INFECTIOUS OR COMMUNICABLE DISEASES
These diseases are caused by various infectious or pathogenic organisms viz. bacteria, virus, protozoa and fungi. Infectious agents are spread through air, contaminated food, water, physical contact or vectors, e.g., smallpox, polio, dengue, cholera, tuberculosis, etc.
NON-INFECTIOUS OR NON-COMMUNICABLE OR DEGENERATIVE DISEASES
These are caused by malfunctioning of some organ or organ-system in the body. E.g., Heart attack, Arthritis, Hypertension, diabetes mellitus, etc.
DEFICIENCY DISEASES
These are caused due to deficiency of certain nutrients, minerals or vitamins, e.g., Kwashiorkor, Rickets, Goiter, Xerophthalmia, Beriberi, Scurvy, etc.
ALLERGIES
These diseases are caused due to hyper sensitivity of a person to some substances viz. drugs, dust, pollen, etc.
CANCER
This is caused due to uncontrolled and uncoordinated growth of normal cells or tissues, e.g., cancer of colon, Leukemia, etc.
ACUTE DISEASES
These diseases last only for a short duration, e.g., cold or cough.
