Acquired Immunodeficiency Syndrome (AIDS) is caused by the human immunodeficiency virus (HIV) that causes progressive impairment of cellular immunity. The virus is transmitted through exposure to infected blood (via, for example, shared needles and occupational exposure of medical personnel) and blood products, sexual contact, and breastfeeding when the mother is HIV positive. The risk of developing the disease after exposure to infected body fluid is determined by the type and volume of fluid, the level of viremia in the person with HIV, and the integrity of the exposed site.
Certain risk factors, such as menstruation, uncircumcised male partner, sharing of equipment for drug administration, and deep injuries, increase the chances of developing AIDS. The primary infection causes fever, headache, diarrhea, and oral and genital ulceration. Antiretroviral therapy (ART) became available as a treatment to suppress the replication of viruses in 1996. Since then, HIV has transformed from a fatal progressive disease to a chronic manageable disease. Some commonly used antiretroviral drugs are zidovudine, abacavir, nevirapine, and etravirine.