Infectious diseases are diseases caused by pathogens like viruses, bacteria, fungi, or protozoa, (which replicate inside the body) and can be passed from one person to another. Infectious diseases can be spread by several methods including through air, across surfaces and through touch.
Non-infectious diseases on the other hand, are restricted only to the sick person and do not spread from the patient to the healthy person. They are caused from:
a) lack of certain essential substances in our diet
b) degenration of tissues
c) uncontrolled growth of tissues
d) metabolic disorders
e) injury and damage to body parts