1 / 19

Understanding Defense Against Infectious Diseases

This presentation explores the various types of pathogens, including bacteria, viruses, fungi, and protozoa, and their impact on health. It covers how these microorganisms cause diseases such as food poisoning, flu, and malaria, and emphasizes the importance of antibiotics in fighting bacterial infections. It discusses the difference between bactericidal and bacteriostatic agents, how antibiotics work, and the growing threat of antibiotic resistance. Educational slides courtesy of Stephen Taylor illustrate these concepts effectively, highlighting the ongoing challenges in disease defense.

ace
Télécharger la présentation

Understanding Defense Against Infectious Diseases

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Defense against infections disease Ms. Fargo With some slides courtesy of Stephen Taylor

  2. Bacteria • Prokaryotes (no real nucleus) • Divide by binary fission • Can cause: • Food poisoning (e.g. Salmonella) • Ear and eye infections • Cholera, diarrhea http://en.wikipedia.org/wiki/File:Ericson_Type_II_Conjunctivitis.JPG

  3. Viruses • Acellular(non-living?) • Need a ‘host’ cell to carry out functions of life, including reproduction • Can have DNA or RNA • Mutate, evolve and recombine quickly • Cause: • Flu, HIV/AIDS, smallpox, measles, common cold, herpes, ebola The 1918 flu epidemic killed between 50 and 130 million people. http://en.wikipedia.org/wiki/1918_flu_pandemic

  4. Fungi • Eukaryotes, reproduce with spores • Cause: • Athlete’s foot, mould, ringworm • Allergic reactions and respiratory problems Image from: http://en.wikipedia.org/wiki/Athlete's_foot

  5. Protozoa • Simple parasites • Cause: • Malaria • Leishmaniasis • Toxoplasmosis Leishmaniasis image from: http://en.wikipedia.org/wiki/Leishmaniasis

  6. Bactericidal vs. Bacteriostatic • Bactericidal or fungicdal agents • Kill microbes • Bacteriostatic and fungistatic • Stop further growth • Don’t kill existing cells • It is thought that because the growth of the pathogen is stopped, the body’s immune system will be able to kill it.

  7. Antibiotics • Can be selectively toxic by targeting such features as the • Bacterial cell wall • 70 S ribosomes • This is the size of prokaryotic ribosomes • Enzymes that are specific to bacteria. • In this way, the human eukaryotic cells are unaffected.

  8. Antibiotics are ineffective against viruses! Over-use of antibiotics is accelerating the evolution of more harmful bacteria. We are running out of antibiotics that work and are selecting for diseases such as MRSA. http://www.youtube.com/watch?v=RedO6rLNQ2o • Antibiotics are designed to disrupt structures or metabolic pathways in bacteria and fungi: • cell walls and membranes • DNA synthesis (replication) • RNA polymerase • Translation • These do not exist or are very different in viruses, so the antibiotic will have no effect. Bacterial drug resisance, from Wiley Essential Biochemistry. Find out more here: http://www.wiley.com/college/pratt/0471393878/student/activities/bacterial_drug_resistance/index.html

  9. Antibiotics are ineffective against viruses! • Analyse the graph below. Over time, outline what has happened to: • The number of new approved antibiotics • The diversity of new approved antibiotics • Suggest reasons for your answers. Use the graph to write your own DBQ practice questions. Chlamydia trachomatis bacteria. Are you ready for the end of antibiotics? Guardian: http://gu.com/p/2jxgj The scariest graph you’ll ever see. Read the article by Maryn McKenna: http://www.wired.com/wiredscience/2011/02/not-many-antibiotics/

More Related