Many factors are responsible for the rising number of disabled persons and the relegation of disabled persons to the margin of society. These include: wars, and the consequences of wars and other forms of violence and destruction (poverty, hunger, epidemics, major shifts in population); a high proportion of overburdened and impoverished families; overcrowded and unhealthy housing and living conditions; populations with a high proportion of illiteracy and little awareness of basic social services or of health and education measures; an absence of accurate knowledge about disability, its causes, prevention and treatment, including stigma, discrimination and misconceived ideas on disability; inadequate programmes of primary health care and services; constraints, including a lack of resources, geographical distance, physical and social barriers, that make it impossible for many people to take advantage of available services; the channelling of resources to highly specialized services that are not relevant to the needs of the majority of people who need help; the absence or weakness of an infrastructure of related services for social assistance, health, education, vocational training and placement; low priority in social and economic development for activities related to equalization of opportunities, disability prevention and rehabilitation; low priority in social and economic development for activities related to equalization of opportunities, disability prevention and rehabilitation; industrial, agricultural and transportation-related accidents; natural disaster and earthquake; pollution of the physical environment; stress and other psycho- social problems associated with the transition from a traditional to a modern society; the imprudent use of medication, the misuse of therapeutic substances and the illicit use of drugs and stimulants; the faulty treatment of injured persons at the time of a disaster, which can be the cause of avoidable disability; urbanization and population growth; and other indirect factors.