Abraham J. Weissman
Chapter 11 of Guns Germs and Steel by Jared Diamond was based around how epidemic diseases or crowd diseases were brought to mesa America by the Western world. Throughout the chapter, Diamond talks a great deal about how diseases spread through cultures and societies, but what stood out to me was the example of the outbreak of Measles on the Faeroes Islands. The disease killed over half of the population, left, and then was brought back by a carpenter on a ship from Denmark beginning the process again. What interests me is how this could happen? How does a disease like the measles continue to survive when on an island like this, those that are infected either die, live through it developing immunities or are born with immunities in their genes and are never infected. There are some diseases such as O’nyong-nyong in Africa or Fort Brag Fever in America that truly die out, so how or why do some diseases lie dormant and re-occur like that?
The thought that diamond brings up is that western societies live in close proximity to a large amount of varied domestic animals while mesa American people were not heavily reliant or in contact with domesticated animals. The thought here being that domesticated animals are then carriers of diseases, so more diseases existed in the western world then they did in mesa America and were also more dangerous. But then how could, on such an isolated island where all of the animals and the people had died who did not have or develop an immunity to the disease, the measles come back and then again wipe out over half of the population? Wouldn’t the immunities remain then making the society immune to that disease?
Crowd diseases such as measles, influenza, the bubonic plague and small pox that kill vast amounts of people, then died off, but could still come back require a huge population for them to take hold, and then could come back if the population regenerates itself with a number of over half a million because then due to natural selection, the immunities fade out. This would account for populations becoming susceptible to the disease again. But why do some diseases die off and are never re-occurring when some can come back?
An article I read about a re-occurrence of the Pneumonic plague in China written in The Faster Times(1) accounts for this anomaly in that some diseases lie dormant in animals, being carried by fleas. So the fleas infect the animals and then the animals infect the people, or the fleas also directly infect the people. But then again, how can some diseases lie dormant in animals and continue to come back while others simply die out?
Today, Modern Medicine can be attributed to this for several different reasons. First, large societies like the US require that people in a close proximity, like schools get vaccines for specific crowd diseases like the measles and the mumps. Other times we have developed anti-biotics that treat diseases like the bubonic plague. This then may eventually weed out all epidemic diseases.
Though these answers do not completely answer my questions, they do begin to help me understand the mysteries of the spread of diseases.
(1) Akpogheneta, Onome. "Quarantine: Pneumonic Plague Outbreak in China." Faster Times (2009): n. pag. Web. 17 Apr 2011. <http://thefastertimes.com/globalpandemics/2009/08/09/quarantine-pneumonic-plague-outbreak-in-china/>.