A condition of discomfort due to the internal disorders or invasion of germs or parasites is known as disease. People fall victim to diseases due to contaminated food, water, air, imbalance between work and rest, germs, lack of exercise, fatness, etc. Similarly, the diseases which are transmitted from one person to another are called Communicable diseases. The diseases which are not transmitted from one person to another are known as non-communicable diseases.
The diseases which can be transmitted from one person to another through air, animals, direct contact, water, soil etc. is known as communicable disease. Communicable diseases are caused by microorganisms like bacteria, virus, protozoa, fungi, etc. Some Communicable diseases are Tetanus, Tapeworm, Polio, Pneumonia, Kala azar, Malaria, HIV/AIDS, Syphilis etc.