abbr.: AIDS; a collection of symptoms resulting from infection by a retrovirus (HIV-1 or HIV-2) that specifically attacks and destroys helper T lymphocytes, thereby impairing immunity and leading to a variety of other diseases (infections or neoplasms). Transmission is intrauterine, or by sexual contact, breast feeding, intimate contact with infected body fluids or tissues, and contaminated needles or syringes. The condition has reached epidemic proportionsaround the world. Treatment involves combinations of inhibitors of reverse transcriptase and HIV protease, and drugs to prevent microbial infections of brain, respiratory and alimentary tracts and vagina. See HIV.