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The Biology of Disease. Infectious Agents Modes of Infection Germ Theory of Disease Defense Against Disease. Disease. Any change (other than an injury) that disrupts normal body functions Inherited/genetic Environmental factors Infectious agents (pathogens) Viruses Bacteria Protists
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The Biology of Disease Infectious Agents Modes of Infection Germ Theory of Disease Defense Against Disease
Disease Any change (other than an injury) that disrupts normal body functions • Inherited/genetic • Environmental factors • Infectious agents (pathogens) • Viruses • Bacteria • Protists • Fungi • Large parasites • Prions* Incubation period 3-14 days http://en.wikipedia.org/wiki/Dengue_fever. http://www.rcsb.org/pdb/101/motm.do?momID=103
Miasma, curses, and more “As long as (individuals) believed that microorganisms could arise from nonliving substances, scientists saw no purpose in considering how diseases were transmitted or how they could be controlled.” - Black, 1996 http://upload.wikimedia.org/wikipedia/commons/9/92/Cholera_art.jpg
Germ Theory of Disease • Refuted theory of spontaneous generation • Infectious disease is caused by germs (L. “to beget”) or pathogens. http://jvi.asm.org/content/77/11.cover-expansion
Development of the Germ Theory of Disease http://www.cdc.gov/features/handwashing/handwashing_a200px.jpg, http://www.accessexcellence.org/RC/AB/BC/images/lou_p.gif, http://news.bbc.co.uk/2/shared/spl/hi/pop_ups/06/magazine_local_treasures/html/1.stm, http://en.wikipedia.org/wiki/File:TB_Culture.jpg, http://www.extension.umn.edu/distribution/horticulture/dg1168.html
How do pathogens cause disease? http://www.morning-earth.org/Graphic-E/BIOSPHERE/Bios-Microbe-Image/M-Dfission.jpg, http://www.bioprepwatch.com/wp-content/uploads/2012/02/botulinum-toxin.jpg, http://www.trichinella.org/images/synopsis/21.1.jpg
Koch’s Postulates set of rules that is used to determine whether a specific pathogen is the cause of a specific disease http://4.bp.blogspot.com/_xURh3pkJN6E/TOlmOYp_8FI/AAAAAAAAABA/IcD4KNRSt4k/s1600/Kochs%2BPostulate.jpg
Discovering the cause of Lyme disease Allen Steere (Yale University) Lyme, Connecticut Observations • 39 children, several adults • Pain, joint inflammation • Summer-early fall • Insect bite then expanding skin rash Problem What is causing Lyme disease? http://upload.wikimedia.org/wikipedia/commons/0/01/Erythema_migrans_-_erythematous_rash_in_Lyme_disease_-_PHIL_9875.jpg
Using Koch’s Postulates http://commons.wikimedia.org/wiki/File:Ixodes_scapularis.png, http://www.lawestvector.org/LymeDisease.htm
Modes of Infection http://media.photobucket.com/image/vitruvian%20homer/austinheap/myspace/homer.gif?o=1
INNATE (NONSPECIFIC) IMMUNITY Rapid responses to a broad range of microbes ACQUIRED (SPECIFIC) IMMUNITY Slower responses to specific microbes External defenses Internal defenses Skin Phagocytic cells Humoral response (antibodies) Mucous membranes Antimicrobial proteins Secretions Inflammatory response Cell-mediated response (cytotoxic lymphocytes) Invading microbes (pathogens) Natural killer cells Two major types of defenses
Pathogen Awareness Project • 3D model of a chosen pathogen that affects Filipinos (pref. recycled materials, NO STYRO!) • Include a write-up with the following information on an A3 sized sheet: • Characteristics of the pathogen • Modes of transmission • Incubation period • Symptoms induced • Prevention/cure • Interesting trivia/statistics • Due Oct 15th, 12NN CAMIA 1,2 – Virus 3,4 – Bacteria 5,6 – Large parasite 7,8 – Virus 9,10 - Bacteria CHAMPACA 1,2 – Virus 3,4 – Bacteria 5,6 – Large parasite 7,8 – Virus 9,10 – Large parasite