Ring around the rosies,
A pocket full of posies,
All fall down.
~~Children's plague rhyme
Most of us played "Ring Around the Rosie" as kids. But did you know that it comes to us from a little rhyme about the plague? "The rosies" are those who have the high fever that comes with plague; "a pocket full of posies" comes from the belief that carrying a small nosegay to sniff would ward off harmful vapors that carried the disease; "atchoo atchoo" comes from the coughing and sneezing that comes with the pulmonary form of the disease; and "all fall down" simply indicates that when the plague was raging, most people died.
Plague is caused by Yersinia pestis, a small Gram negative bacteria with a characteristic "safety pin" appearance due to the way it takes up stain. Because this is considered a dangerous organism and an agent of bioterrorism, at the lab where I worked, we never received the plague bacillus as an unknown, but we did sometimes get another species of the genus Yersinia, and it does have a very characteristic appearance upon staining. Outbreaks in humans still occur in rural communities or in cities. In the United States, the last urban plague epidemic occurred in Los Angeles in 1924-25. Since then, human plague in the U.S. has occurred as sporadic cases in rural areas, with an average of 10 to 20 cases each year. (About 14% are fatal.) Globally, the World Health Organization reports 1,000 to 3,000 cases of plague every year. Streptomycin is the antibiotic of choice. Gentamicin is used when streptomycin is not available. Tetracyclines and chloramphenicol are also effective.
There are three forms of plague:
Bubonic plague spreads via fleas from rats to humans and results in infected glands in the groin, armpit, or neck. These swollen glands are called buboes. The bacteria multiply in the bloodstream, which is ultimately the cause of death. Without antibiotics, there is up to a 90% mortality rate.
Septicemic plague occurs when the bacteria multiply in the bloodstream before buboes develop, and without treatment, results in rapid death.
Pneumonic plague is a virulent form of pneumonia and can spread directly from man to man when the infected person coughs or sneezes.
The pneumonic form is of most concern, because it skips the usual transmission route from rat to flea to human. The rapid transmission from man to man is what causes pandemics.
There have been three great pandemics (along with multiple lesser ones) in history: the plague of Justinian in 540-90; the Black Death of 1346-61; and the plague of 1665-6 called the Great Plague of London.
Effects on history
Plague of Justinian
There are few records of this pandemic, but description of symptoms indicate the bubonic form. Emperor Justinian expanded the Roman Empire, and his code of laws were the basis of justice for years to come. He assembled an excellent army and built many buildings and fortresses, but despite the potential for a renewed and stronger Roman Empire, when he died in 565, the Empire was poorer and weaker due to pandemic plague. Mortality rose to around 10,000 per day, and 40% of the population of Constantinople died. Christianity became established as a world religion because the Roman Empire suffered from devastating disease after the life of Christ. The concept of healing medicine arose in place of Roman remedies and sacrifices to various gods.
The Black Death
This was originally called the Great Dying by the population at the time, and was a combination of bubonic and the more easily transmitted pneumonic forms. It is widely believed to be one of the reasons for the end of feudalism; so many peasants died that there was a severe labor shortage, so wages were doubled and peasants were able to rent land. Fewer peasants meant that less land was tilled, so cattle and sheep multiplied rapidly and resulted in new sources of income such as wool and leather. Europe's inhabitants had cut down so many trees for firewood over the centuries that the continent's ecology was threatened. Massive die-offs of the human population allowed the forests to repopulate, and most of the great forests of Europe date from the late Middle Ages.
Religious orders and clerics were severely decimated. In Montpellier, France, only 7 of 140 Dominican friars survived; in Marseilles, 150 Franciscans died--the entire monastery; in Germany, one third of the clergy succumbed. This loosened the hold of the Latin language on education and ended its dominance as the language of Europe. The Church was forced to repopulate its ranks with those who spoke the common languages. The hold of the Church upon the populace was lessened, as people felt that God had abandoned them, and saw corrupt and frightened clergy refuse to administer last rites or hear confession. In schools, English and French--the common languages--began to be used, rather than Latin, bringing the possibility of knowledge and some education to the commoner.
In times of great stress and uncertainty, there is a tendency to find a scapegoat. Europeans found their scapegoat in the Jewish population, accusing them of poisoning wells and "corrupting the air." Mass burnings were conducted, and by 1351, hardly any Jews were left in Central Europe.
While physicians were unable to cure the disease, it brought about the beginnings of public health. Quarantines were effected, accurate records began to be kept to track the progress of the disease, and infected ships were isolated at an island for 40 days.
Deaths between 1348 and 1351 are estimated at 23,840,000 people, 31% of Europe's population.
The Great Plague of London
This pandemic was also a combination of the bubonic and pneumonic varieties. The development of public health continued, with garbage collection and meat market inspections. This made a mark on the disease but it was still present. European homes at this time consisted of unseasoned wood and thatched roofs. The straw of the roofs made a perfect home for plague-carrying rats, and allowed their fleas to drop down on the house's inhabitants. A plague pandemic was last seen in London in 1665, because the Great Fire of London in 1666 burned 13,200 wood homes; new homes were built with brick and tile roofs, eliminating much of the rats' close cohabitation with humans. A different species of rat, the larger grey rat, one that rarely carried plague, began displacing the plague-carrying black rat, again cutting down on the possibility of rat-flea-human transmission.
After the plague pandemics died down in the 1700's, a different attitude about population emerged, with the result of natural population control. Massive die-offs due to plague came about because of poverty, over-population, and famine. Peasants began delaying marriage and childbirth, waiting until both sets of in-laws had died, which made room at the dinner table and meant fewer mouths to feed. 90% of girls of child-bearing age around the world bore children by the age of 14, while only two-thirds of European women bore children by that age.
Humans came out of the Middle Ages feeling like survivors of a biological holocaust. While Nature had previously been respected and sometimes revered, it was now seen as a powerful enemy that needed to be subdued. This set the stage for the centuries to come in which technological development was seen as a way to control the capricious whims of the deadly and unknown forces of Nature.
As you can see, this is a topic of great interest to me, and I have and have read several books about it. I firmly believe that it is a cautionary tale, and that the potential exists for a modern-day pandemic, whether a new strain of bacteria or a mutated virus. While public health has improved greatly, a previously unknown organism would wreak havoc upon the population of the world. (And this IS a global concern now, considering the travel possibilities.) Contrary to what some might believe, in the face of an unknown organism, our immune systems might not be able to mount defenses fast enough, and that could be devastating. In that case, firm and well-thought out plans need to be in place for quarantine and control. Do I believe this will happen? I have no idea. But I believe it could happen, and I find that pretty damn unsettling.
I hope you've enjoyed this installment of Infectious Disease and World History! While nothing has had quite the historical impact of the plague, in the future I'll write about things like malaria, yellow fever, smallpox, and that all-time favorite, syphilis! (That one is particularly interesting!)
Cartwright, Frederick. (Biddis, Michael, collaborator). Disease and History. New York: Dorset Press, 1972
Karlen, Arno. Man and Microbes. New York: Simon and Schuster, 1995
Nikiforuk, Andrew. The Fourth Horseman. London: Phoenix, 1991
Ziegler, Philip. The Black Death. Dover: Allen Sutton Publishing, 1991