the tenth person of any sort was left alive. Geoffrey the Baker, Chronicon Angliae
There appear to have been several introductions to Europe. The plague reached Sicily in October 1347, carried by twelve Genoese galleys, and rapidly spread all over the island. Galleys from Kaffa reached Genoa and Venice in January 1348, but it was the outbreak in Pisa a few weeks later that was the entry point to northern Italy. Towards the end of January, one of the galleys expelled from Italy arrived in Marseille.
From Italy, the disease spread northwest across Europe, striking France, Spain, Portugal and England by June 1348, then turned and spread east through Germany and Scandinavia from 1348 to 1350. It was introduced in Norway in 1349 when a ship landed at Askøy, then spread to Bjørgvin (modern Bergen) and Iceland. Finally, it spread to northwestern Russia in 1351. The plague was somewhat less common in parts of Europe that had smaller trade relations with their neighbours, including the majority of the Basque Country, isolated parts of Belgium and the Netherlands, and isolated alpine villages throughout the continent.
Modern researchers do not think that the plague ever became endemic in Europe or its rat population. The disease repeatedly wiped out the rodent carriers so that the fleas died out until a new outbreak from Central Asia repeated the process. The outbreaks have been shown to occur roughly 15 years after a warmer and wetter period in areas where plague is endemic in other species such as gerbils.
Middle Eastern outbreak. The plague struck various regions in the Middle East during the pandemic, leading to serious depopulation and permanent change in both economic and social structures. As it spread from China with the Mongols to a trading post in Crimea, called Kaffa, controlled by the Republic of Genoa. From there the disease, infected rodents infecting new rodents, entered the region from southern Russia also. By autumn 1347, the plague reached Alexandria in Egypt, through the port’s trade with Constantinople, and ports on the Black Sea. During 1347, the disease travelled eastward to Gaza, and north along the eastern coast to cities in Lebanon, Syria and Palestine, including Ashkelon, Acre, Jerusalem, Sidon, Damascus, Homs, and Aleppo. In 1348–1349, the disease reached Antioch. The city’s residents fled to the north, However, most of them ended up dying during the journey.
Mecca became infected in 1349. During the same year, records show the city of Mawsil (Mosul) suffered a massive epidemic, and the city of Baghdad experienced a second round of the disease.
Medical knowledge had stagnated during the Middle Ages. The most authoritative account at the time came from the medical faculty in Paris in a report to the king of France that blamed the heavens, in the form of a conjunction of three planets in 1345 that caused a “great pestilence in the air”. This report became the first and most widely circulated of a series of plague tracts that sought to advise sufferers. That the plague was caused by bad air became the most widely accepted theory. Today, this is known as the miasma theory. The word plague had no special significance at this time, and only the recurrence of outbreaks during the Middle Ages gave it the name that has become the medical term.
The importance of hygiene was recognized only in the nineteenth century; until then it was common that the streets were filthy, with live animals of all sorts around and human parasites abounding. A transmissible disease will spread easily in such conditions. One development as a result of the Black Death was the establishment of the idea of quarantine in Dubrovnik in 1377 after continuing outbreaks.
The dominant explanation for the Black Death is the plague theory, which attributes the outbreak to Yersinia pestis, also responsible for an epidemic that began in southern China in 1865, eventually spreading to India. The investigation of the pathogen that caused the 19th-century plague was begun by teams of scientists who visited Hong Kong in 1894, among whom was the French-Swiss bacteriologist Alexandre Yersin, after whom the pathogen was named Yersinia pestis. The mechanism by which Y. pestis was usually transmitted was established in 1898 by Paul-Louis Simond and was found to involve the bites of fleas whose midguts had become obstructed by replicating Y. pestis several days after feeding on an infected host. This blockage results in starvation and aggressive feeding behaviour by the fleas, which repeatedly attempt to clear their blockage by regurgitation, resulting in thousands of plague bacteria being flushed into the feeding site, infecting the host. The bubonic plague mechanism was also dependent on two populations of rodents: one resistant to the disease, which acts as hosts, keeping the disease endemic, and a second that lacks resistance. When the second population dies, the fleas move on to other hosts, including people, thus creating a human epidemic.
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.
An estimate of the mortality rate for the modern bubonic plague, following the introduction of antibiotics, is 11%, although it may be higher in 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 who contract the bubonic plague, 80 percent die within eight days. Pneumonic plague has a mortality rate of 90 to 95 percent. 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.
In October 2010, the open-access scientific journal PLoS Pathogens published a paper by a multinational team that 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”.
