1. Health and Disease

3. Health: A state of complete physical, mental and social wellbeing and not merely the absence of disease.

5. Disease: Any change that impairs the function of an individual in some way and produces specific signs and symptoms. A disease is NOT a direct result of a physical injury.

6. Non-Infectious Disease: Not caused by a pathogen and cannot be transmitted from person to person via the environment. Infectious Disease: Is caused by a pathogen and can usually be transmitted from person to person via the environment.

7. Pathogen: A pathogen can be a – 1.A microorganism – eg Bacteria or Fungus 2.An agent – eg Virus or Prion 3.A multi-cellular organism – eg Parasitic Worm

8. Non-Infectious Diseases Not caused by a pathogen and cannot be transmitted from person to person via the environment.