COMPARISON OF TRANSMISSION RATES OF HIV-1 AND HIV-2 IN A COHORT OF PROSTITUTES IN SENEGAL

To explore the biological similarities and differences between the HIV -1 and HIV-2 viruses, we model the probability of male-to-female trans mission of either HIV virus as a function of the number of sexual part ners, the prevalence of the viruses and the infectivity per contact. U sing maximum likelihood estimation theory and data from a prospective study of registered female prostitutes in Dakar, Senegal, we estimate and compare the infectivities of HIV-1 and HIV-2. Graphical goodness-o f-fit methods are used to show that our model fits the data well. We f ind that in male-to-female transmission HIV-1 is significantly more in fectious than HIV-2. This finding is consistent with other data from l aboratory and epidemiologic studies comparing the biology of HIV-1 and HIV-2.