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VIRUSES And PRIONS

VIRUSES And PRIONS. STRUCTURE. DNA strand or RNA strand Covered by a Capsid Capsid (protein covering). Function of Structures. DNA or RNA incorporate into host DNA Use the host proteins (enzymes, etc.) to reproduce Once reproduced to a certain level – burst to infect other cells

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VIRUSES And PRIONS

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  1. VIRUSES And PRIONS

  2. STRUCTURE • DNA strand or RNA strand • Covered by a Capsid • Capsid (protein covering)

  3. Function of Structures • DNA or RNA incorporate into host DNA • Use the host proteins (enzymes, etc.) to reproduce • Once reproduced to a certain level – burst to infect other cells • Capsid (covering) – identify host to attach and enter cells • Capsid – also is portion that immune system identifies to attack the virus.

  4. HOSTS • required for reproduction • All types of organisms may be hosts • Usually specific hosts

  5. Cycles • Lytic Cycle – infect, reproduce, and lyse (break-open the cell) – influenza, HPV • Lysogenic Cycle- infect, remain dormant (“hidden”) in the cell, a trigger will cause the viruses to begin growing and go through the lytic cycle (bursting) to release more viral particles. (Shingles, HIV) • Amoeba Sisters Summary • https://s-media-cache-ak0.pinimg.com/originals/e2/0f/50/e20f508e9c5a5fcd5eb7d02f0600c823.jpg

  6. VIRUSES • Some deadly • Smallpox – viral infection • 20-60% fatality rate overall • 80% in children • Responsible for 300-500 million deaths during the early 20th century • Eradicated in 1979 (Somalia)

  7. Immune Response • Antigenic (protein) surface markers on capsid cause an immune response • Immune system produces antibodies to attack the infection. • Memory: If re-infected the immune system remembers the antigen & will attack the virus before you get sick.

  8. Edward Jenner and Vaccinations • milk maids had immunity to smallpox • Hypothesis: Milkmaids exposed to a less virulent (dangerous) form of the virus (cowpox) had immunity to smallpox. • injected a boy with cowpox- the boy got sick but recovered. • then injected the boy with smallpox – the boy did not get sick!

  9. How vaccines work • Vacca- Latin for cow • Contains an agent that resembles the disease-causing microbe • Causes an immune response – if get exposed to virus the immune system remembers it and destroys the virus before the host gets sick.

  10. 1918 Flu Pandemic I had a little bird its name was EnzaI opened the window And in-flu-enza -poem 1918

  11. Definitions • Endemic –regularly found in a population • Epidemic -widespread occurrence at a certain time. • Pandemic - world. • Virulence /pathogenicity– severity epi = on, upon, above Demic – relating to people or district Pan=all En= within

  12. Definitions • Vector –(carrier) organism that transmits a disease or parasite • Reservoir (disease) – host- infectious agent normally lives and multiplies • Zoonotic Infections- disease that can be transmitted from animals to people  (rabies, SARS, influenza, Lyme disease)

  13. 1918 Spanish flu • Killed > Great War or World War I • 38 million from WWI/50 million from 1918 flu • 1/3 of the World Population Infected (500 million) • Normally influenza has a 0.1% fatality rate, but 1918 had increased virulence because of new mutations- all those that may have been immune with a slight mutation were not. • Economic impacts and impacts to the war effort

  14. Prions • protein particle • transmissible spongiform encephalopathies (TSE) which -neurodegenerative diseases. • Most commonly known- Mad Cow Disease, Scrapie, CJD, Kuru • Ceph- head – https://www.youtube.com/watch?v=ujK7KiLt0s8

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