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Chapter 4: An Arms Race Without Ends

Red Queen Principle. ??it takes all the running you can do, just to keep in the same place."-The Red Queen(from Alice in Wonderland)Example: Fox and rabbits. Trial and Error. Evolution is trial and error ? there is no rational planning or fresh starts.. Host vs. Pathogen Advantage. Hos

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Chapter 4: An Arms Race Without Ends

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    2. Chapter 4: An Arms Race Without Ends

    3. Red Queen Principle it takes all the running you can do, just to keep in the same place. -The Red Queen (from Alice in Wonderland) Example: Fox and rabbits

    4. Trial and Error Evolution is trial and error there is no rational planning or fresh starts.

    5. Host vs. Pathogen Advantage Host Advantage People who have had a disease are less likely to be re-infected because their body is prepared for that particular pathogen Pathogens Advantage Small size Large numbers Evolves quickly

    6. Resistance to Penicillin 1941 all are vulnerable 1944 some have evolved 1950s methicillin is introduced Bacteria evolves to be unaffected Today 95% show some resistance

    7. Bacterial Resistance to Antibiotics Tuberculosis Once controlled by antibiotics, now kills 50% of its hosts

    8. Prolonged Exposure Prolonged exposure to antibiotics can build up resistances Example: Antibiotics in eggs and milk

    9. Virulence Virulence The ability of the pathogen to use the hosts resources for itself PERSONAL CONTACT LESS VIRULENT INSECT MORE VIRULENT

    10. Cultural Vectors Ways of transmitting disease in everyday life Unsanitary water In hospitals Unwashed hands Thermometers Eating utensils

    11. Immune System Response The immune system makes two kinds of mistakes: Attacks when it should not Fails to attack when it should

    12. Mimicry When one organism copies another so it can benefit from what is has gained Example: Monarch and viceroy butterflies Pathogens use mimicry to: Escape attack Attack without being detected

    13. Novel Environment Factors Epidemics are caused by: Changed social conditions ( travel ) Modern technology ( Legionnaires Disease ) Overpopulated spaces ( TB) Best intentions ( improved sanitation )

    14. Summary The body is constantly at war with pathogens because each time a battle is won, there is another battle waiting to be fought.

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