Health is a state of physical, mental and social well-being.
The health of an individual is dependent on his/her physical surroundings and his/her economic status.
Diseases are classified as acute or chronic, depending on their duration.
Disease may be due to infectious or non-infectious causes.
Infectious agents belong to different categories of organisms and may be unicellular and microscopic or multicellular.
The category to which a disease-causing organism belongs decides the type of treatment.
Infectious agents are spread through air, water, physical contact or vectors.
Prevention of disease is more desirable than its successful treatment.
Infectious diseases can be prevented by public health hygiene measures that reduce exposure to infectious agents.
Infectious diseases can also be prevented by using immunisation.
Effective prevention of infectious diseases in the community requires that everyone should have access to public hygiene and immunisation.