 The United States began testing AZT treatments in Africa in 1994, through projects funded by the Centers for Disease Control (CDC), the World Health Organization (WHO), and the National Institutes of Health (NIH).It included testing of over 17,000 women for a medication that prevents mother-to-child transmission of HIV/AIDS.The subjects did not fully understand the testing methods, the effectiveness, the possible dangers, or the nature of a placebo in testing situations.