Alive and Well, Aids Alternatives.

Alive and Well is an organization that doubts that a person develops AIDS from an advanced on set of HIV. They say that AIDS comes from stress, malnutrition, RV, and recreational drug use. They all so go onto say that things like there is no AIDS problem in Africa
Here is some more info on them.
en.wikipedia.org...

My question however, is it in any way scientifically feasible that AIDS comes from anywhere other than HIV, and if so what else could cause this syndrome?
I know that it is extremely unlikely that Alive and Well's hypothesis of stress and malnutrition is correct, but what about a reaction between HIV and Retro Virus?