[Emergent viral threats in blood transfusion]

During the last 20 years, the safety of blood products increased dramatically with regard to the infectious risk and notably to that represented by retroviruses (HIV and HTLV) and hepatitis B and C viruses. The aim of this review is to identify the residual and emergent viral threats that could be responsible for the occurring of new contaminations in the receivers of blood products. Beside many other viruses (HHV-8, erythrovirus B19, hepatitis A and E viruses...), a special attention has been paid to emerging arbovirus diseases (West Nile virus infection, dengue, chikungunya) that threaten to occur in the French metropolitan area following the implantation in Europe of the mosquito Aedes albopictus, the main vector of dengue and chikungunya in temperate regions. Another blood-linked risk, notably in United Kingdom and France, is the prion agent responsible for the variant form of the Creutzfeldt-Jakob disease. The review is concluded by a brief overview of the measures aimed to control these emergences, including the exclusion of at-risk donors, the diagnostic tests able to detect a specific agent, the leukocyte reduction of labile blood products, and the physical or chemical treatments aiming the nonspecific inactivation of infectious agents potentially present in blood without impairing significantly the physiological properties of blood compounds. The ability to control prospectively the new viral risks linked to blood products is a challenge for the preservation of the confidence of both clinicians and receivers in the safety of blood transfusion.