Virusppt

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Virusppt

  1. 1. Viruses
  2. 2. Viruses- • Particles of nucleic acid, protein, & some lipids • Any of the microscopic particles that invade cells of plants, animals, fungi, & bacteria. • Often destroying the host cell. • Parasite • Virus= poison (Latin) • Examples: Colds, flu, and HIV
  3. 3. Inside A Virus• A core of genetic material• Capsid= A protein coat –Enables a virus to invade it’s host. –May be: • DNA • RNA
  4. 4. Living or Non-Living • Living- • Non-Living – Have DNA & – Crystallize RNA – Not cells – Heredity – Can’t make – Reproduce proteins – Evolve – Can’t reproduce w/out a host.
  5. 5. Structure Of A Virus • Core- –Nucleic acid –(DNA or RNA) • Capsid- –Protein coat surrounds core
  6. 6. Viral Reproduction • Steps in viral reproduction –Recognition –Attachment –Injection –Assembly –Lysis
  7. 7. Diseases Caused by Viruses • AIDS, Measles, Influenza • Pathogenic viruses are transmitted from host to host. –Air: Chicken pox –Water: Hepatitis –Insects: West Nile –See page 489
  8. 8. Fighting Viruses • Antibiotics can’t fight viruses • Drugs can’t destroy the virus w/out destroying the host • Viruses are fought with prevention using vaccines.
  9. 9. Vaccination • Only a healthy immune system can fight most viral diseases. • Vaccines build up immunity
  10. 10. Great Triumph’s • Eliminating small pox • 1796 vaccine discovered • 1949 last case in US • 1977 last case of small pox outside of
  11. 11. Filoviruses • Viruses that live without causing apparent harm • Causes disease only when infecting other animals • Among the most dangerous viruses
  12. 12. Filoviruses- cont • Cause –Hemorrhagic fever –Attack connective tissue –Massive bleeding –Morality rate 30- 90% –Ex: Ebola (1995) out break in Zaire
  13. 13. Vaccines DO NOT Protect AgainstAll Viral Diseases. • Vaccines are only effective against viruses w/non varying proteins on their surfaces. • Small pox, measles, & polio (same) • HIV, Cold, Flu (mutate)
  14. 14. Lysogenic Infections • Invades host & viral genetic material is injected & then fuses w/ host’s genetic material. • Results in many cells being infected with viral nucleic acid. • This type of virus has a “dormant period” • HIV is a Lysogenic virus.
  15. 15. LysogenicInfections
  16. 16. Lytic Infections • A virus enters a cell, makes copies of itself, and causes the cell to lysis. • Lysis= spreads the virus to other cells. • The cell can no longer tell its DNA from the virus’s DNA • Example Bacteriophage T4
  17. 17. Back To HIV (Lysogenic Virus) • How is it contracted – Sex (most common) – Blood transmissions/products – Drug use – Tattoos/piercings – Birth/breastfeeding – Healthcare settings
  18. 18. Preventing HIV (LIFE SKILL) • Abstinence or safe sex • Avoid drug & Alcohol use • Use caution in healthcare settings • Use caution when blood or other body fluids are spilled.

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