Sexual transmission of HIV in Africa

Walker PR, Worobey M, Rambaut A, Holmes EC & Pybus OG

(2003) Nature 422, 679.

The HIV epidemic in sub-Saharan Africa continues to grow at an alarming rate with 3.5 million people infected last year alone. It has recently been proposed that heterosexual transmission cannot account for more than 35% of HIV incidence in sub-Saharan Africa, and that parenteral transmission, most likely through unsterile medical practices, is the main route of infection. A key prediction of this hypothesis is that the epidemic history of HIV in sub-Saharan Africa would be similar to that of blood-borne pathogens. To test this we compared prevalence estimates of HIV with hepatitis C virus (HCV), which has a far greater rate of parenteral than sexual transmission. We show that HIV and HCV have such different epidemic histories in sub-Saharan Africa that parenteral transmission is unlikely to be the main source of HIV infection.

Andrew Rambaut, 2007