Neil Katz poses the question for CBS News:
The precursor to H.I.V., the virus that causes AIDS, may be older than you think. Way older.
According to new research, simian immunodeficiency virus (S.I.V.) has been in monkeys for millennia, potentially putting humans at risk for the last 32,000 years and possibly much longer.
And yet, for all that time, humans didn’t get sick in mass. Only in the 20th century did H.I.V. become a global scourge that has claimed 25 million lives.
According to the New York Times, for as long as monkeys have had S.I.V., humans who have butchered them have put themselves at risk of infection from a mutated form. But because the infected people in Africa were fairly isolated, the chances for an epidemic were small. That changed, some theorize, with the explosive growth of African cities and wide spread use of cheap syringes.
But the reality is, no one really knows for sure.