1.Unit 3: It's a Small World Microorganisms andDisease

2. What Do You Think?When you catch a cold, what is it that infects your body? 3. Germ Theory Idea that microorganisms can and are the cause of many diseases Originally proposed back in 1020 A.D. and built upon by many different scientists Microorganisms were first observed by Anton van Leeuwenhoek Louis Pasteur, a French chemist, helped to disprove another competing theory and his 4. Germ Theory Joseph Lister, an English surgeon, was one of the 1st to realize the importance of germ theory He used chemicals on wounds to kill germs Also made sure that everything that touched his patients was washed in a chemical solution so that it was free of germs 5. Antiseptics = Disinfectants? Antiseptics are for use on people Disinfectants are for use on objectsand surfaces. 6. Robert Koch 1st to actually demonstrate that microorganisms do cause disease Studied anthrax While investigating the disease, he developed a set of rules for proving that a microorganism is the cause of a specific disease. These rules are called Kochs postulates and they are a good example of the scientific method. 7. Kochs postulates1. The microorganism must be foundin abundance in all organismssuffering from the disease, but notin healthy organisms.2. The microorganism must beisolated from a diseased organismand grown in pure culture. 8. Kochs postulates3. The cultured microorganismshould cause disease whenintroduced into a healthy organism.4. The microorganism must bereisolated from theinoculated, diseased experimentalhost and identified as beingidentical to the original agent. 9. List as many different diseases asyou can. 10. Diseases 2 types of disease Noninfectious diseases: diseasesthat are not spread from one personto another Infectious diseases: diseases thatcan be passed from one living thingto another 11. What causes disease? Noninfectious diseases can becaused by many different factors.Smoking, lack of physicalactivity, and a high-fat diet cangreatly increase a persons chancesof getting many noninfectiousdiseases. Infectious diseases are caused bypathogens 12. Think, Pair, Share How is an infectious diseasedifferent from a noninfectiousdisease? 13. Did You Know? Before the mid-1800s, doctors and surgeons rarely washed their hands before surgery. This was because pathogens were not known about Many people believed that if someone got a disease it was because they were being punished 14. Pathways to Pathogens Look at p.S68 in your textbook.What are two ways that infectiousdiseases are spread? 15. Pathways to Pathogens There are many ways pathogenscan be passed from one person toanother. Being aware of them canhelp you stay healthy.1. Through the air: a single sneeze releases thousands of tiny droplets of moisture that can carry pathogens 16. Pathways to Pathogens2. Contaminated objects: person whois sick may leave bacteria orviruses on objects such asdoorknobs, keyboards, drinkingglasses, towels, or combs.3. Person to Person: may becomeinfected with some illnesses bykissing, shaking hands, or touchingthe sores of an infected person 17. Pathways to Pathogens 4. Animals: some pathogens arecarried by animals; humans can getringworm from handling an infecteddog or cat. Also, ticks can carrybacteria that cause Lyme disease.5. Food and water: water lines canbreak or treatment plants canbecome flooded allowingmicroorganisms to enter the public 18. Brain Food In developing countries, 80% ofdiseases are related tocontaminated drinking water. 19. Inferring Relationships Why might the risk of infectiousdisease be high in a community thathas no water treatment facility? 20. Checkpoint Jackie cut up raw meat on herkitchen counter. If her brothermakes a sandwich on the samecounter later, how could he come incontact with a pathogen? 21. Causes of Infectious Disease Bacteria are one kind ofmicroorganism that can cause aninfectious disease.Can affect the human body in different ways Bacteria can kill cells and tissues Other bacteria do damage by releasing toxins 22. Causes of Infectious DiseaseViruses Smallest of disease-causing microorganisms Even the largest virus can just barely be seen with a light microscope Common cold, influenza, warts, rabies, AIDS,Ebola 23. Causes of Infectious Disease Protozoans Malaria and sleeping sickness Fungi Cells of the fungus enter the body through the digestive or respiratory system Athletes foot and ringworm 24. Think, Pair, Share What are the four causes ofinfectious disease? Which cause involves toxins? Which cause is at fault when youhave the flu?