Although inequality is often measured through three critical indicators-education, income and life expectancy-health-related differences are also essential elements for explaining levels of equality or inequality in modern societies. Investment and investigation in health also involve inequalities at the global level, and this includes insufficient North-South transfer of funds, technology and expertise in the health field, including the specific area of communicable diseases. Globally, epidemics and outbreaks in any geographic region can represent international public health emergencies, and this type of threat requires a global response. Therefore, given the need to strengthen the global capacity for dealing with threats of infectious diseases, a framework is needed for collaboration on alerting the world to epidemics and responding to public health emergencies. This is necessary to guarantee a high level of security against the dissemination of communicable diseases in an ever more globalized world. In response to these needs, international health agencies have put a number of strategies into practice in order to contribute to the control of communicable diseases in poor countries. The principle strategies include: 1) implementation of mechanisms for international epidemiologic surveillance; 2) use of international law to support the control of communicable diseases; 3) international cooperation on health matters; 4) strategies to strengthen primary care services and health systems in general; 5) promotion of the transfer of resources for research and development from the North to the South.