The geographical analysis of the main data on the HIV1 epidemic in Central Africa shows a frontline which has not moved significantly since 1985. The absence of a progressive increase between the countries, demonstrating a discontinuity in space, combined with the observed human and physical continuity within the areas, raises several questions. Are the low-rate areas facing only a simple delay in the diffusion, or is there a real difference between the epidemiological patterns of HIV1 in the two areas? The last hypothesis would impose a revision of the concept of an homogeneous pattern in the epidemiology of HIV1 in Africa. The need for further research is emphasized with the aim of precisely targeting preventive intervention.
PIP: Interventions against HIV and AIDS are typically designed and implemented to target 1 or more of 3 epidemiological patterns found in countries worldwide. Given the heterogeneity of infection and prevalence observed within certain regions and communities, the available knowledge of HIV epidemic patterns needs to be broadened through a multidisciplinary approach which includes an analysis of geographical concepts and boundaries. Geographical analysis of main data on the HIV-1 epidemic in central Africa reveals a frontline which has not moved significantly since 1985. This phenomenon leads one to question reasons for the absence of a progressive increase between countries in the context of human and physical continuity across areas Speculation exists over whether diffusion to low-rate areas is simply delayed or whether a real difference exists between epidemiological patterns. Evidence indicates that the HIV epidemic is heterogeneous throughout Africa and follows different diffusion patterns from 1 ecosystem to another. While HIV is spread regionally primarily through heterosexual networks, it is also feasible that other unexplored routes of transmission may play a role at least during the early phases of the epidemic and may be associated with other causative cofactors. A threshold phenomenon could also be at work in which epidemic waves are set forth after building to critical values of seroprevalence among fringe groups. These phenomenon most likely combine to explaining the observed differing patterns of diffusion in central Africa. Research is needed to better understand prevailing patterns of infection and develop appropriate preventive interventions.