The pandemic caused by the human immunodeficiency virus, which crossed from primates to humans in central Africa around the early twentieth century and, after recognition in 1981, killed more than forty million people worldwide. HIV destroys the immune system and, untreated, leads to AIDS — once almost always fatal, now manageable with antiretroviral therapy. The disease's path was shaped less by biology alone than by stigma, poverty, political neglect, and the deeply unequal question of who could afford the drugs that saved lives.
A virus crossed from chimpanzees to humans in central Africa around a century ago, and in barely a generation it killed more than forty million people. The world was slow to notice. When AIDS was recognized in 1981, it was first seen as a disease of gay men, and the stigma that followed shaped everything: who got blamed, who got cared for, and who got left to die. By the late 1990s, medicine had learned to control HIV. But the drugs that turned it into a survivable condition in rich countries stayed priced out of reach in Africa, where most of the dying was. The disease exposed a hard truth about plagues: their path is cut not only by biology, but by stigma, money, and politics.