A disease is any condition which results in the disorder of a structure or function in a living organism that is not due to any external injury. The study of disease is called pathology, which includes the study of cause. Disease is often construed as a medical condition associated with specific symptoms and signs. It may be caused by external factors such as pathogens or by internal dysfunctions, particularly of the immune system, such as an immunodeficiency, or by a hypersensitivity, including allergies and autoimmunity.
Before the curing of a strong disease, Even in the instant of repair and health, The fit is strongest; evils that take leave, On their departure most of all show evil.
William Shakespeare, King John (1598), Act III, scene 4, line 112.
Understanding how glacier sliding and iceberg calving contribute to loss in ice sheet models can improve predictions of global sea-level changes. This is hampered by the inaccessibility of a glacier's base and its calving front.