Plague (Yersinia pestis)

Plague, or Black Death as it is commonly called, is an infectious disease caused by the bacterial agent Yersinia pestis. Popular tradition dictated that the disease derived its ominous name from the black coloration of the swollen and very tender lymph glands that characterize the bubonic form of the infection, or the black coloration of those who died of septic plague. Other experts suggested that the name came from the Latin atra mors, which translates into 'dreadful death' or 'black death.' This name seemed only to have been used since the 18th Century. The disease is transmitted from rodents to humans by Xenopsylla cheopis, the oriental rat flea, or Pulex irritans, the human flea. The Yersinia pestis bacterium is credited with not only immeasurable human destruction, but also credited with facilitating sociological sea changes that altered the course of human civilization. A prominent example of such change was the demographics transformation in the late 14th Century Europe that destroyed the feudal system.

Medieval History of Plague

So Nature killed many through corruptions,

Death came driving after her and dashed all to dust,

Kings and knights, emperors and popes;

He left no man standing, whether learned or ignorant...

~William Langland (c. 1330-1387)

The first global pandemic of plague was believed to have began in the Middle East in the in the 6th Century CE. It reached Egypt by 542 CE, brought destruction upon the Eastern Roman Empire under Justinian, and spread across the European Continent. Constantinople suffered approximately 40% fatality, and the destruction ushered in the Dark Ages in Europe. Spontaneous outbreaks continued until the 8th Century CE.

The second pandemic began in China in 1330s. Between the years 1337 and 1346, a series of environmental disasters ranging from floods to locusts to earthquakes struck China. On the heels of these disasters came a plague that slowly spread westward along trade routes. Gabriel de Mussis of Piacenza chronicled how the plague arrived in Europe. In 1346, the plague arrived in Asia Minor and the suffering precipitated violence between the Tartars and the Genoese merchants who retreated to the Crimean coastal city of Kaffa, the present day Ukrainian city of Feodosia. The Tartars besieged the city and catapulted bodies of plague victims across the walls. Plague spread within the besieged city, more likely because of flea-infested rats rather than the gruesome Tartar projectiles. The Genoese merchants abandoned the city to return to Europe with the deadly bacteria in tow. Historians suspected the plague entered Europe through other trade routes as well. By 1348, the plague swept into Sicily and the Italian peninsula.

Of the symptoms, Giovanni Boccaccio in The Decameron (Translated in 1930 by Richard Aldington) wrote:

"The symptoms were not the same as in the East, where a gush of blood from the nose was the plain sign of inevitable death; but it began both in men and women with certain swellings in the groin or under the armpit. They grew to the size of a small apple or an egg, more or less, and were vulgarly called tumors. In a short space of time these tumors spread from the two parts named all over the body. Soon after this the symptoms changed and black or purple spots appeared on the arms or thighs or any other part of the body, sometimes a few large ones, sometimes many little ones. These spots were a certain sign of death, just as the original tumor had been and still remained."

Chronicles disagreed about the length of the disease; some describing bubonic plague recorded that death arrived in 4-5 days while those who described pneumonic plague placed death at 3 days. Other accounts described death within a few hours, a characteristic of septic plague. Chronicles also disagreed about how the disease was transmitted between victims: through person-to-person contact or through the poisoned air called miasma. All agreed to the horrifying nature of the symptoms as the victims wasted away in excreted, putrid bodily fluids. All agreed to the disease's destruction of the social fiber of society as victims were abandoned by fearful family and friend, and the legitimacy of civil and religious authority eroded. Many historians maintained that the labor shortage of the late 14th Century created by the plague fueled demands for higher wages and facilitated the end of feudalism and rise of the middle class.

In the 14th Century, the lack of adequate medical knowledge to address questions regarding the plague's origins and transmission inspired social panic and massive witch hunts. Chronicles recorded that women who survived the epidemic were frequently attacked as witches and 'plague-spreaders.' One legend popular in central Europe and Scandinavia blamed the plague on Pest Jungfrau, a maiden who traversed the skies as a blue flame waving her hand or a red handkerchief to spread the deadly disease.

