Forty years ago, the age-old battle against infectious diseases as a major threat to human health was believed close to being won. However, by the late twentieth century, the increase of emerging and reemerging infectious diseases was evident in both low and high income countries. About 30 new infectious diseases have been identified in the last 20 years. Among the new diseases, and most importantly, the Human Immunodeficiency Virus (HIV) epidemic, with 40 million persons infected and 25 million deaths since its first description, presents one of the most significant health, societal and...