AIDS science definition

Short for acquired immune deficiency syndrome. An infectious disease of the immune system caused by an human immunodeficiency virus (HIV). AIDS is characterized by a decrease in the number of helper T cells, which causes a severe immunodeficiency that leaves the body susceptible to a variety of potentially fatal infections. The virus is transmitted in infected bodily fluids such as semen and blood, as through sexual intercourse, the use of contaminated hypodermic syringes, and placental transfer between mother and fetus. Although a cure or vaccine is not yet available, a number of antiviral drugs can decrease the viral load and subsequent infections in patients with AIDS.