1. VIRUSES And PRIONS

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

3. Infection and Reproduction
DNA or RNA -into host DNA
Uses host proteins (enzymes, etc.) to reproduce
Once reproduced to a certain level – burst (lyse) & infects 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 to reproduce All organisms may be hosts
Usually specific hosts

5. Cycles Lytic Cycle –lyse cells shortly after infection influenza, HPV
Lysogenic Cycle- remain dormant (“hidden”) in the cell
- a trigger causes the viruses to begin growing and move to lytic cycle (bursting) to release more viral particles. (Shingles, HIV)
Amoeba Sisters Summary
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6. VIRUSES Some deadly Smallpox – viral infection
20-60% fatality rate overall
80% in children
Responsible for million deaths during the early 20th century
Eradicated in 1979

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) have 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 (memory)
Vacca- Latin for cow
agent that resembles the disease-causing microbe
immune response – if 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 Enza I 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 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

15. Prions protein particle
transmissible spongiform encephalopathies (TSE) which -neurodegenerative diseases.
Most commonly known- Mad Cow Disease, Scrapie, CJD, Kuru
Ceph- head –