From the above link
Besides lifestyle factors, there might be genetic factors in those numbers.
People of European decent (though the numbers are low) who have the ccr5 gene mutation show to have limited resistance to HIV. This might explain why HIV is not as wide spread in the US and Europe as it is in Africa.
Besides a lifestyle disease, I am starting to wonder if HIV is also a genetic disease. People without certain genetic traits are being killed off.
What we have been seeing since the 1980s is a slower replay of what happened in the middle ages. Historians noted that the plague would kill one family, skip a family, and then kill the next family. The people back then did not understand why certain families were not killed by the plague.
Today, and with the help of genetics, we understand that certain races are resistant (not immune) to certain diseases.
Not as evidence, but as a comparison.
What the black death did in a couple of years, HIV is taking decades to do.