2. Impact of Diseases

2. Impact of Diseases - MBI 111 - Microorganisms and Human...

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    MBI 111 - Microorganisms and Human Disease 2. Impact of Infectious Diseases on Development of Human Societies
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    Antiquity to Middle Ages Development of Endemic Levels Development of endemic levels of infectious diseases communicable diseases developed between time cities first arose (~10,000 years ago) and 500 BC population requirements 250,000 for establishment and maintenance of infectious diseases epidemic pattern overhead epidemic pattern example overhead factors increasing disease transmission crowding in these cities infections transmitted by contact and insects farming practices (flooding) infections transmitted by water ingestion large-scale ritual gatherings spread between cities
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    Antiquity to Middle Ages Development of Endemic Levels diseases became endemic in the cities over time: populations adapted to infectious agents infectious agents adapted to populations territorial expansion enhanced by endemic disease: populations became resistant to endemic diseases their neighbors remained susceptible made territorial expansion much easier (biological threats) territorial expansion also limited by disease reservoirs human reservoir (infected invaders) animal reservoir (African Savannah and sleeping sickness)
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    Antiquity to Middle Age Early Thoughts about Diseases Early thoughts: cause and transmission of infectious diseases ancient Egyptians and Indians - pestilences were punishments unleashed on humans by divine judgment as retribution for wicked behavior Hippocratic school (400 BC to 500 AD) diseases resulted from imbalance of the four humors : blood (sanguine) yellow bile (choleric) optimistic, cheerful angry, hot tempered black bile (melancholic) mucous (phlegmatic) depressed not easily excited
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    Antiquity to Middle Age Selected Diseases and Their Impact on Human Societies Plague caused by Yersinia pestis gram (-) rod bubonic plague transmission: reservoir - rodents vector - Xenopsylla cheopis (rat flea) normally fleas infest rats when rats die, fleas find other blood meals (humans)
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    Antiquity to Middle Age Selected Diseases and Their Impact on Human Societies Plague caused by Yersinia pestis gram (-) rod 3 forms of disease bubonic septicemic pneumonic bubonic plague transmission: reservoir - rodents vector - Xenopsylla cheopis (rat flea) normally fleas infest rats when rats die, fleas find other blood meals (humans)
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    Antiquity to Middle Age Plague bubonic plague pathogenesis: fever, chills and prostration rapidly reaches lymph nodes (axilla, neck, groin) hemorrhaging in nodes causes swellings (buboes) purple-black splotches from hemorrhage seen through skin mortality 50-90% if untreated 15% when diagnosed and treated
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    Antiquity to Middle Age Plague septicemic plague transmission: develops from bubonic plague (80%) acquired from fleas (20%)
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This note was uploaded on 04/07/2008 for the course MBI 111 taught by Professor Clark during the Spring '07 term at Miami University.

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2. Impact of Diseases - MBI 111 - Microorganisms and Human...

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