It has been 26 years since the acquired immune deficiency syndrome (AIDS) was first recognized (see review ). In the ensuing time, AIDS has become an unprecedented global pandemic. Today, approximately 33 million people worldwide are infected with HIV, the virus that causes AIDS. In 2007, 2.5 million people became newly infected; and around 2.1 million died of AIDS in 2006. Each day, ~10,000 new individuals become HIV seropositive with 95% residing in resource-poor developing nations. A cumulative global count shows that more than 25 million people have already died from AIDS, a number exceeding 60 times the total American casualties in World War II. Regrettably, half of all people are infected with HIV before age 25, and are killed by AIDS before they turn 35.