1. KEY CONCEPT Germs cause many diseases in humans.

2. Germ theory – states that microorganisms cause diseases.
proposed by Louis Pasteur
Disease-causing agents are called PATHOGENS.

3. There are different types of pathogens.
Bacteria - single-celled organisms.
Viruses - genetic material surrounded by a protein coat.
Fungi - multicellular or single-celled

4. Different PATHOGENS cause common infectious diseases.

5. Many methods are used to control pathogens.
Antiseptics kill pathogens OUTSIDE of the body.
Antibiotics kill pathogens INSIDE the body.

6. Pathogens can enter the body in different ways.
Indirect Contact does not require touching an infected individual.
Direct Contact requires touching an infected individual.