Human Immunodeficiency Virus

The name reflects the fact that the disease is caused by a virus that is specific to the human species. A virus is a kind of pathogen that reproduces by taking over the machinery of cells.

HIV is the virus that the overwhelming majority of researchers believe causes AIDS. There are still some researchers who remain unconvinced that HIV is the cause of AIDS. Others believe that HIV can only cause AIDS in the presence of some unknown cofactor. Because of the overwhelming evidence of the role of HIV in AIDS, many people refer to it alternatively as the "AIDS virus."