1. Viral Diseases
How do vaccines work?

2. How do viruses enter our body?
Must first pass through skin
Can enter mucous membranes or cuts
Makes its way to target cell

3. Examples of Viral Infections
Common cold – infects mucous membranes

4. Examples of Viral Infections
Influenza
Can jump between species
Proteins on surface change rapidly requiring new vaccines every year

5. Examples of Viral Infections
HIV
Retrovirus – contains RNA and uses it to make an DNA copy
Lysogenic infection

6. Vaccines prevent viral infections
Viral infections can lead to epidemics or pandemics
Epidemic – rapid outbreak affecting many people in localized area
Pandemic – rapid outbreak across many areas
Vaccines are used to stop the spread of the disease
Made from same virus they are protecting against, but it is a weakened version
Immune system recognizes and reacts upon re- exposure