Monday, June 9, 2014

Further on McNeill and Civilized Societies’ disease advantage

I probably should have quoted some more.  He doesn’t mean Civilization in the Enlightenment sense, but in the sense of being congregated in cities. [His definition of “Civilization” will be expanded a bit in a subsequent note.]  Diseases that weren’t possible in Hunter-gatherer days evolved when men clustered close together in cities.  Diseases like mumps, chicken pox and measles are endemic amongst civilized Europeans, but have been fatal to people who have never before been exposed to them. 

McNeill quotes the effects a disease introduced into Australian rabbits in 1950 in hopes of eliminating them.  Something like 98% of them were killed immediately, but when the 2% had offspring, only 70% died.  28% had immunity. The percent dying decreased with each generation until 75% survived and that survival rate remained.  I probably haven’t recalled these numbers precisely but they were something like that.  McNeill suggests that the introduction of a virulent disease in a people with no immunity will have a similar result – perhaps not a death rate of 98% but a significant one.  A rabbit generation is less than a year; so in a very few years they were almost back to where they started, but a people like the Aztecs would have taken much longer. 

Speaking of the Aztecs complicates this issue because the Aztecs were civilized in the McNeill sense.  It was just that the diseases they were confronted with in the 1500s had developed in Europe after the Amerindians had come over the Bering Straits land bridge around 15,000 years ago.  It was after that the Europeans developed agriculture and began clustering in towns and later cities; becoming in McNeill’s definition, along with their endemic diseases, civilized.

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