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1 Review Describe how bacteria cause disease Review How do viruses cause disease Relate Cause and Effect Are vaccines effective before or after infection-

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Presentation on theme: "1 Review Describe how bacteria cause disease Review How do viruses cause disease Relate Cause and Effect Are vaccines effective before or after infection-"— Presentation transcript:

1 1 Review Describe how bacteria cause disease Review How do viruses cause disease Relate Cause and Effect Are vaccines effective before or after infection- explain 2 Review Why are emerging disease of particular concern Propose a Solution What actions could your school take to help combat the evolution of “superbugs” and explain how these actions could make an impact

2 CH 20 VIRUSES AND PROKARYOTES 20.3 Diseases Caused by Bacteria and Viruses

3 Bacterial Diseases  Bacteria produce disease in one of two general ways  Destroy living cells and tissues of the infected organism  Release toxins (poisons) that interfere with the normal activity of the host cell.

4  Pathogens  Microorganisms that cause disease  All known prokaryotic pathogens are bacteria  No archaea are known to be pathogens.

5 Damaging Host Tissue  Tuberculosis  Inhaled into the lungs  Its growth triggers an immune response that can destroy large areas of tissue.

6 Releasing Toxins  Botulism  Deadly form of food poisoning.

7 Controlling Bacteria  Physical Removal  Disinfectants  Food Storage  Food Processing  Sterilization by Heat.

8 Physical Removal  Washing hands or other surfaces with soap under running water doesn’t kill pathogens  It dislodges both bacteria and viruses.

9 Disinfectants  Chemical solutions that kill bacteria  Can be used to clean bathrooms, kitchens, hospital rooms, and other places where bacteria may flourish.

10 Food Storage  Low temperatures slow the growth of bacteria and keep most foods fresher for a longer period of time than possible at room temperature.

11 Food Processing  Boiling, frying, or steaming can sterilize many kinds of food by raising the temperature of the food to a point where bacteria are killed.

12 Sterilization by Heat  Sterilization of objects such as medical instruments at temperatures well above 100° Celsius can prevent the growth of potentially dangerous bacteria.

13 Preventing Bacterial Diseases  Vaccine  Preparation of weakened or killed pathogens or inactivated toxins  Prompts the body to produce immunity to a specific disease  Immunity  Body’s ability to destroy pathogens or inactivated toxins.

14 Treating Bacterial Diseases  Antibiotics  Drugs used to attack a bacterial infection  Block the growth and reproduction of bacteria  Disrupt proteins or cell processes that are specific to bacterial cells  Do nothing against viruses.

15 Viral Diseases  Attack and destroy certain cells in the body, causing the symptoms of the associated disease  Cause infected cells to change their patterns of growth and development.

16 Preventing Viral Diseases  Vaccines.

17 Innovations in Vaccines  1769 Edward Jenner performs the first inoculation against smallpox, using the less harmful but similar cowpox virus.

18 Innovations in Vaccines  1880s Louis Pasteur develops vaccines against anthrax and rabies.

19 Innovations in Vaccines  1923 Albert Calmette and Camille Guerin develop a vaccine against tuberculosis.

20 Innovations in Vaccines  1950s Jonas Salk develops a polio vaccine that uses killed viruses. Albert Sabin develops a polio vaccine that uses weakened viruses.

21 Innovations in Vaccines  1981 A vaccine against hepatitis B that uses recombinant DNA gains government approval.

22 Innovations in Vaccines  2006 A vaccine against human papillomavirus, a virus known to cause certain cancers, gains approval.

23 Preventing Viral Diseases  Washing your hands frequently  Avoiding contact with sick individuals  Coughing or sneezing into a tissue or your sleeve, not into your hands.

24 Treating Viral Diseases  Cannot be treated with antibiotics  Antiviral drugs attack specific viral enzymes.

25 Emerging Diseases  An unknown disease that appears in a population for the first time or a well-known disease that suddenly becomes harder to control.

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27 More of a Threat  Changes in lifestyle and commerce  High-speed travel  Huge quantities of food and consumer goods are now shipped between regions of the world that previously had little contact with each other  Human populations that were once isolated are now in close contact with more developed parts of the world.

28  Emerging diseases are of particular concern because of their sudden appearance and resistance to existing control methods.

29 “Superbugs”  Bacteria resistant to whole groups of antibiotics and that transfer drug-resistant genes through conjugation  Result of natural selection.

30 Methicillin-resistant Staphylococcus aureus  MRSA  Skin infections  Especially dangerous in hospitals  Infection can be fatal for people in hospitals and nursing homes.

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32 New Viruses  Can jump species due to fast replication and high rate of genetic mutations  Evidence that this is how HIV moved from nonhuman primates into humans.

33  Gene shuffling among different flu viruses led to “bird flu”  Very similar to 1918 flu  Very slight genetic changes to jump to humans.

34 Prions  Misfolded proteins  Cause a chain reaction of misfolding in other normal proteins they contact.


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