Preface Guillermo Soberón Acevedo* * Mexican Health Foundation Ever since its emergence, the Acquired Immune Deficiency Syndrome (AIDS) epidemic has constituted a challenge for the scientific community and for civil society. The challenge involves, on the one hand, the need to keep abreast of the rapid advance of the accumulated knowledge on AIDS and, on the other, the need to apply such knowledge swiftly. That is why several updating mechanisms on the subject have been devised, such as the publication of specialized scientific journals (for example, JAIDS, AIDS, Human Retrovirology, AIDS Education and Prevention, among others). Nevertheless, given the time which elapses between the completion of research projects and their eventual publication in scientific journals, alternatives have been sought to allow one to acquire such knowledge as soon as possible. To this end, national and international conferences, seminars, workshops and symposia have been organized on the general subject of AIDS or on specific AIDS-related aspects; for instance, the X International Conference on AIDS adopted the slogan “The Global Challenge of AIDS: Together for the Future”, and the XI International Conference the slogan “One World, One Hope.” The AIDS regional initiative for Latin America and the Caribbean (SIDALAC) was promoted by the World Bank in a similar fashion as previous experiences in Africa and in Asia. This initiative is now part of the United Nations Programme on AIDS (UNAIDS), co-sponsored by six of the system’s agencies: the United Nations Children’s Fund (UNICEF); the United Nations Development Program (UNDP); the United Nations Fund for Population Activities (UNFPA); the United Nations Educational, Scientific and Cultural Organization (UNESCO); the World Health Organization (WHO); and the World Bank. This initiative’s implementing agency is the Mexican Health Foundation ÄFundación Mexicana para la Salud (FUNSALUD). Starting from the conviction that, to successfully modify the course of the AIDS’s epidemic and to provide adequate medical care to those affected, it is of paramount importance to involve the participation of high-ranking government officials within and outside the health system, as well as that of different social groups. SIDALAC is a regional program whose main purpose is: to develop research projects directed at providing useful information for the strategic planning in the prevention of HIV/AIDS and in health-care services for the affected, and to widely disseminate the results of such research projects as well as those arising from the exchange of experiences and lessons learned in other parts of the world. International conferences on AIDS are now held every two years (from 1994 onward), and their high cost for Latin American and Caribbean countries implies that most experts on the subject and the majority of decision makers in related areas shall not be able to attend them, so that often they will learn about the contents of such conferences through the media, for example, newspapers. This work was planned with the objective of widely disseminating the results of research studies providing useful information for the strategic planning in the prevention of HIV/AIDS and in health-care services for the affected as well as the results arising from the exchange of experiences and lessons learned in other parts of the world that may be applied in Latin American and Caribbean countries. To that end, a group of nine experts was gathered, in order that each one of them should write a manuscript summarizing the current state of knowledge, the most relevant questions to be answered in each area covered, and to note which ones were answered at the XI International Conference on AIDS, held in Vancouver, Canada, in July 1996. Several of the participants had financial support from the United States Agency for International Development to attend the Vancouver conference; other participants attended the conference thanks to the support of their own institutions. This document reviews the main advances that have emerged in the basic and clinical sciences with respect to the disease; moreover, it states the epidemiological patterns of HIV/AIDS, putting special emphasis on the indicators of impact. In addition, it presents certain aspects of importance for the prevention of the HIV infection and a case study of the expenses produced by this epidemic in one country of the region. It should be mentioned that to consider such important topics from a community standpoint two experts were invited: Dr. Susan Vandale, who serves as technical secretary of the Latin American Working Group on Women and AIDS; and Javier Hourcade, representative of the Global Network of People Living With HIV/AIDS in Latin America. Furthermore, the first chapter of this work presents an overall review of what the different authors examine in the subsequent chapters, adding the view of the editor, who also serves as executive coordinator of SIDALAC.