Good question! HIV is closely related to Simian Immunodeficiency Virus (SIV), a common and much less serious infection in wild populations of chimpanzees. Because of this relationship, we think that the virus jumped from chimps to humans (probably as humans began encroaching on chimpanzee territories in Africa in the 1950s or so, and possibly due to hunting and eating of chimps), underwent a few mutations to adapt to its new human environment, and thus became a successful, transmissable virus (HIV). The difference in the effect of the two viruses in the two different hosts (ie SIV in chimps and HIV in humans) is not understood and is an active area of research.
Good question! HIV is closely related to Simian Immunodeficiency Virus (SIV), a common and much less serious infection in wild populations of chimpanzees. Because of this relationship, we think that the virus jumped from chimps to humans (probably as humans began encroaching on chimpanzee territories in Africa in the 1950s or so, and possibly due to hunting and eating of chimps), underwent a few mutations to adapt to its new human environment, and thus became a successful, transmissable virus (HIV). The difference in the effect of the two viruses in the two different hosts (ie SIV in chimps and HIV in humans) is not understood and is an active area of research.
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