This paper considers the implications that distinct organizing principles for health systems have for the control of infectious diseases. The paper takes the health systems in Mexico and Cuba as examples of neighboring but widely divergent systems, producing different pubic health outcomes. The paper will look at the dissimilar organizing principles of these two systems, along with their programs and outcomes in relation to five of the most important and dangerous infectious diseases. The paper will then consider what broader lessons might be drawn from the experiences in Cuba and Mexico. Mexico has pursued a federal and neoliberal system, based on tripartite social insurance (State, employer, and employee contributions), private "partnerships" (private-for-profit investment in public services), and competitive service provision (competitive rather than coordinated services). On the other hand, Cuba has maintained a public system, with guaranteed free and universal access, universal patient registration, assignment of all persons to a family doctor, and centralized public coordination of services. How have these two health systems approached tuberculosis, HIV/AIDS, diarrhea, measles, and malaria? In recent decades both countries have made substantial progress in dealing with these five diseases, but Cuba has maintained a superior performance, despite having a lower income per capita and less total Government funding available. This at first seems to contradict the broad international correlation between income levels and health outcomes. It also poses questions for the "pro-poor" policies that the Organization for Economic Cooperation and Development (OECD) (the wealthy countries' club) suggests for developing countries. Those policies emphasize "scaling up resources and private investment," including with competitive service provision and expanded "choice" in health services (1, 2). Important research (3) has demonstrated that general income growth has less correlation with reductions in major categories of mortality and with other major advances in public health than do the education of women and the implementation of appropriate technology. The question of the contribution of other social and organizational factors in reducing mortality and morbidity levels is left open. However, it is well established, for example, that major reductions in maternal mortality are much more strongly linked to the presence of a skilled birth assistant than to expensive facilities or high technology (4). What then of infectious disease? In most poor and developing countries, epidemics of tuberculosis, HIV/AIDS, diarrhea, measles, and malaria are major killers. While highly controlled in most wealthy or "low-mortality" countries, these five diseases each kill many hundreds of thousands of people worldwide every year, as do poor maternal-infant health conditions and nutritional disorders. In 2002, for example, HIV/AIDS killed 2.8 million persons worldwide, tuberculosis 1.6 million, diarrheal diseases 1.8 million, malaria 1.2 million, and measles 760 000 (5). Beyond the bland demands for "broad-based economic growth" (6), how might the organization of health policy be linked to substantial advances in combating these diseases? Most of the serious infectious diseases that affect developing countries are no longer the primary health problems of the more wealthy countries. Nor are infectious diseases the main problems of Mexico and Cuba. In recent years, these two countries have been wrestling with these "preventable" diseases and, to varying degrees, have overcome them. Because of their divergent systems and their differing outcomes with infectious diseases, it seems that a comparative study of Mexico and Cuba might be enlightening. [ABSTRACT FROM AUTHOR]