1. VIRUSES And PRIONS

2. STRUCTURE A core nucleic acid - DNA or RNA
Nucleic Acid surrounded by a protein, called a capsid.

3. CLASSIFICATION
By genomes: DNA viruses, RNA viruses or retroviruses (any of a group of RNA viruses that insert a DNA copy of their genome into the host cell in order to replicate, e.g., HIV.)

4. Evolution of Viruses Two theories:
Evolved from bits of exogenous (escaped) from genes of larger organisms - dead bacteria?
Evolved from complex molecules proteins and nucleic acids before cells first appeared on earth
Coevolution between viruses and other organisms (can be mutualistic, parasitic, or commensal)

5. HOSTS required for viral reproduction
All types of organisms are hosts bacteria, fungi, humans, cows, bats, sheep, sponges, plants, etc.
Enter the host cell because capsid markers adhere to receptor cells of host
Highjack the host DNA and reproduce

7. Ebola Virus
Electron micrograph of Avian Flu Virus

8. Cycles of Viruses
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

9. VIRUSES CAN BE BAD or DEADLY Smallpox – viral infection
20-60% fatality rate overall
80% in children
Responsible for million deaths during the early 20th century
Eradicated in 1979 (Somalia)

10. Immune Response
Antigenic (protein) markers on capsid of the virus cause the immune system to react.
Immune system produces antibodies to attack the infection.
Once exposed, the immune system remembers the antigen – re-exposure will attack the virus before knowing you are sick

11. Edward Jenner and Vaccinations
Noticed milk maids had immunity to smallpox
Milkmaids were exposed to a less virulent (dangerous) form of the virus (cowpox)
Edward Jenner inoculated a boy with cowpox- the boy got sick, but recovered. He then inoculated the boy with smallpox – the boy did not get sick!
Beginning of modern day vaccinations

12. What is a Vaccine
Biological agent-improves immunity to a specific agent
Vacca- Latin for cow
Contains an agent that resembles the disease-causing microbe
Similar pathogen (cowpox for smallpox)
Killed virus (polio)
Weakened virus (measles, mumps)
Toxin (usually bacterial- diphtheria)

13. 1918 Flu Pandemic
I had a little bird its name was Enza I opened the window And in-flu-enza
-poem 1918

14. Definitions Endemic – disease regularly found in a population
Epidemic -a widespread occurrence of an infectious disease in a community at a particular time.
Pandemic - whole country or the world.
Virulence or pathogenicity– severity of a disease (for viruses:
a. Speed of replication,
b. ability to enter the host cell,
ability to evade the host immune system,
ability to lyse the cell)
epi = on, upon, above
Demic – relating to people or district
Pan=all
En= within

15. Definitions Continued
Vector -an 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)

16. 1918 Flu Pandemic (Spanish flu)
Killed more people than the Great War or World War I
38 million from WWI and approximately 50 million from 1918 flu
1/3 of the World Population Infected (500 million
Normally influenza has a 0.1% fatality rate, but 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

18. Prions Caused by a protein particle
transmissible spongiform encephalopathies (TSE) which are neurodegenerative diseases in mammals. Most commonly known- Mad Cow Disease, Scrapie, CJD, Kuru
Ceph- head –

19. Virus or Prion Project 20 points -
Creation of a colorful, neat, presentation, poster, essay, or movie about a virus.
Name of the Virus or prion – both common and scientific, if applicable, (chicken pox - varicella-zoster virus 
Picture of the virus or prion
Genome of the virus (RNA or DNA or protein if a prion)
Epidemiology of the Virus or prion (reservoir(s), vectors, spreading, fatality rate, risk factors etc.)
Mention any outbreaks of the viral disease with historical implications
Portion of the body infected.
Symptoms of infection
Preventions of infection
Treatments of infection
20 points -