PIP: AIDS is caused by the human T cell leukemia virus (HTLV) or lymphadenopathy associated virus (LAV) or human immunodeficiency virus (HIV). The latter name has been widely accepted. According to the WHO in 1988 there were 5 million infected persons. In Argentina, there were 300 AIDS patients and 30,000 infected people in 1989 and 60,000 in 1990. Obstacles to prevention of the spread of AIDS are: fear which causes some to conceal its existence; prolonged latency; complacency about future negative outcome; the lack of value of life among drug addicts; adolescent behavior of defiance and confrontation; militant denial by many of the possibility of contracting AIDS; and a criminally low level of measures to combat AIDS in the Third World. Primary prevention includes avoidance of contact with body fluids of an infected person submitting to a serological test if infection is suspected massive educational campaigns, study of subcultures such as drug addicts and adolescents, use of disposable needles and sterilization of all medical instruments use of condoms, and analysis of the blood of donated organs and blood for transfusion. Secondary prevention means making sure that seropositive patients undergo periodic medical checkups and receive medical attention when suspicious symptoms are detected and follow various steps to strengthen their immune systems. Tertiary prevention comprises psychological and psychopharmacological treatment of emotional distress to facilitate a less painful progress of the disease and to avert possible complications and relapses.