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Infectious Diseases

Infectious Diseases. Unit 5. 5.1 Key Terms & Essential Questions. How are infectious diseases spread through a population? What is aseptic technique? How can an unknown sample of bacteria be identified? How does the immune system function to protect the human body from foreign invaders?.

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Infectious Diseases

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  1. Infectious Diseases Unit 5

  2. 5.1 Key Terms & Essential Questions • How are infectious diseases spread through a population? • What is aseptic technique? • How can an unknown sample of bacteria be identified? • How does the immune system function to protect the human body from foreign invaders?

  3. Infectious diseases • Caused by the entrance and reproduction of an infectious agent in a body • Bacteria or virus • The medical examiner who performed Anna Garcia’s autopsy pulled copies of Anna’s medical records before proceeding with the autopsy. Interestingly, the medical examiner discovered that Anna had been hospitalized just ten days prior to her death for a sickle cell crisis and subsequently was treated for an infection that was most likely acquired during her hospital stay. The medical examiner then noted that a page of the medical history is missing. Throughout this lesson, YOU will play the role of medical detectives in order to investigate Anna’s mystery infection. Ultimately, YOU will need to identify the exact pathogen, or infectious agent, responsible for Anna’s illness.

  4. Influenza Outbreak (1918-1919)Death and Devastation • Deadliest in modern history • More died from the flu than from World War I • More than 25% of the U.S. population became sick • 675,000 Americans died during the pandemic • All age groups were affected, not just the young and elderly

  5. Spread of the Disease • First observed in Europe, the U.S. and parts of Asia • Swiftly spread around the world • Highest impact was along shipping and trade routes • Spread quickly due to worldwide travel of troops returning from WW1 • Estimates put the worldwide death toll at 21,642,274

  6. Cause of Death • Extensive hemorrhaging in the lungs • Patients literally drowned in fluids • Researchers later discovered what made the pandemic so deadly • In many victims, the influenza virus had invaded their lungs and caused pneumonia

  7. Prevention • Quarantine of infected individuals • Mandatory use of face masks by all individuals when out in public

  8. Public Service Announcements: An important part of prevention

  9. Public Service Announcements: An important part of prevention

  10. How are the diseases spread? • From person-to-person • Potential to become epidemics. • Flu, colds, measles, small pox, and the plague • From animal-to-person • Zoonotic • Rabies, brucellosis (also known as undulant fever), staphylcoccosis, and streptococcosis. • Through contaminated food, soil, water, or other material • By disease vectors including: • Mosquitoes • Fleas • Ticks

  11. How are people infected? • Contact with infected body fluids. • Mucous from a cough or sneeze, blood, feces • Air, water, or food borne infectious agent • Contaminated surface • Door knob • Telephone

  12. Long term effects of infection • Bacterial and viral infections can damage the heart tissue • Viral infections can cause nerve damage • suspected as a factor in the development of chronic neuromuscular syndromes including • Multiple sclerosis • Fibromyalgia • Chronic Fatigue Syndrome • Both can lead to death

  13. 5.1.2: Infectious Disease Agents • Begin your detective work by exploring the different types of pathogens as well as examining specific examples of each type in order to identify what is plaguing Anna • bacteria • viruses • fungi • protozoa • helminthes • prions • Investigate a variety of diseases caused by infectious agents and use this information to determine the tests you will need to perform in the subsequent activities to fill in the missing pieces from Anna’s medical history

  14. What are Viruses? • Non-living particles that infect cells and cause disease • Requires antivirals, antibiotics have no effect • Very specific • Must be able to attach to a cell to infect it • Contain genetic material that mutate • Causes a change in the characteristics of the virus • Allowing the virus to attach to new types of cells

  15. Viruses are not ALIVE!!!

  16. How Viruses Work NPR video

  17. What are bacteria? • All are unicellular • All are prokaryotic - cells that lack nucleus (no nuclear envelope) (PRO = NO nucleus) • All have cell walls • Reproduce via fission or budding • Can live in both aerobic (with O2) and anaerobic (without O2) environments • Much larger than viruses • Usually have one of three different cell shapes: coccus, sprillum, bacili

  18. Cytoplasm Genetic Material Cell Wall Cell Membrane Flagella Endosymbiotic theory

  19. Coccus (Sphere-shaped) Ex: Streptococcus Bacilli (rod-shaped) Ex: Lactobacillus Spirillum (Spiral-shaped) Ex: Spirillium

  20. What shape? bacillus spirillum coccus spirillum coccus bacillus

  21. 5.1.2: Infectious Disease Agents:

  22. Disease Cards

  23. 5.1.1 Contagious: Are you patient zero?

  24. Outbreak: Anatomy of an epidemic

  25. Infection & Disease • Pathogen- infectious agent responsible for disease • Infection- pathogen invades and begins growing within a host • Disease- occurs if and when the invasion and growth of a pathogen impair bodily functions • To cause diseasepathogens must • Enter the host body • Adhere to specific cells • Invade and colonize tissues • Inflict damage

  26. Enter through openings to the body: mouth, eyes, nose, genital openings, breaks in the skin • Cause disease by • Destroying cells of infected organisms by breaking the cells down for food • Releases toxins (poisons) which destroy cells of infected organism • Must have access to new hosts to spread

  27. Highly contagious and virulent

  28. 5.1.3: Isolating Bacteria • Patient samples contain a mix of bacteria • Bacteria grow in groups called colonies • On a growth media called agar • Isolation of individual colonies is necessary to study all of the possible pathogenic organisms for identification tests

  29. 5.1.3 Colony Morphology • http://www.microbelibrary.org/images/shoeb/colonial%20morphology.html • Shape • Margin • Optical Properties • Pigment • Elevation • Texture

  30. Colony Shape

  31. Colony Margin

  32. Optical Properties

  33. Colony Pigment Colony Elevation

  34. Colony Texture • Soft • Granular • Tenacious • Mucoid

  35. Bacterial Isolation • A sample of each colony type streaked onto an agar plate to physically separate the colonies • You will isolate bacterial colonies from four samples, including Anna’s, and then complete a gross examination of the colonies from Anna’s sample

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