HIV-1 is more virulent, easily transmitted and is the cause of the vast majority of HIV infections globally. Scientists generally accept that the known strains or groups of HIV-1 are most closely related to the simian immunodeficiency viruses SIVs endemic in wild ape populations of West Central African forests. Using HIV-1 sequences preserved in human biological samples along with estimates of viral mutation rates, scientists calculate that the jump from chimpanzee to human probably happened during the late 19th or early 20th century, a time of rapid urbanisation and colonisation in equatorial Africa. Exactly when the zoonosis occurred is not known. Some molecular dating studies suggest that HIV-1 group M had its most recent common ancestor MRCA that is, started to spread in the human population in the early 20th century, probably between and
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Saliva that does not contain visible blood is not considered to be a risk for HIV transmission. See below. Is the saliva of person at "window period" riskier than saliva of persons out of that period? I have found nearly all of your posts on "saliva" but it seems my following question has not been asked and answered before. I hope, you could help me to answer this question.