Transfusion-transmitted diseases: risks, prevention and perspectives

During the past decades major improvements in blood safety have been achiev ed, both in developed and developing countries. The introduction of donor c ounseling and screening for different pathogens has made blood a very safe product, especially in developed countries. However, even in these countrie s, there is still a residual risk for the transmission of several pathogens . For viruses such as the human immunodeficiency virus (HIV), and the hepat itis viruses B and C, this is due mainly to window-period donations. Furthe rmore, the threat of newly emerging pathogens which can affect blood safety is always present. For example, the implications of the agent causing new Variant Creutzfeld-Jakob disease for transfusion practice are not yet clear . Finally, there are several pathogens, e.g. CMV and parvo B19, which are c ommon in the general donor population, and might pose a serious threat in s elected groups of immunosuppressed patients. In the future, further improve ments in blood safety are expected from the introduction of polymerase chai n reaction for testing and from the implementation of photochemical deconta mination for cellular blood products. The situation in transfusion medicine in the developing world is much less favorable, due mainly to a higher inc idence and prevalence of infectious diseases.