Proportion of HIV infections attributable to other sexually transmitted diseases in a rural Ugandan population: Simulation model estimates

Abstract

Background. Unprotected heterosexual contact in the presence of other sexually transmitted diseases (STD) enhances the probability of HIV transmission. The objective of this study was to estimate the proportion of HIV infections attributable to STD in rural Uganda. Methods. Simulation modelling scenarios of the transmission dynamics of HIV infection and of ulcerative and non-ulcerative STD were employed to address this objective, drawing on data from a specific rural population cohort of 10,000 in south-west Uganda. Results. in simulations of the initial 10-year period of the HIV epidemic (1980-1990), over 90% of HIV infections were attributed to STD. Even given conservative assumptions about the prevalence of STD and about their enhancing effects on HIV transmission, STD played a critical role in the rapid and extensive spread of HIV infection. The role of STD decreased with progression of the HIV epidemic. Conclusions. In developing countries, control of the spread of HIV infection may benefit substantially from successful STD intervention programmes, and particularly in areas where HIV infection is not already well established.