A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune diseases. In humans, "disease" is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, or death to the person afflicted, or similar problems for those in contact with the person. In this broader sense, it sometimes includes injuries, disabilities, disorders, syndromes, infections, isolated symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts and for other purposes these may be considered distinguishable categories. Diseases usually affect people not only physically, but also emotionally, as contracting and living with many diseases can alter one's perspective on life, and their personality.
Death due to disease is called death by natural causes. There are four main types of disease: pathogenic disease, deficiency disease, hereditary disease, and physiological disease.
Diseases can also be classified as communicable and non-communicable disease.
Famous quotes containing the word disease:
“What is the disease which manifests itself in an inability to leave a partyany party at alluntil it is all over and the lights are being put out?... I suppose that part of this mania for staying is due to a fear that, if I go, something good will happen and Ill miss it. Somebody might do card tricks, or shoot somebody else.”
—Robert Benchley (18891945)
“The peace loving nations must make a concerted effort in opposition to those violations of treaties and those ignorings of humane instincts which today are creating a state of international anarchy and instability from which there is no escape through mere isolation or neutrality.... When an epidemic of physical disease starts to spread, the community approves and joins in a quarantine of the patients in order to protect the health of the community against the spread of the disease.”
—Franklin D. Roosevelt (18821945)
“Man is an exception, whatever else he is. If he is not the image of God, then he is a disease of the dust. If it is not true that a divine being fell, then we can only say that one of the animals went entirely off its head.”
—Gilbert Keith Chesterton (18741936)