Illness and Disease

Physical health is an important aspect through which a person can lead a happy and active life. Despite all the precautions, a person can fall sick owing to diverse causes.

Often the term 'illness' and 'disease' are taken as synonymous, but there is a fine difference. Illness refers to the situation in which a person feels sick, though he may not have any disease; for example, feeling nausea, fatigue, headache etc., which may or may not need a treatment. On the other hand, disease is a sickness caused by other causes which in fact requires a treatment. A person can be ill without being diseased, and a person can be diseased without being ill. Thus, illness is a subjective condition.

A disease is a particular abnormal condition that negatively affects the structure or function of a body part or the whole body of a person or animal, not caused by an injury. It is construed as a medical condition that is associated with specific symptoms and signs. A disease is often used more broadly to refer to a condition that causes pain, dysfunction, distress, social problems or death to a person afflicted, or similar problems to those coming in contact with such a person.

A disease may be caused due to two main causes :

·         External causes, like pathogens; and

·         Internal causes like dysfunction of one or more body parts.

For example, influenza is caused due to external factors while allergy is caused due to internal dysfunction. Lifestyle diseases like diabetes are mainly internal causes. Disease can also be caused due to injury, for example, as a result of a fall or accident.

The four main types of diseases are :

·         Infectious diseases, like diarrhoea, fever.

·         Deficiency diseases, like rickets, anaemia.

·         Hereditary diseases, like fibrosis, hemochromatosis.

·         Physiological diseases, like asthma, diabetes.

Diseases can also be classified as communicable and non-communicable diseases. The deadliest diseases in humans pertain to the heart, brain and respiratory system. The study of disease is called pathology. Diseases are also classified on several other bases.