Non conventional transmissible agents and emerging viruses

Most infections occurring after blood transfusion or tissue engraftment come from a contamination of bacterial origin. Apart from these cases, most contaminating infectious pathogens are of known origin and detected for the blood donation qualification. In certain cases, there is the possibility of blood transmission of unknown infectious pathogens; sometimes, such pathogen is not unknown but very uncommon or unlikely. Consequences of blood transmission of such pathogens are different according to the pathogen itself and to the immune status of the recipient. This leads to the principle of precaution. The present manuscript aims at discussing these aspects. (C) 2003 Editions scientifiques et medicales Elsevier SAS. Tous droits reserves.