1. What is an infectious disease?
An infectious disease is caused by the presence of a living organism in your body.

2. Pathogen: an organism that causes disease (Germ)
Host: organism that the pathogen invades.
Contagious: capable of spreading the disease to another person.
Susceptible: person who can potentially get the disease.
Immune: resistant to the pathogen.
Carrier: infected by pathogens but show no symptoms of the disease BUT can pass the disease to others.

3. 4 Kinds of Pathogens Bacteria: Strep throat, Tetanus
Viruses: Cold, Flu, HIV
Fungi: Athlete’s Foot, Ringworm
Protist: Malaria, Dysentery

4. How Pathogens Are Spread
Infected People: direct physical contact
Soil, Food, and Water: occur naturally ex)Cholera
Contaminated Object: towels, rusty nail ex)Tetanus
Animals: can be infected with the disease (Rabies) or serve as a vector: organism that can transmit the disease but is not infected (Malaria)

5. Conditions Favorable to Disease
Epidemic: widespread outbreak of an infectious disease in which many people are infected at the same time.
Overcrowding
Lack of Sanitation
Climate (Warm, Wet)
Contaminated Water Supply