HIV may have been present in remote regions of Central Africa for a long time, just infecting small numbers of people. The social customs of traditional village life limited the spread of HIV and other sexually transmitted diseases, since extramarital and premarital trysts were condemned and virtually impossible in the claustrophobic cultures of tiny communities scattered throughout equatorial Africa. The paving of the highway from Kinshasa in Zaire to Mombasa on the Indian Ocean may have helped to open the way for the HIV virus to spread. Along it are full service establishments with food, beer, bed, and a woman. For years they have been continually exposed to HIV, yet they remain free of any trace of the virus.
Tests reveal no antibodies or the viral organism.
They appear to have specialized cells that can kill off the virus before it can inflict any damage. Urbanization and its resulting erosion of traditional sex taboos and lifestyles may be the key to the emergence of HIV in Africa. Urban centers are an ecosystem than can amplify infectious contagious diseases. AIDS in Africa did not spread simply because the virus was present. The change in the interaction between the agent, the host and the environment is usually required for the epidemic.