Disease

A pathologic condition that presents a group of clinical signs, symptoms, and laboratory findings peculiar to it and setting the condition apart as an abnormal entity differing from normal or other pathologic conditions.

Any condition of the body or mind, acute or chronic, that interferes with the person’s ability to function effectively under ordinary environmental circumstances. Literally, a lack of functioning. A may be either functional, organic, or both.

Literally ‘without ease”, may be defined as a failure of the adaptive mechanisms of an organism to counteract adequately, normally or appropriately the stimuli and stresses to which it is subject, resulting in a disturbance in the function or structure of some part of the organism. This definition emphasizes that disease is multi-factorial and may be prevented or treated by changing any of the factors. Disease is a very elusive and difficult concept to define, being largely socially defined. Thus, criminality and drug dependence presently tend to be seen as diseases, when they were previously’ considered to be moral or legal problems.

A condition that stops the body from functioning in the usual way.

An ailment of a plant caused by an infectious micro-organism, either fungal, bacterial or viral, or by a defect of environment such as a mineral deficiency in the soil, or an air pollutant. Infestations of most insects and other fauna are not regarded as diseases, except maybe for nematodes (eelworms) and some gall-producing insects.

An illness or disorder of the function of the body or of certain tissues, organs, or systems. Diseases differ from injuries in that injuries are the result of external physical or chemical agents.

A disorder with a specific cause and recognizable signs and symptoms; any bodily abnormality or failure to function properly, except that resulting directly from physical injury (the latter, however, may open the way for disease).

Any abnormality of bodily structure or function, other than those arising directly from physical injury.

A condition marked by subjective complaints, a specific history, and clinical signs, symptoms, and laboratory or radiographic findings. The concepts of disease and illness differ in that disease is usually tangible or measurable, whereas illness (and associated pain, suffering, or distress) is highly individual and personal. Thus, a person may have a serious but symptom-free disease (e.g., hypertension) without any illness. Conversely, a person may be extremely ill (e.g., with posttraumatic stress disorder) but have no obvious evidence of disease.

Harmful deviation from normal functioning of physiological processes (BMS). Deviation from normal functioning of physiological processes, of sufficient duration to cause disturbance or cessation of vital activity (APS). These two definitions are broad enough to allow malfunctions caused by nutritional deficiencies or excesses, toxic chemicals, adverse environmental factors, genetic anomalies etc., to be classed as diseases in addition to those caused by infective agents. The two classes of malfunction are sometimes classified as non-infectious and infectious diseases respectively; we recommend that the term ‘ disease ’ should apply only to malfunctions caused by pathogenic organisms or viruses, and that those caused by other factors should be termed disorders.