To summarize some salient facts discussed in Chapter 1, HIV is transmitted in three major ways in Africa: (1) through sexual intercourse, (2) through contaminated blood supplies (very rarely through sharing hypodermic syringes or through any sort of skin-piercing traditional healing practices), and (3) through perinatal mother-to-child transmission (pediatric AIDS). Prevention of HTV infection through contaminated blood supplies is a technical problem of screening. Prevention of "vertical" transmission lies at this stage in preventing the heterosexual infection of the mother in the first place. In any case, the second and third transition modes together account for less than 20 percent of HIV infection cases in Africa.