[A comparative study of the emergence of the AIDS and syphilis pandemics].

A historical and comparative study of the origins and emergence of syphilis and AIDS show that both result from human intrusions. Treponema probably existed in primates before human infection, and nonvenereal treponemal infection existed in prehistoric tropical Africa. When humans began wearing clothes, the disappearance of endemic infection ended immunity and led to receptivity to venereal infection. It was long thought that syphilis was first introduced in Europe by the conquistadors, but lesions typical of treponematosis dating from before the Common Era have been found in Europe. It is possible that the first navigators transferred treponemal infections to Latin America. AIDS seems to have appeared throughout the Congo River basin around 1950, and genetic studies attest to its long history in primates. It may have resulted from the Bantu migration and its strong human intrusion into the forest. After the initial human infection, new epidemiological factors in a transformed environment and behavioral changes led at 500-year intervals (1480-1490 for syphilis and 1940-1950 for AIDS) to the widespread emergence and subsequent pandemic of each disease.