This is a pandemic we're still battling. Originating in Cameroon and first recognized as a disease in 1981, the earliest documented case is believed to be in 1959 in the Congo. As of 2011 at least 60 million people had been infected by AIDS and 25 million had died. Today its impact varies widely across the world—while in 2008 an estimated 1.2 million Americans had HIV, Sub-Saharan Africa alone was home to 22.9 million cases, with one in five adults infected. About 35.3 million people were believed to have HIV in 2012.