According to general theory, HIV-1, the most widespread type of liver that causes AIDS in people, comes from the chimpanzee SIVcpz virus. Researchers from the University of Alabama (USA) and the Montpellier Research Center (France) have now published data that corroborate this theory. After a genetic analysis of the viruses found in the excrement of chimpanzees in Cameroon, among others, it has been found that the SIVcpz viruses of the groups of chimpanzees living in isolation are very similar to GIB-1. In addition, the spread of HIV-1 has been investigated in its beginnings.