The study also found that there were two previously unknown but related clades (genetic branches) of the Y. pestis genome associated with medieval mass graves. These clades (which are thought to be extinct) were found to be ancestral to modern isolates of the modern Y. pestis strains Y. p. orientalis and Y. p. medievalis, suggesting the plague may have entered Europe in two waves. Surveys of plague pit remains in France and England indicate the first variant entered Europe through the port of Marseille around November 1347 and spread through France over the next two years, eventually reaching England in the spring of 1349, where it spread through the country in three epidemics. Surveys of plague pit remains from the Dutch town of Bergen op Zoom showed the Y. pestis genotype responsible for the pandemic that spread through the Low Countries from 1350 differed from that found in Britain and France, implying Bergen op Zoom (and possibly other parts of the southern Netherlands) was not directly infected from England or France in 1349 and suggesting a second wave of plague, different from those in Britain and France, may have been carried to the Low Countries from Norway, the Hanseatic cities or another site.
The results of the Haensch study have since been confirmed and amended. Based on genetic evidence derived from Black Death victims in the East Smithfield burial site in England, Schuenemann et al. concluded in 2011 “that the Black Death in medieval Europe was caused by a variant of Y. pestis that may no longer exist.” A study published in Nature in October 2011 sequenced the genome of Y. pestis from plague victims and indicated that the strain that caused the Black Death is ancestral to most modern strains of the disease.
DNA taken from 25 skeletons from the 14th century found in London has shown the plague is a strain of Y. pestis that is almost identical to that which hit Madagascar in 2013.
CONSEQUENCES
There are no exact figures for the death toll; the rate varied widely by locality. In urban centres, the greater the population before the outbreak, the longer the duration of the period of abnormal mortality. It killed some 75 to 200 million people in Eurasia. According to medieval historian Philip Daileader in 2007:
The trend of recent research is pointing to a figure more like 45–50% of the European population dying during four years. There is a fair amount of geographic variation. In Mediterranean Europe, areas such as Italy, the south of France and Spain, where plague ran for about four years consecutively, it was probably closer to 75–80% of the population. In Germany and England … it was probably closer to 20%.
A death rate as high as 60% in Europe has been suggested by Norwegian historian Ole Benedictow: A detailed study of the mortality data available points to two conspicuous features about 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 percent 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 around 50 million people died in the Black Death.
The most widely accepted estimate for the Middle East, including Iraq, Iran and Syria, during this time, is for a death rate of about a third.[57] The Black Death killed about 40% of Egypt’s population. Half of Paris’s population of 100,000 people died. In Italy, the population of Florence was reduced from 110,000–120,000 inhabitants in 1338 down to 50,000 in 1351. At least 60% of the population of Hamburg and Bremen perished, and a similar percentage of Londoners may have died from the disease as well. In London, approximately 62,000 people died between the years between 1346 and 1353. While contemporary reports account of mass burial pits being created in response to the large numbers of dead, recent scientific investigations of a burial pit in Central London found well-preserved individuals to be buried in isolated, evenly spaced graves, suggesting at least some pre-planning and Christian burials at this time. Before 1350, there were about 170,000 settlements in Germany, and this was reduced by nearly 40,000 by 1450. In 1348, the plague spread so rapidly that before any physicians or government authorities had time to reflect upon its origins, about a third of the European population had already perished. In crowded cities, it was not uncommon for as much as 50% of the population to die. The disease bypassed some areas, and the most isolated areas were less vulnerable to contagion. Monks and priests were especially hard-hit since they cared for victims of the Black Death.
Persecutions. Inspired by the Black Death, The Dance of Death, or Danse Macabre, an allegory on the universality of death, was a common painting motif in the late medieval period.
Renewed religious fervour and fanaticism bloomed in the wake of the Black Death. Some Europeans targeted “various groups such as Jews, friars, foreigners, beggars, pilgrims”, lepers, and Romani, thinking that they were to blame for the crisis. Lepers, and other individuals with skin diseases such as acne or psoriasis, were singled out and exterminated throughout Europe.
Because 14th-century healers were at a loss to explain the cause, Europeans turned to astrological forces, earthquakes, and the poisoning of wells by Jews as possible reasons for the plague’s emergence. The governments of Europe had no apparent response to the crisis because no one knew its cause or how it spread. The mechanism of infection and transmission of diseases was little understood in the 14th century; many people believed the epidemic was a punishment by God for their sins. This belief led to the idea that the cure to the disease was to win God’s forgiveness.
There were many attacks against Jewish communities. In February 1349, the citizens of Strasbourg murdered 2,000 Jews. In August 1349, the Jewish communities in Mainz and Cologne were annihilated. By 1351, 60 major and 150 smaller Jewish communities had been destroyed. These massacres eventually died out in Western Europe, only to continue on in Eastern Europe. During this period many Jews relocated to Poland and Russia, receiving a warm welcome from King Casimir.
Recurrence (Second plague pandemic). The Great Plague of London, in 1665, killed up to 100,000 people.
