Researchers proclaim they found a type of SIVcpz that is almost identical to HIV

On 4 February 1999 a  group of researchers from the University of Alabama proclaimed that they had found a type of Simian Immunodeficiency Viruses (SIVcpz) that was almost identical to HIV-1. This particular strain was identified in a frozen sample taken from a confined member of the sub-group of chimpanzees known as Pan Troglodytes, which were once widespread in west-central Africa. The team of researchers, led by Paul Sharp of Nottingham University and Beatrice Hahn of the University of Alabama, made the finding during the course of a 10-year long study into the origins of the virus. Researchers claimed that the sample proved that chimpanzees were the source of HIV-1 and that the virus had at some point crossed species from chimpanzees to human beings. Their ultimate findings were published two years later in Nature magazine.  In this article, they concluded that wild chimps had been infected concurrently with two different simian immunodeficiency viruses which had "viral sex" to form a third virus that could be spread on to other chimps and, more importantly, was capable of infecting humans and causing AIDS.