Non-communicable disease Non-communicable disease A non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another. NCDs include Parkinson's disease, autoimmune diseases, strokes, most heart diseases, most cancers, diabetes, chronic kidney disease, osteoarthritis, osteoporosis, Alzheimer's disease, cataracts, and others. NCDs may be chronic or acute. Most are non-infectious, although there are some non-communicable infectious diseases, such as parasitic diseases in which the parasite's life cycle does not include direct host-to-host transmission. NCDs are the leading cause of death globally. In 2012, they caused 68% of all deaths (38 million) up from 60% in 2000. About half were
Mathematical modelling of infectious disease > 1, then each person on average infects more than one other person so the disease will spread; if "R" < 1, then each person infects less than one person on average so the disease will die out; and if "R" = 1, then each person will infect exactly one other person, so the disease will become "endemic:" it will move throughout the population but not increase or decrease. The basic reproduction number can be computed as a ratio of known rates over time: if an infectious individual contacts β other people per unit time, if all of those people