The plague repeatedly returned to haunt Europe and the Mediterranean throughout the 14th to 17th centuries.[70] According to Biraben, the plague was present somewhere in Europe in every year between 1346 and 1671.[71] The Second Pandemic was particularly widespread in the following years: 1360–1363; 1374; 1400; 1438–1439; 1456–1457; 1464–1466; 1481–1485; 1500–1503; 1518–1531; 1544–1548; 1563–1566; 1573–1588; 1596–1599; 1602–1611; 1623–1640; 1644–1654; and 1664–1667. Subsequent outbreaks, though severe, marked the retreat from most of Europe (18th century) and northern Africa (19th century). According to Geoffrey Parker, “France alone lost almost a million people to the plague in the epidemic of 1628–31.”
In England, in the absence of census figures, historians propose a range of preincident population figures from as high as 7 million to as low as 4 million in 1300, and a post-incident population figure as low as 2 million. By the end of 1350, the Black Death subsided, but it never really died out in England. Over the next few hundred years, further outbreaks occurred in 1361–1362, 1369, 1379–1383, 1389–1393, and throughout the first half of the 15th century. An outbreak in 1471 took as much as 10–15% of the population, while the death rate of the plague of 1479–1480 could have been as high as 20%. The most general outbreaks in Tudor and Stuart England seem to have begun in 1498, 1535, 1543, 1563, 1589, 1603, 1625, and 1636 and ended with the Great Plague of London in 1665.
In 1466, perhaps 40,000 people died of the plague in Paris. During the 16th and 17th centuries, the plague was present in Paris around 30 percent of the time. The Black Death ravaged Europe for three years before it continued on into Russia, where the disease was present somewhere in the country 25 times between 1350 and 1490. Plague epidemics ravaged London in 1563, 1593, 1603, 1625, 1636, and 1665, reducing its population by 10 to 30% during those years. Over 10% of Amsterdam’s population died in 1623–1625, and again in 1635–1636, 1655, and 1664. The plague occurred in Venice 22 times between 1361 and 1528.[85] The plague of 1576–1577 killed 50,000 in Venice, almost a third of the population.[86] Late outbreaks in central Europe included the Italian Plague of 1629–1631, which is associated with troop movements during the Thirty Years’ War, and the Great Plague of Vienna in 1679. Over 60% of Norway’s population died in 1348–1350. The last plague outbreak ravaged Oslo in 1654.
In the first half of the 17th century, a plague claimed some 1.7 million victims in Italy or about 14% of the population. In 1656, the plague killed about half of Naples’ 300,000 inhabitants. More than 1.25 million deaths resulted from the extreme incidence of plague in 17th-century Spain. The plague of 1649 probably reduced the population of Seville by half. In 1709–1713, a plague epidemic that followed the Great Northern War (1700–1721, Sweden v. Russia and allies) killed about 100,000 in Sweden, and 300,000 in Prussia. The plague killed two-thirds of the inhabitants of Helsinki and claimed a third of Stockholm’s population. Europe’s last major epidemic occurred in 1720 in Marseille.
The Black Death ravaged much of the Islamic world. The plague was present in at least one location in the Islamic world virtually every year between 1500 and 1850. Plague repeatedly struck the cities of North Africa. Algiers lost 30,000–50,000 inhabitants to it in 1620–1621, and again in 1654–1657, 1665, 1691, and 1740–1742. Plague remained a major event in Ottoman society until the second quarter of the 19th century. Between 1701 and 1750, thirty-seven larger and smaller epidemics were recorded in Constantinople and an additional thirty-one between 1751 and 1800.[100] Baghdad has suffered severely from visitations of the plague, and sometimes two-thirds of its population has been wiped out.
The third plague pandemic (1855–1859) started in China in the mid-19th century, spreading to all inhabited continents and killing 10 million people in India alone. Twelve plague outbreaks in Australia between 1900 and 1925 resulted in well over 1,000 deaths, chiefly in Sydney. This led to the establishment of a Public Health Department there which undertook some leading-edge research on plague transmission from rat fleas to humans via the bacillus Yersinia pestis.
The first North American plague epidemic was the San Francisco plague of 1900–1904, followed by another outbreak in 1907–1908.
Names. The phrase “black death” (mors nigra) was used in 1350 by Simon de Covino or Couvin, a Belgian astronomer, who wrote the poem “On the Judgment of the Sun at a Feast of Saturn” (De judicio Solis in convivio Saturni), which attributes the plague to a conjunction of Jupiter and Saturn. In 1908, Gasquet claimed that the use of the name atra mors for the 14th-century epidemic first appeared in a 1631 book on Danish history by J. I. Pontanus: “Commonly and from its effects, they called it the black death” (Vulgo & ab effectu atram mortem vocatibant). The name spread through Scandinavia and then Germany, gradually becoming attached to the mid-14th-century epidemic as a proper name. However, atra mors is used to refer to a pestilential fever (febris pestilentialis) already in the 12th-century On the Signs and Symptoms of Diseases (Latin: De signis et sinthomatibus egritudinum) by French physician Gilles de Corbeil. In England, the phrase “Black Death” is first used to refer to the 14th-century epidemic in 1823. Writers contemporary with the plague described the event as a “great plague” or “great pestilence”.