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Bacterial & viral Disease

Bacterial & viral Disease. Biology 20.3. Pathogen defined. Yellow fever virus. “A bacterium, virus, or other micro- organism that can cause disease.” Bacteria & viruses are some of the most common. Clostridium botulinum bacteria. Bacteria cause disease!.

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Bacterial & viral Disease

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  1. Bacterial & viral Disease Biology 20.3

  2. Pathogen defined Yellow fever virus • “A bacterium, virus, or other micro- organism that can cause disease.” • Bacteria & viruses are some of the most common Clostridium botulinumbacteria

  3. Bacteria cause disease! • Pasteur’s “swan-neck flask” experiment • http://education-portal.com/academy/lesson/the-germ-theory-of-disease-definition-louis-pasteur.html#lesson (7’)

  4. Bacteria cause disease by… • Damaging host tissue • Ex: TB (tuberculosis – caused by Mycobacterium tuberculosis) • Releasing toxic chemicals that disrupt homeostasis • Ex: Botulism (Clostridium botulinum) Hypotonia due to botulism

  5. FYI – how people use botulism for “good”

  6. Bacteria: • Most bacteria are harmless …beneficial, actually, as you know! • Bacterial infections are NOT fun & control measures are needed: • Physical removal: ex- washing hands; dislodges pathogens • Disinfectants: ex- chemicals that kill used in hospitals, bathrooms, kitchens, etc. • Food storage: ex- refrigerator with low temps helps slow growth • Food processing: ex- boiling, frying, steaming with high temps kill many bacteria • Sterilization by heat: ex- autoclaving medical instruments at temperatures over 100◦C prevents growth

  7. Preventing disease with vaccines • In SIMPLE terms, how do they work? • https://www.youtube.com/watch?v=SduMbjW2V9A (1.59’) • Why should we care? • https://www.youtube.com/watch?v=JZvpF6gaGH4 (3.51’) • Herd immunity? • Is it enough? • Is it socially responsible? • We’ll come back to this…

  8. Antibiotic action • 1. Interfere with bacterial cell wall synthesis2. Disrupt bacterial protein synthesis at the ribosome 3. Inhibit function of enzymes involved in DNA synthesis by masquerading as a natural component of the synthetic machinery

  9. How do viruses cause disease? …review;) Poliomyelitis virus • Disrupting body’s normal homeostasis • Attack & destroy body’s cells (ex: polio & nerve cells=paralysis) • Force cells to change growth & development and potentially lead to cancers (ex: HPV & cervical epithelial cells= cervical cancer) Human Paplilomavirus

  10. Prevention w/ protection is the • Simple forms of protection can go a LOOONG way! • http://abcnews.go.com/WNT/video/best-sneeze-22258478 BREAK THE CYCLE!!

  11. Vaccine controversy? NPR’s “All Things Considered” 7/14/11 http://www.npr.org/2011/01/09/132735944/as-the-facts-win-out-vaccinations-may-too (8.23’)

  12. When prevention fails… • Antibiotics do NOT work for viral infections • AND taking an antibiotic for a virus can lead to antibiotic resistance (i.e. SUPERBUGS – yikes!)

  13. Emerging Disease • Defined: “An unknown disease that appears in a population for the first time or a well-known disease that suddenly becomes harder to control” • Why such a threat? • Changes in lifestyle – isolation not as likely • High-speed travel – remember “Hot Zone”?? • Commerce – increase shipping worldwide • Little to no resistance against them • Methods of control not developed yet

  14. Evolution of disease • Replication/“gene shuffling” happens sooooooooo quickly (e.g. SUPERBUGS) • Viruses can switch host species (ex: AIDS) • Prions (ex: mad cow and other brain wasting diseases)

  15. No matter what…best to stay educated;)

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