[Health alert management and emerging risk].

Following health crisis that have occurred in the nineties (contaminated blood, mad cow, asbestos, etc.) and more recently those generated by the heat wave in 2003 or by emerging infectious pathogens (SARS, West Nile, Chikungunya, H5N1, H1N1…), a real health vigilance system has been progressively developed in France. After a brief historical overview of the health alert system, this article will give the guiding principles of its current organization in France and will present two examples of recent health alerts (Chikungunya in the Reunion Island in 2005-2006 and hepatitis A outbreak in the Côtes-d'Armor in August 2007), that have needed the implementation of preventive measures regarding the blood donor selection. These two examples have shown that the position of the alert in the French health vigilance system needs to be very close to the event. In that case, health alert is a very useful tool for decision making especially when measures have to be taken to prevent transfusion-transmitted pathogens.