Virus: Microlife Infectious Diseases Objective: you will be able to understand and explain how viruses attack and effect human cells

Intro: Infectious Disease Terms Disease which travels easily from one organism to another: Can also travel between species as well Pandemic – fast spreading international outbreak Epidemic- wide spread out break of disease at a specific location Asian Bird Flu 2007

Pathogen Pathogen- Any organism that causes diseases Carrier- any human giving a disease to another human Vector- any NON-HUMAN source of a disease being passed on to a human Diseases are primarily responsible for damaging individual cells, which causes us “sickness” symptoms” as cells break down Ex: sore throat

4 Forms of Pathogens Virus Bacteria Fungi Protists Bacteria

What are Viruses?

Viruses Non- Living: Do not require any energy to survive; No food/gas needs Extremely Small Organism made up of DNA or RNA and a Protein Coat : CAPSID Only capable of reproducing itself by “hi-jacking” another cell HIV Virus

3 Main forms of Viruses (Norovirus) /Polyhedral Bacteriophage (Filovirus)/ Rod Shaped )

All viruses have two types of infection cycles Lytic Cycle (Active) show signs of sickness immediately Lysogenic Cycle (Non Active) no illness creates “provirus cells” within body then becomes active

Lysogenic Cycle Shows no disease symptoms, may carry virus for years FACT: HIV can stay like this for over 10 YEARS!! 1. Virus attaches to host 2. Viral DNA integrates or combines with cells DNA; becomes a “provirus” cell 3. As cell splits and divides virus replicates with cell creating more “provirus” cells 4. Some trigger activates virus: become ill

Lytic Cycle Show disease symptoms Virus actively attacking cells 1. Virus attaches to host cell 2. Virus enters host cell 3. Virus destroys host cell’s DNA, replaces DNA with its own VIRAL DNA 4. “Hijacked” cell creates more Viral DNA and protein coating 5. Lysis-host cell ruptures and releases hundreds of new virus to attack more cells

Common Viruses Chicken pox Herpes HIV Ebola Epstein Bar (mono) Mumps Warts Influenza Hepatitis Common Cold

How we fight back: Vaccines