[CobaltBlue]

Which would tend to suggest that present-day Botswanans are descended from people who were never exposed to HIV, or that, for some unknown reason, Africans with resistance to HIV died out for other reasons.

I've seen the data on European genetic resistance to HIV before - as I recall, Africans do not carry the genetic immunity to HIV found in Europeans.

I can't make out why there is speculation that immunity to HIV is somehow related to immunity to smallpox other than coincidence that both exist in the same populations. Given that smallpox has been eradicated, how can we know unless smallpox somehow becomes endemic/pandemic again?

I suppose they could test tissue from people carrying what is believed to be genetic immunity to HIV to see if they are immune to cowpox - if that's been tried I haven't seen it.

[Doctor Stochastic]

One point about smallpox as compared to plague is that the smallpox agent is a virus and plague is a bactium (New Mexico, Land of the Flea, Home of the Plague.) AIDS is virally caused so one would expect that smallpox defence may be of more use than a plague defence. Still, I don't know how close HIV is to smallpox.

[jennyp]

I suppose they could test tissue from people carrying what is believed to be genetic immunity to HIV to see if they are immune to cowpox - if that's been tried I haven't seen it.

Apparently they're going to try something similar...

The next step is to look at disease such as smallpox and perhaps cholera, he says. Researchers plan to see if the mutation protects mice from mousepox, a relative of smallpox in humans.