Human immunodeficiency virus (HIV) is a virus that affects humans and can lead to acquired immunodeficiency syndrome (AIDS). This disease was first recognized on December 1, 1981. Since then, the World Health Organization (WHO) estimates that 25 million people have been killed by AIDS.
According to the Center for Disease Control (using figures from 2006), there were an estimated 1,106,400 adults and adolescent that were HIV-infected people in the United States. Around 1/4 of these people were unaware they have the disease.
HIV is a lentivirus, which is a member of the retrovirus family. The virus can lead to a condition where the immune system begins to fail in humans infected with the disease. HIV attacks the immune system by destroying specific white blood cells (T cells or CD4 cells). Without these cells, the immune system is unable to fight diseases.
There have been many treatments for HIV developed, but there is no know cure.
For more information