AIDS full form is Acquired Immune Deficiency Syndrome. AIDS is a disease of human immune system caused by the infection with human immunodeficiency virus (HIV). The initial symptoms of this disease may be a brief period of influenza-like illness. AIDS is a disease which may progress for a long period of time without any symptoms. As the infection progresses, it interferes more and more with the immune system and makes the infected person too weak and thus susceptible to common infections like Tuberculosis, tumors, asthma, etc.
The HIV virus attacks on the T-cells in the immune system and makes your body so weak that it can be easily affected by bacteria, virus and fungi. In starting weeks, it can show symptoms like a headache, fever, sore joints and muscles, etc. When the infection spreads, the human immune system becomes weaker and loses its ability to fight the normal infections, diseases and cancers. AIDS is the extreme condition of this infection, i.e. a person infected with HIV will progress to AIDS, if not treated properly.