Home remedies against infection ranged from practical suggestions regarding sanitation and disposal of corpses to bathing the victims in rose water and vinegar to drinking stewed mixtures of ground eggshells and marigold flowers. Some scholars speculated that 'Ring-a-Ring-a-Roses' alluded to the plague. In accordance with the popular British nursery rhyme, a pocket full of posies or fragrant herbs and spices were used to ward off the miasma that carried plague infection. Conjectures also connected the popular song "Scarborough Fair" to the plague. The parsley, sage, rosemary and thyme mentioned in the song could have alluded to herbs that were used to ward off plague. Flagellants, who believed the deadly epidemic was punishment from God for human sins, publicly whipped their own flesh as penitence. Pope Clement VI denounced the flagellants as heretical, but their popularity persisted in times of plague outbreaks. When King Philip VI of France commissioned professors at the University of Paris to study the plague in 1348, they attributed the epidemic to the fact that Saturn was in the house of Jupiter.

Historical records on the mortality rate vary widely. Most agreed mortality numbered at least 20 million people in Europe and was higher in cities than the countryside. Best estimates by historians suggest that between 20% and 30% of the population of Europe was destroyed by the plague. The next global epidemic that would cause more deaths was the Spanish influenza of 1918 that killed 50 million in a year.

The plague remained in Europe until the Great Plague of London in 1665. Charles II and his court left London for Oxford. The plague started in the overcrowded poor parish of St. Giles-in-the-Field. Authorities quarantined all infected households; a red cross and the words 'Lord have Mercy on Us' were painted on the door to indicate a doomed house. At night, the dead were collected and buried in large communal pits, one at Aldgate and one at Finsbury Fields. In an effort to control the epidemic, the Mayor of London ordered all cats and dogs to be destroyed, but such measures only worsened the plague by allowing rats to thrive without their natural predators. The plague in London caused 15% fatality in the population. Then the plague reached an abrupt conclusion. The Great Fire of London in 1666 that destroyed the city was believed to have destroyed the plague as well.

In the late 20th Century, medical historians have questioned the exact nature of Black Death. One argument, spearheaded by British zoologist Graham Twiggs and Edward Thompson of the University of Toronto, suggested that in addition to bubonic plague, anthrax outbreaks augmented the high fatality rates that devastated the Medieval European civilization. Physicians in the 14th Century may have conflated the similar preliminary symptoms of both diseases. Further, plague ravaged 14th Century Iceland, but rats were not introduced to Iceland until the 17th Century. Many historians concede that the two diseases perhaps coexisted to bring about the high fatalities associated with the Black Death.

19th and 20th Century History of Plague

In 1894, Swiss-French bacteriologist Alexandre Yersin of the Pasteur Institute was credited as the first to isolate the bacteria Yersinia pestis that causes the plague. In 1894, Yersin joined the Colonial Health Corps and traveled to Hong Kong where the plague raged. In Hong Kong, Yersin isolated the bacteria, connected the bacteria with bubonic plague, and published his results in French. At roughly the same time, Japanese bacteriologist Shibasaburo Kitasato also isolated the bacteria in Hong Kong and published his results in Japanese and English. Yersin named the bacteria Pasteurella pestis after his mentor, Louis Pasteur, but by 1970, the bacteria was renamed Yersinia pestis after the bacteriologist who discovered the bacteria and linked it to the disease.

In 1896, during an outbreak of plague in Bombay, the Bombay authorities turned to Waldemar Haffkine for a medical miracle. Haffkine was a Jewish bacteriologist born in Odessa. Denied positions because of his Jewish origin, he moved to Geneva, Switzerland and later discovered a vaccine for cholera at the Pasteur Institute. For months, Haffkine raced to find a vaccine for Yersinia pestis in his makeshift laboratory at Grant Medical College. By January 1897, a vaccine created with killed plague bacteria was developed. Haffkine tested the vaccine on himself before testing it on volunteers from the Byculla jail. In 1898, EH Hawkin and Paul Louis Simond were credited with discovering the role of rats in transmission of bubonic plague, and in 1900, Simond was further credited with uncovered the role of the flea as well.

