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INFECTIOUS DISEASE

INFECTIOUS DISEASE. What is a disease?. A disease is any change, other than an injury, that disrupts the normal functions of the body. What can cause this change? Genetics Materials in the environment Pathogens . What is a pathogen?.

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INFECTIOUS DISEASE

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  1. INFECTIOUS DISEASE

  2. What is a disease? • A disease is any change, other than an injury, that disrupts the normal functions of the body. • What can cause this change? • Genetics • Materials in the environment • Pathogens

  3. What is a pathogen? • Disease-causing organisms are called pathogens, which literally means “sickness makers.” • Diseases caused by pathogens are generally called infectious disease because they enter, or infect, the body of the organism that gets sick.

  4. What causes infectious diseases? • People used to believe curses, evil spirits, or night vapors caused diseases. • In mid 1800s Louis Pasteur and Robert Koch provided another explanation – THE GERM THEORY OF DISEASE • This theory concluded that infectious diseases were caused by microorganisms, more commonly known as germs.

  5. How are infectious diseases different? • Diseases are change in the normal functions of the body. • They may or may not be infectious diseases. • Infectious diseases are diseases that are caused by the invasion of a host by an agent whose activities harm the host’s tissues (that is it causes the disease) and can be transmitted to other individuals (that is they are infectious).

  6. How were diseases identified? • Once it was believed that pathogens (germs) were causing diseases, Koch developed a series of guidelines still used today to identify the microorganisms that cause specific diseases. • These rules are known as Koch’s postulates.

  7. Koch’s Postulate • Find pathogen in sick hosts, but not healthy ones • Isolate and grow pathogen • When pathogen is placed in new host, it should cause same disease as original host • Very same pathogen should be isolated

  8. What are pathogens? • Pathogens are also known as infectious agents. • Infectious Agents include: • Bacteria • Viruses • Protozoa • Helminth (Worms) • Fungi • Prion

  9. Very small unicellularprokaryotes (remember what this means?) that have cell walls containing peptidoglycans (peptide = protein, gylcan = carbohydrate) Example Diseases: Anthrax Botulism Tuberculosis Typhoid Treatment for bacterial diseases: Vaccines Antibiotics Bacteria

  10. Bacteria 1 cell • Reproduce through Binary fission – one cells splits into two cells 2 cells

  11. Bacteria • Classified into three types based on their shape • Bacillus – Rod Shaped • Coccus – Sphere Shaped • Spirillum – Spiral Shaped

  12. Small particle composed of nucleic acid enclosed in a protein Can only reproduce by infecting living cells CANNOT BE TREATED WITH ANTIBIOTICS Viral Diseases: AIDS Measles Hepatitis Ebola Treatment: Vaccines Antiviral Viruses

  13. Multicellular microorganism They live on your hair, nails and outer skin layers Fungal Diseases: Athlete’s Foot Ringworm Treatment: Antibiotics Antifungals Fungus

  14. Simple, unicellular eukaryote (remember what this means?) Protozoan Diseases: Chagas Amoebic Dysentery Malaria Treatment: Antibiotics Protozoa

  15. Multicellular worms Examples: Pinworm Roundworm Tapeworm Hookworm Treatment: Antihelminths Helminth (Worm)

  16. Small particle composed only of protein Only passed through food Example Diseases: CJD (mad cow disease) Scrapie Treatment: NO KNOWN TREATMENT Prion

  17. How do diseases spread? • Direct Contact • Coming into contact with someone that has the disease • Person to Person: most common; direct transfer of pathogen from one person to another • Animal to Person: animal waste; being bitten or scratched • Vector = Animals that carry disease-causing organisms • Doesn’t cause the disease, just carries it • Examples: Mosquitoes, Ticks, Flea, Mouse • Mother to unborn Child: through the placenta mothers can pass germs to her unborn baby

  18. How do diseases spread? • Airborne • Some germs can travel as small particles or through water vapor droplets • Indirect Contact • Many germs can linger on inanimate objects (table top, doorknobs, sink handles)

  19. How do diseases spread? • Vehicles • Through food or water • Allows the disease to spread to many people through a single source • Vectors • Through animals that carry the disease • Mosquitos, Ticks, Fleas

  20. How can you prevent diseases from spreading? • Wash your hands often. • Get vaccinated. • Use antibiotics sensibly. • Don’t eat foods with antibiotics in them. • Don’t take antibiotics when you don’t need them. • Don’t use antibacterial soap. • Stay at home if you have signs and symptoms of an infection. • Be smart about food preparation. • Disinfect the 'hot zones' in your home. • Kitchens, bathrooms • Practice safe sex. • Don't share personal items. • Toothbrushes, dining utensils • Keep your pets healthy.

  21. How do you categorize diseases?(This should sound familiar!) • Infectious Agent • bacteria, virus, protists, helminth, fungi, prion • Treatment • Prevention • History of Disease • Transmission • Airborne, direct/indirect contact, vehicles, vectors

  22. Categorizing Diseases, History Endemic • Disease has been around for a while and the rate of incidence (number of people with the disease) is consistent

  23. Categorizing Diseases, History Emerging • Diseases that have developed in recent history • Draw Graph Re-Emerging • Diseases whose incidence (number of people with disease) had remained relatively stable, but then increased in the past 20 years • Draw Graph

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