Thursday, September 1, 2016

Germs and Plagues

History Book Club
Wednesday, August 31, 2016
Germs and Plagues

William H. McNeill, Plagues and Peoples, New York: Anchor Books, 1976, 1998

            How did the Spanish Conquistadores, with a few hundred men, conquer the Aztecs and Incas—developed civilizations numbering in the millions? How did Cortez overcome Montezuma and the Aztecs in Mexico? How did Pizarro conquer the Incas of Peru?
            How did the religions of the Indians of South America disappear so rapidly, and why did millions accept Christianity?

            The lopsided impact of infectious diseases upon the Indians of South America offered a key to the military and cultural conquest, and that is the key that McNeill uses to examine the whole course of human history. This is the story of what happens when people who have grown immune to a disease contact a population that has never been exposed to that disease.  The consequences can be disastrous.

            This book aims to bring the history of exposure to infectious disease into the realm of historical explanation by showing how patterns of disease have affected human affairs.

             McNeill begins with a few key concepts, and the first is disease and parasites.  We are parasites, and host for parasites.

            We host microparasites—viruses, bacteria and multi-celled creatures. Some make us sick and can kill us; some are combatted and consumed by our white blood cells; and others just hang around in our bodies, not causing much or any trouble, but perhaps waiting for the opportunity to jump to another organism where their effect can be much more dangerous.

            We are also subject to macroparasites.  Once we might have had to worry about being eaten by wolves or lions, and later, the conqueror would allow us to live and produce food, and we’d be allowed to keep enough to sustain ourselves, but he would get the rest. You can see we still have macroparasites.

            In England in the 18th century many cattle and sheep had been fenced into separate fields, so that there was much less exchange of diseases with other herds.  Not only did this produce healthier livestock, but it greatly reduced diseases transmitted from livestock to humans.  At this time farmers were learning of more productive farming techniques, including growing alfalfa for livestock.  This resulted in greatly improved food production, and humans were eating more protein, which led to production of more protein antibodies to fight disease more effectively.

            Because French farmers had not yet learned to fence off herds, these results did not appear there until the 19th century.

            McNeill shows us how, as men were able to move more swiftly across the globe, how easy it was to spread germs.  Marching armies were especially effective at spreading disease.  So were the millions making the annual hajj pilgrimage from all over the Moslem world to Mecca, and back again.

            Disease often killed many thousands of an invading army.  When Alexander the Great’s army reached India it was disease, not opposing troops, who stopped his world conquest.

Bubonic Plague symptoms

            Bubonic plague has been a killer over many centuries, but it was not until 1894 when doctors discovered the connection between burrowing rodents, fleas and humans, transmitting Pasturella pestis, that eradication could become effective. The disease spread time and again by Mongol horsemen raiding in China and Europe, carrying a few infected rats in their saddlebags.

            Chinese records show several times in the middle ages when 90% of a province would be wiped out by the plague. At some periods in history there were centuries without outbreaks of the disease, as it traveled within colonies of burrowing rodents—squirrels, rats, marmots and the like.

            Napoleon sent troops to suppress an uprising in Santo Domingo in 1802, but yellow fever and other tropical diseases destroyed a force of 33,000 men, and led him to give up his visions of empire in America and sell the Louisiana Purchase to America.

            Until the 19th century, McNeill writes, cities were too polluted to sustain themselves.   As city-dwellers died, they were replaced by healthy people from the countryside. Only in the 1800s did the balance shift, so that city-dwellers, who had become immune to diseases, made the populations of cities self-sustaining.

            Cholera is an interesting story.  This disease is spread by people drinking the same water that others have used for their sewage, and as cities began to build sewers that transported wastewater to areas where it would not affect the drinking water supply, cholera began to become less of a threat. 
            Note that many huge cities in Africa and South America today lack sanitary facilities for millions who live in shantytowns around the central city, and cholera is only one of the diseases always threatening them.

            McNeill’s description of efforts to control smallpox leaves one’s head spinning, because it starts in the middle and works forward and then backward.

            To simplify, a wandering wise man from India taught the Chinese a method for inoculation against smallpox in the 11th century.  Inoculation began in England in 1721, and the royal family were inoculated the next year.  This involved inserting a small bit of the disease under the skin, and usually created a slight dose of the disease, but then immunized the patient.

            In 1798 an alert English country doctor, Edward Jenner, noticed that milkmaids, who worked around cattle and were exposed to cowpox, attained immunity to smallpox.  Cowpox, much less harmful to humans, was provided as an inoculation, and this began the virtual elimination of the disease.

            This book, initially published in 1976, includes a new, 1998 forward which discusses the then newest epidemic, that of AIDS.

            McNeill’s view of the human situation isn’t all that encouraging. We face microparasites within and macroparasites above, around and beyond.  As soon as we become immune to smallpox or clean up our lives to protect against cholera, along comes AIDS, Ebola, or Zika; or a new macroparasite like a new tax, or a higher rent, or some other problem. 


Wednesday, August, 31, 2016: Germs and Plagues: A history of epidemics in the world. Plague of Athens (429 BC), Plague of Justinian (541 AD), “Black Death” in 1346, Cocoliztli Epidemic in Mexico (1528), Wampanoag Smallpox in 1616, 1918 Flu Pandemic, more.

Wednesday, September 28, 2016: Scaremongering and Witch Hunts in America. Salem Witch Trials, House Un-American Activities Committee; McCarthy Investigations; more.

Wednesday, October 26, 2016:  Political Parties in America. Whigs, Know-Nothings, Federalists, Copperheads; Communists, Socialists, Republicans, Democrats, more.

Wednesday, November 30, 2016: Colonization in America. Jamestown, Plymouth, Gloucester, St. Augustine, Junipero Serra, Roger Williams, Quebec, Nieuw Amsterdam, more.

December:  No Meeting

Wednesday, January 18 (vice 25), 2017: History of Cape Ann
Wednesday, February 22, 2017:
Wednesday, March 29, 2017:
Wednesday, April 26, 2017:
Wednesday, May 31, 2017:


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