The third pandemic of plague began in 1892 in the Yunnan Province of China, and spread around the world killing an estimated 6 million in India alone. In 1899, a ship from Hong Kong arrived in San Francisco with two plague victims onboard. Although initially quarantined on Angel Island, the ship was allowed to dock and in 1900, and a fatal case of bubonic plague was discovered in San Francisco's Chinatown. Businessmen feared that any public announcements would hurt San Francisco economically so the city executed a door-to-door search operation in Chinatown. Local authorities burned all houses that contained plague victims and moved the Chinatown population to camps outside the city. Many hid sick and dead relatives. The governor of California denied all allegations of plague until the Surgeon General, with the intercession of President McKinley, had to force new anti-plague legislation on the city. A 1906 earthquake and a 1907 bounty placed on rats finally helped end the epidemic. At the beginning of the 21st Century, the third pandemic of plague continues to appear sporadically on a worldwide scale except in Australia and Antarctica.

In the late 20th Century, bubonic plague continued to appear in central, southwestern, and northern India. In September 1993, an earthquake measuring 6.4 on the Richter scale caused more than 10,000 deaths in the Western Indian state of Maharashtra. In 1994, the monsoons flooded low-lying slum areas in the city of Surat and left in its wake piles of garbage lingering in the narrow streets. According to epidemiologists, the first natural disaster dislocated rodent wildlife from nearby forested areas and brought them in contract with domestic rats. The second natural disaster and the garbage piles left in its aftermath provided the plague-carrying rats with a ready home. The two natural disasters were also aided by Hindu cultural and religious proclivity against touching the bodies of dead animals (therefore ignoring plague-ridden corpses rather than disposing of them) and against killing rats.

In August 1994, in the village of Mamala near Beed, a city in the state of Maharashtra, rats began to die off. The first human cases were reported in the Bir district of Maharashtra. By September, migrant workers carried the pneumonic form of the plague to Surat, a historic business area about 200 km north of Bombay in the state of Gujarat. Between 26 August and 18 October, 693 cases of bubonic or pneumonic plague were discovered, and 56 victims died nationwide. Panic spread. The outbreak severely damaged investor confidence in Indian products and a quarantine was placed on travel and exports from India. The economic cost in Surat alone was estimated at 600 million dollars.

Plague as a Biological Weapons Agent

After the Tartar's transformation of plague victims into bioweapons with catapults in 1346, it was the Japanese during World War II that then developed plague into a biological weapons agent. In Unit 731, the Japanese biological weapons program in Manchuria headed by army officer and physician Shiro Ishii, the flea bomb or Uji-50 was created. The simple design of the bomb was a ceramic container filled with plague-infested fleas and flour. Once the container reached the ground and broke, the flours would attract rats, the fleas would mount the rats, and the rats would spread the disease. The Japanese tested the weapon on Manchurian villages. One witness wrote:

"I was fifteen years old at the time, and I remember everything clearly. The Japanese plane spread something that looked like smoke. A few days later we found dead rats all over the village. At the same time, people came down with high fevers and aches in the lymph nodes. Every day, people died. Crying could be heard all through the village. My mother and father - in all, eight people in my family - died. I was the only one in my family left."

Rats infested with plague-carrying fleas were also released by the Japanese. Nobuo Kamaden, a former Unit 731 member, spoke of releasing 500-gram rats with 3,000 plague-carrying fleas into local populations. Chinese prisoners called 'logs' were infected with the plague. Autopsies were performed on these prisoners without the benefit of anesthesia and before they had fully died to harvest fresh tissue samples and infected organs. It was reported that Ishii had devised, a plan to send kamikaze bombers loaded with plague to San Diego, California. The operation was scheduled for 22 September 1945. The Atomic bomb was dropped on Hiroshima on 6 August 1945.

Beyond bubonic plague spread by plague-carrying fleas, the Yersina pestis bacteria would most likely be weaponized as aerosolized, antibiotic resistant pneumonic plague, the most deadly form of the disease. During the 1950s and 1960s, the United States and the Soviet Union biological weapons programs both experimented with aerosolized Yersina pestis. The US program code named Yersina pestis LE. In a 1970 report, the World Health Organization (WHO) estimated that 50 kilograms of Yersina pestis bacteria sprayed over a city of 5 million inhabitants would result in 150,000 cases of pneumonic plague and 36,000 deaths. In 1995, a white supremacist employed in an Ohio lab acquired samples of Yersina pestis, but was arrested before he proceeded further.

Aerosolized pneumonic plague remains one of the most deadly biological weapons agents due to universal susceptibility to the disease, high morbidity and mortality induced by the disease, and quick person-to-person transmission of the pneumonic form of disease.